diff --git a/BUILD b/BUILD
index 761200716e3..b934a5f337c 100644
--- a/BUILD
+++ b/BUILD
@@ -52,6 +52,7 @@ cc_library(
     "src/core/lib/support/block_annotate.h",
     "src/core/lib/support/env.h",
     "src/core/lib/support/murmur_hash.h",
+    "src/core/lib/support/percent_encoding.h",
     "src/core/lib/support/stack_lockfree.h",
     "src/core/lib/support/string.h",
     "src/core/lib/support/string_windows.h",
@@ -79,6 +80,7 @@ cc_library(
     "src/core/lib/support/log_posix.c",
     "src/core/lib/support/log_windows.c",
     "src/core/lib/support/murmur_hash.c",
+    "src/core/lib/support/percent_encoding.c",
     "src/core/lib/support/slice.c",
     "src/core/lib/support/slice_buffer.c",
     "src/core/lib/support/stack_lockfree.c",
@@ -2067,6 +2069,7 @@ objc_library(
     "src/core/lib/support/log_posix.c",
     "src/core/lib/support/log_windows.c",
     "src/core/lib/support/murmur_hash.c",
+    "src/core/lib/support/percent_encoding.c",
     "src/core/lib/support/slice.c",
     "src/core/lib/support/slice_buffer.c",
     "src/core/lib/support/stack_lockfree.c",
@@ -2140,6 +2143,7 @@ objc_library(
     "src/core/lib/support/block_annotate.h",
     "src/core/lib/support/env.h",
     "src/core/lib/support/murmur_hash.h",
+    "src/core/lib/support/percent_encoding.h",
     "src/core/lib/support/stack_lockfree.h",
     "src/core/lib/support/string.h",
     "src/core/lib/support/string_windows.h",
diff --git a/CMakeLists.txt b/CMakeLists.txt
index b339aaaefd5..7c6ae34e8d5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -192,6 +192,7 @@ add_library(gpr
   src/core/lib/support/log_posix.c
   src/core/lib/support/log_windows.c
   src/core/lib/support/murmur_hash.c
+  src/core/lib/support/percent_encoding.c
   src/core/lib/support/slice.c
   src/core/lib/support/slice_buffer.c
   src/core/lib/support/stack_lockfree.c
@@ -1750,6 +1751,28 @@ if (gRPC_INSTALL)
 endif()
 
 
+add_executable(gen_percent_encoding_tables
+  tools/codegen/core/gen_percent_encoding_tables.c
+)
+
+target_include_directories(gen_percent_encoding_tables
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include
+  PRIVATE ${BORINGSSL_ROOT_DIR}/include
+  PRIVATE ${PROTOBUF_ROOT_DIR}/src
+  PRIVATE ${ZLIB_ROOT_DIR}
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/zlib
+)
+
+
+
+install(TARGETS gen_percent_encoding_tables EXPORT gRPCTargets
+  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+)
+
+
 add_executable(grpc_create_jwt
   test/core/security/create_jwt.c
 )
diff --git a/Makefile b/Makefile
index 662101f2760..bb0c5bde8e8 100644
--- a/Makefile
+++ b/Makefile
@@ -930,6 +930,7 @@ fling_stream_test: $(BINDIR)/$(CONFIG)/fling_stream_test
 fling_test: $(BINDIR)/$(CONFIG)/fling_test
 gen_hpack_tables: $(BINDIR)/$(CONFIG)/gen_hpack_tables
 gen_legal_metadata_characters: $(BINDIR)/$(CONFIG)/gen_legal_metadata_characters
+gen_percent_encoding_tables: $(BINDIR)/$(CONFIG)/gen_percent_encoding_tables
 goaway_server_test: $(BINDIR)/$(CONFIG)/goaway_server_test
 gpr_avl_test: $(BINDIR)/$(CONFIG)/gpr_avl_test
 gpr_backoff_test: $(BINDIR)/$(CONFIG)/gpr_backoff_test
@@ -939,6 +940,7 @@ gpr_env_test: $(BINDIR)/$(CONFIG)/gpr_env_test
 gpr_histogram_test: $(BINDIR)/$(CONFIG)/gpr_histogram_test
 gpr_host_port_test: $(BINDIR)/$(CONFIG)/gpr_host_port_test
 gpr_log_test: $(BINDIR)/$(CONFIG)/gpr_log_test
+gpr_percent_encoding_test: $(BINDIR)/$(CONFIG)/gpr_percent_encoding_test
 gpr_slice_buffer_test: $(BINDIR)/$(CONFIG)/gpr_slice_buffer_test
 gpr_slice_test: $(BINDIR)/$(CONFIG)/gpr_slice_test
 gpr_stack_lockfree_test: $(BINDIR)/$(CONFIG)/gpr_stack_lockfree_test
@@ -993,6 +995,8 @@ murmur_hash_test: $(BINDIR)/$(CONFIG)/murmur_hash_test
 nanopb_fuzzer_response_test: $(BINDIR)/$(CONFIG)/nanopb_fuzzer_response_test
 nanopb_fuzzer_serverlist_test: $(BINDIR)/$(CONFIG)/nanopb_fuzzer_serverlist_test
 no_server_test: $(BINDIR)/$(CONFIG)/no_server_test
+percent_decode_fuzzer: $(BINDIR)/$(CONFIG)/percent_decode_fuzzer
+percent_encode_fuzzer: $(BINDIR)/$(CONFIG)/percent_encode_fuzzer
 resolve_address_test: $(BINDIR)/$(CONFIG)/resolve_address_test
 secure_channel_create_test: $(BINDIR)/$(CONFIG)/secure_channel_create_test
 secure_endpoint_test: $(BINDIR)/$(CONFIG)/secure_endpoint_test
@@ -1159,6 +1163,8 @@ http_response_fuzzer_test_one_entry: $(BINDIR)/$(CONFIG)/http_response_fuzzer_te
 json_fuzzer_test_one_entry: $(BINDIR)/$(CONFIG)/json_fuzzer_test_one_entry
 nanopb_fuzzer_response_test_one_entry: $(BINDIR)/$(CONFIG)/nanopb_fuzzer_response_test_one_entry
 nanopb_fuzzer_serverlist_test_one_entry: $(BINDIR)/$(CONFIG)/nanopb_fuzzer_serverlist_test_one_entry
+percent_decode_fuzzer_one_entry: $(BINDIR)/$(CONFIG)/percent_decode_fuzzer_one_entry
+percent_encode_fuzzer_one_entry: $(BINDIR)/$(CONFIG)/percent_encode_fuzzer_one_entry
 server_fuzzer_one_entry: $(BINDIR)/$(CONFIG)/server_fuzzer_one_entry
 uri_fuzzer_test_one_entry: $(BINDIR)/$(CONFIG)/uri_fuzzer_test_one_entry
 
@@ -1258,6 +1264,7 @@ buildtests_c: privatelibs_c \
   $(BINDIR)/$(CONFIG)/gpr_histogram_test \
   $(BINDIR)/$(CONFIG)/gpr_host_port_test \
   $(BINDIR)/$(CONFIG)/gpr_log_test \
+  $(BINDIR)/$(CONFIG)/gpr_percent_encoding_test \
   $(BINDIR)/$(CONFIG)/gpr_slice_buffer_test \
   $(BINDIR)/$(CONFIG)/gpr_slice_test \
   $(BINDIR)/$(CONFIG)/gpr_stack_lockfree_test \
@@ -1376,6 +1383,8 @@ buildtests_c: privatelibs_c \
   $(BINDIR)/$(CONFIG)/json_fuzzer_test_one_entry \
   $(BINDIR)/$(CONFIG)/nanopb_fuzzer_response_test_one_entry \
   $(BINDIR)/$(CONFIG)/nanopb_fuzzer_serverlist_test_one_entry \
+  $(BINDIR)/$(CONFIG)/percent_decode_fuzzer_one_entry \
+  $(BINDIR)/$(CONFIG)/percent_encode_fuzzer_one_entry \
   $(BINDIR)/$(CONFIG)/server_fuzzer_one_entry \
   $(BINDIR)/$(CONFIG)/uri_fuzzer_test_one_entry \
 
@@ -1592,6 +1601,8 @@ test_c: buildtests_c
 	$(Q) $(BINDIR)/$(CONFIG)/gpr_host_port_test || ( echo test gpr_host_port_test failed ; exit 1 )
 	$(E) "[RUN]     Testing gpr_log_test"
 	$(Q) $(BINDIR)/$(CONFIG)/gpr_log_test || ( echo test gpr_log_test failed ; exit 1 )
+	$(E) "[RUN]     Testing gpr_percent_encoding_test"
+	$(Q) $(BINDIR)/$(CONFIG)/gpr_percent_encoding_test || ( echo test gpr_percent_encoding_test failed ; exit 1 )
 	$(E) "[RUN]     Testing gpr_slice_buffer_test"
 	$(Q) $(BINDIR)/$(CONFIG)/gpr_slice_buffer_test || ( echo test gpr_slice_buffer_test failed ; exit 1 )
 	$(E) "[RUN]     Testing gpr_slice_test"
@@ -1825,7 +1836,7 @@ test_python: static_c
 tools: tools_c tools_cxx
 
 
-tools_c: privatelibs_c $(BINDIR)/$(CONFIG)/gen_hpack_tables $(BINDIR)/$(CONFIG)/gen_legal_metadata_characters $(BINDIR)/$(CONFIG)/grpc_create_jwt $(BINDIR)/$(CONFIG)/grpc_print_google_default_creds_token $(BINDIR)/$(CONFIG)/grpc_verify_jwt
+tools_c: privatelibs_c $(BINDIR)/$(CONFIG)/gen_hpack_tables $(BINDIR)/$(CONFIG)/gen_legal_metadata_characters $(BINDIR)/$(CONFIG)/gen_percent_encoding_tables $(BINDIR)/$(CONFIG)/grpc_create_jwt $(BINDIR)/$(CONFIG)/grpc_print_google_default_creds_token $(BINDIR)/$(CONFIG)/grpc_verify_jwt
 
 tools_cxx: privatelibs_cxx
 
@@ -2374,6 +2385,7 @@ LIBGPR_SRC = \
     src/core/lib/support/log_posix.c \
     src/core/lib/support/log_windows.c \
     src/core/lib/support/murmur_hash.c \
+    src/core/lib/support/percent_encoding.c \
     src/core/lib/support/slice.c \
     src/core/lib/support/slice_buffer.c \
     src/core/lib/support/stack_lockfree.c \
@@ -7887,6 +7899,38 @@ endif
 endif
 
 
+GEN_PERCENT_ENCODING_TABLES_SRC = \
+    tools/codegen/core/gen_percent_encoding_tables.c \
+
+GEN_PERCENT_ENCODING_TABLES_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GEN_PERCENT_ENCODING_TABLES_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/gen_percent_encoding_tables: openssl_dep_error
+
+else
+
+
+
+$(BINDIR)/$(CONFIG)/gen_percent_encoding_tables: $(GEN_PERCENT_ENCODING_TABLES_OBJS)
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LD) $(LDFLAGS) $(GEN_PERCENT_ENCODING_TABLES_OBJS) $(LDLIBS) $(LDLIBS_SECURE) -o $(BINDIR)/$(CONFIG)/gen_percent_encoding_tables
+
+endif
+
+$(OBJDIR)/$(CONFIG)/tools/codegen/core/gen_percent_encoding_tables.o: 
+
+deps_gen_percent_encoding_tables: $(GEN_PERCENT_ENCODING_TABLES_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(GEN_PERCENT_ENCODING_TABLES_OBJS:.o=.dep)
+endif
+endif
+
+
 GOAWAY_SERVER_TEST_SRC = \
     test/core/end2end/goaway_server_test.c \
 
@@ -8175,6 +8219,38 @@ endif
 endif
 
 
+GPR_PERCENT_ENCODING_TEST_SRC = \
+    test/core/support/percent_encoding_test.c \
+
+GPR_PERCENT_ENCODING_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GPR_PERCENT_ENCODING_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/gpr_percent_encoding_test: openssl_dep_error
+
+else
+
+
+
+$(BINDIR)/$(CONFIG)/gpr_percent_encoding_test: $(GPR_PERCENT_ENCODING_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LD) $(LDFLAGS) $(GPR_PERCENT_ENCODING_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -o $(BINDIR)/$(CONFIG)/gpr_percent_encoding_test
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/support/percent_encoding_test.o:  $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_gpr_percent_encoding_test: $(GPR_PERCENT_ENCODING_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(GPR_PERCENT_ENCODING_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 GPR_SLICE_BUFFER_TEST_SRC = \
     test/core/support/slice_buffer_test.c \
 
@@ -9903,6 +9979,70 @@ endif
 endif
 
 
+PERCENT_DECODE_FUZZER_SRC = \
+    test/core/support/percent_decode_fuzzer.c \
+
+PERCENT_DECODE_FUZZER_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(PERCENT_DECODE_FUZZER_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/percent_decode_fuzzer: openssl_dep_error
+
+else
+
+
+
+$(BINDIR)/$(CONFIG)/percent_decode_fuzzer: $(PERCENT_DECODE_FUZZER_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) $(PERCENT_DECODE_FUZZER_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -lFuzzer -o $(BINDIR)/$(CONFIG)/percent_decode_fuzzer
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/support/percent_decode_fuzzer.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_percent_decode_fuzzer: $(PERCENT_DECODE_FUZZER_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(PERCENT_DECODE_FUZZER_OBJS:.o=.dep)
+endif
+endif
+
+
+PERCENT_ENCODE_FUZZER_SRC = \
+    test/core/support/percent_encode_fuzzer.c \
+
+PERCENT_ENCODE_FUZZER_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(PERCENT_ENCODE_FUZZER_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/percent_encode_fuzzer: openssl_dep_error
+
+else
+
+
+
+$(BINDIR)/$(CONFIG)/percent_encode_fuzzer: $(PERCENT_ENCODE_FUZZER_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) $(PERCENT_ENCODE_FUZZER_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -lFuzzer -o $(BINDIR)/$(CONFIG)/percent_encode_fuzzer
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/support/percent_encode_fuzzer.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_percent_encode_fuzzer: $(PERCENT_ENCODE_FUZZER_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(PERCENT_ENCODE_FUZZER_OBJS:.o=.dep)
+endif
+endif
+
+
 RESOLVE_ADDRESS_TEST_SRC = \
     test/core/iomgr/resolve_address_test.c \
 
@@ -15376,6 +15516,76 @@ endif
 endif
 
 
+PERCENT_DECODE_FUZZER_ONE_ENTRY_SRC = \
+    test/core/support/percent_decode_fuzzer.c \
+    test/core/util/one_corpus_entry_fuzzer.c \
+
+PERCENT_DECODE_FUZZER_ONE_ENTRY_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(PERCENT_DECODE_FUZZER_ONE_ENTRY_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/percent_decode_fuzzer_one_entry: openssl_dep_error
+
+else
+
+
+
+$(BINDIR)/$(CONFIG)/percent_decode_fuzzer_one_entry: $(PERCENT_DECODE_FUZZER_ONE_ENTRY_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LD) $(LDFLAGS) $(PERCENT_DECODE_FUZZER_ONE_ENTRY_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -o $(BINDIR)/$(CONFIG)/percent_decode_fuzzer_one_entry
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/support/percent_decode_fuzzer.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+$(OBJDIR)/$(CONFIG)/test/core/util/one_corpus_entry_fuzzer.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_percent_decode_fuzzer_one_entry: $(PERCENT_DECODE_FUZZER_ONE_ENTRY_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(PERCENT_DECODE_FUZZER_ONE_ENTRY_OBJS:.o=.dep)
+endif
+endif
+
+
+PERCENT_ENCODE_FUZZER_ONE_ENTRY_SRC = \
+    test/core/support/percent_encode_fuzzer.c \
+    test/core/util/one_corpus_entry_fuzzer.c \
+
+PERCENT_ENCODE_FUZZER_ONE_ENTRY_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(PERCENT_ENCODE_FUZZER_ONE_ENTRY_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/percent_encode_fuzzer_one_entry: openssl_dep_error
+
+else
+
+
+
+$(BINDIR)/$(CONFIG)/percent_encode_fuzzer_one_entry: $(PERCENT_ENCODE_FUZZER_ONE_ENTRY_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LD) $(LDFLAGS) $(PERCENT_ENCODE_FUZZER_ONE_ENTRY_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -o $(BINDIR)/$(CONFIG)/percent_encode_fuzzer_one_entry
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/support/percent_encode_fuzzer.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+$(OBJDIR)/$(CONFIG)/test/core/util/one_corpus_entry_fuzzer.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_percent_encode_fuzzer_one_entry: $(PERCENT_ENCODE_FUZZER_ONE_ENTRY_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(PERCENT_ENCODE_FUZZER_ONE_ENTRY_OBJS:.o=.dep)
+endif
+endif
+
+
 SERVER_FUZZER_ONE_ENTRY_SRC = \
     test/core/end2end/fuzzers/server_fuzzer.c \
     test/core/util/one_corpus_entry_fuzzer.c \
diff --git a/binding.gyp b/binding.gyp
index c2c8bcf322c..7cc8a58c01c 100644
--- a/binding.gyp
+++ b/binding.gyp
@@ -516,6 +516,7 @@
         'src/core/lib/support/log_posix.c',
         'src/core/lib/support/log_windows.c',
         'src/core/lib/support/murmur_hash.c',
+        'src/core/lib/support/percent_encoding.c',
         'src/core/lib/support/slice.c',
         'src/core/lib/support/slice_buffer.c',
         'src/core/lib/support/stack_lockfree.c',
diff --git a/build.yaml b/build.yaml
index d7578469bed..1f44e794d5e 100644
--- a/build.yaml
+++ b/build.yaml
@@ -83,6 +83,7 @@ filegroups:
   - src/core/lib/support/block_annotate.h
   - src/core/lib/support/env.h
   - src/core/lib/support/murmur_hash.h
+  - src/core/lib/support/percent_encoding.h
   - src/core/lib/support/stack_lockfree.h
   - src/core/lib/support/string.h
   - src/core/lib/support/string_windows.h
@@ -111,6 +112,7 @@ filegroups:
   - src/core/lib/support/log_posix.c
   - src/core/lib/support/log_windows.c
   - src/core/lib/support/murmur_hash.c
+  - src/core/lib/support/percent_encoding.c
   - src/core/lib/support/slice.c
   - src/core/lib/support/slice_buffer.c
   - src/core/lib/support/stack_lockfree.c
@@ -1576,6 +1578,12 @@ targets:
   src:
   - tools/codegen/core/gen_legal_metadata_characters.c
   deps: []
+- name: gen_percent_encoding_tables
+  build: tool
+  language: c
+  src:
+  - tools/codegen/core/gen_percent_encoding_tables.c
+  deps: []
 - name: goaway_server_test
   cpu_cost: 0.1
   build: test
@@ -1655,6 +1663,14 @@ targets:
   deps:
   - gpr_test_util
   - gpr
+- name: gpr_percent_encoding_test
+  build: test
+  language: c
+  src:
+  - test/core/support/percent_encoding_test.c
+  deps:
+  - gpr_test_util
+  - gpr
 - name: gpr_slice_buffer_test
   build: test
   language: c
@@ -2216,6 +2232,32 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: percent_decode_fuzzer
+  build: fuzzer
+  language: c
+  src:
+  - test/core/support/percent_decode_fuzzer.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
+  corpus_dirs:
+  - test/core/support/percent_decode_corpus
+  maxlen: 32
+- name: percent_encode_fuzzer
+  build: fuzzer
+  language: c
+  src:
+  - test/core/support/percent_encode_fuzzer.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
+  corpus_dirs:
+  - test/core/support/percent_encode_corpus
+  maxlen: 32
 - name: resolve_address_test
   build: test
   language: c
diff --git a/config.m4 b/config.m4
index fe22620fa8b..5384585dd6c 100644
--- a/config.m4
+++ b/config.m4
@@ -57,6 +57,7 @@ if test "$PHP_GRPC" != "no"; then
     src/core/lib/support/log_posix.c \
     src/core/lib/support/log_windows.c \
     src/core/lib/support/murmur_hash.c \
+    src/core/lib/support/percent_encoding.c \
     src/core/lib/support/slice.c \
     src/core/lib/support/slice_buffer.c \
     src/core/lib/support/stack_lockfree.c \
diff --git a/gRPC-Core.podspec b/gRPC-Core.podspec
index fe583031bb8..deffa1653ea 100644
--- a/gRPC-Core.podspec
+++ b/gRPC-Core.podspec
@@ -201,6 +201,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/support/block_annotate.h',
                       'src/core/lib/support/env.h',
                       'src/core/lib/support/murmur_hash.h',
+                      'src/core/lib/support/percent_encoding.h',
                       'src/core/lib/support/stack_lockfree.h',
                       'src/core/lib/support/string.h',
                       'src/core/lib/support/string_windows.h',
@@ -228,6 +229,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/support/log_posix.c',
                       'src/core/lib/support/log_windows.c',
                       'src/core/lib/support/murmur_hash.c',
+                      'src/core/lib/support/percent_encoding.c',
                       'src/core/lib/support/slice.c',
                       'src/core/lib/support/slice_buffer.c',
                       'src/core/lib/support/stack_lockfree.c',
@@ -607,6 +609,7 @@ Pod::Spec.new do |s|
                               'src/core/lib/support/block_annotate.h',
                               'src/core/lib/support/env.h',
                               'src/core/lib/support/murmur_hash.h',
+                              'src/core/lib/support/percent_encoding.h',
                               'src/core/lib/support/stack_lockfree.h',
                               'src/core/lib/support/string.h',
                               'src/core/lib/support/string_windows.h',
diff --git a/grpc.gemspec b/grpc.gemspec
index f87f40afe77..f2490060656 100755
--- a/grpc.gemspec
+++ b/grpc.gemspec
@@ -91,6 +91,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/support/block_annotate.h )
   s.files += %w( src/core/lib/support/env.h )
   s.files += %w( src/core/lib/support/murmur_hash.h )
+  s.files += %w( src/core/lib/support/percent_encoding.h )
   s.files += %w( src/core/lib/support/stack_lockfree.h )
   s.files += %w( src/core/lib/support/string.h )
   s.files += %w( src/core/lib/support/string_windows.h )
@@ -118,6 +119,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/support/log_posix.c )
   s.files += %w( src/core/lib/support/log_windows.c )
   s.files += %w( src/core/lib/support/murmur_hash.c )
+  s.files += %w( src/core/lib/support/percent_encoding.c )
   s.files += %w( src/core/lib/support/slice.c )
   s.files += %w( src/core/lib/support/slice_buffer.c )
   s.files += %w( src/core/lib/support/stack_lockfree.c )
diff --git a/package.xml b/package.xml
index 613b5c6df4b..93210ee47be 100644
--- a/package.xml
+++ b/package.xml
@@ -98,6 +98,7 @@
     <file baseinstalldir="/" name="src/core/lib/support/block_annotate.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/env.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/murmur_hash.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/support/percent_encoding.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/stack_lockfree.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/string.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/string_windows.h" role="src" />
@@ -125,6 +126,7 @@
     <file baseinstalldir="/" name="src/core/lib/support/log_posix.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/log_windows.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/murmur_hash.c" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/support/percent_encoding.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/slice.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/slice_buffer.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/support/stack_lockfree.c" role="src" />
diff --git a/src/core/lib/support/percent_encoding.c b/src/core/lib/support/percent_encoding.c
new file mode 100644
index 00000000000..3c19f264f9f
--- /dev/null
+++ b/src/core/lib/support/percent_encoding.c
@@ -0,0 +1,180 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/lib/support/percent_encoding.h"
+
+#include <grpc/support/log.h>
+
+const uint8_t gpr_url_percent_encoding_unreserved_bytes[256 / 8] = {
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x60, 0xff, 0x03, 0xfe, 0xff, 0xff,
+    0x87, 0xfe, 0xff, 0xff, 0x47, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+const uint8_t gpr_compatible_percent_encoding_unreserved_bytes[256 / 8] = {
+    0x00, 0x00, 0x00, 0x00, 0xdf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+    0xff, 0xff, 0xff, 0xff, 0x7f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+static bool is_unreserved_character(uint8_t c,
+                                    const uint8_t *unreserved_bytes) {
+  return ((unreserved_bytes[c / 8] >> (c % 8)) & 1) != 0;
+}
+
+gpr_slice gpr_percent_encode_slice(gpr_slice slice,
+                                   const uint8_t *unreserved_bytes) {
+  static const uint8_t hex[] = "0123456789ABCDEF";
+
+  // first pass: count the number of bytes needed to output this string
+  size_t output_length = 0;
+  const uint8_t *slice_start = GPR_SLICE_START_PTR(slice);
+  const uint8_t *slice_end = GPR_SLICE_END_PTR(slice);
+  const uint8_t *p;
+  bool any_reserved_bytes = false;
+  for (p = slice_start; p < slice_end; p++) {
+    bool unres = is_unreserved_character(*p, unreserved_bytes);
+    output_length += unres ? 1 : 3;
+    any_reserved_bytes |= !unres;
+  }
+  // no unreserved bytes: return the string unmodified
+  if (!any_reserved_bytes) {
+    return gpr_slice_ref(slice);
+  }
+  // second pass: actually encode
+  gpr_slice out = gpr_slice_malloc(output_length);
+  uint8_t *q = GPR_SLICE_START_PTR(out);
+  for (p = slice_start; p < slice_end; p++) {
+    if (is_unreserved_character(*p, unreserved_bytes)) {
+      *q++ = *p;
+    } else {
+      *q++ = '%';
+      *q++ = hex[*p >> 4];
+      *q++ = hex[*p & 15];
+    }
+  }
+  GPR_ASSERT(q == GPR_SLICE_END_PTR(out));
+  return out;
+}
+
+static bool valid_hex(const uint8_t *p, const uint8_t *end) {
+  if (p >= end) return false;
+  return (*p >= '0' && *p <= '9') || (*p >= 'a' && *p <= 'f') ||
+         (*p >= 'A' && *p <= 'F');
+}
+
+static uint8_t dehex(uint8_t c) {
+  if (c >= '0' && c <= '9') return (uint8_t)(c - '0');
+  if (c >= 'A' && c <= 'F') return (uint8_t)(c - 'A' + 10);
+  if (c >= 'a' && c <= 'f') return (uint8_t)(c - 'a' + 10);
+  GPR_UNREACHABLE_CODE(return 255);
+}
+
+bool gpr_strict_percent_decode_slice(gpr_slice slice_in,
+                                     const uint8_t *unreserved_bytes,
+                                     gpr_slice *slice_out) {
+  const uint8_t *p = GPR_SLICE_START_PTR(slice_in);
+  const uint8_t *in_end = GPR_SLICE_END_PTR(slice_in);
+  size_t out_length = 0;
+  bool any_percent_encoded_stuff = false;
+  while (p != in_end) {
+    if (*p == '%') {
+      if (!valid_hex(++p, in_end)) return false;
+      if (!valid_hex(++p, in_end)) return false;
+      p++;
+      out_length++;
+      any_percent_encoded_stuff = true;
+    } else if (is_unreserved_character(*p, unreserved_bytes)) {
+      p++;
+      out_length++;
+    } else {
+      return false;
+    }
+  }
+  if (!any_percent_encoded_stuff) {
+    *slice_out = gpr_slice_ref(slice_in);
+    return true;
+  }
+  p = GPR_SLICE_START_PTR(slice_in);
+  *slice_out = gpr_slice_malloc(out_length);
+  uint8_t *q = GPR_SLICE_START_PTR(*slice_out);
+  while (p != in_end) {
+    if (*p == '%') {
+      *q++ = (uint8_t)(dehex(p[1]) << 4) | (dehex(p[2]));
+      p += 3;
+    } else {
+      *q++ = *p++;
+    }
+  }
+  GPR_ASSERT(q == GPR_SLICE_END_PTR(*slice_out));
+  return true;
+}
+
+gpr_slice gpr_permissive_percent_decode_slice(gpr_slice slice_in) {
+  const uint8_t *p = GPR_SLICE_START_PTR(slice_in);
+  const uint8_t *in_end = GPR_SLICE_END_PTR(slice_in);
+  size_t out_length = 0;
+  bool any_percent_encoded_stuff = false;
+  while (p != in_end) {
+    if (*p == '%') {
+      if (!valid_hex(p + 1, in_end) || !valid_hex(p + 2, in_end)) {
+        p++;
+        out_length++;
+      } else {
+        p += 3;
+        out_length++;
+        any_percent_encoded_stuff = true;
+      }
+    } else {
+      p++;
+      out_length++;
+    }
+  }
+  if (!any_percent_encoded_stuff) {
+    return gpr_slice_ref(slice_in);
+  }
+  p = GPR_SLICE_START_PTR(slice_in);
+  gpr_slice out = gpr_slice_malloc(out_length);
+  uint8_t *q = GPR_SLICE_START_PTR(out);
+  while (p != in_end) {
+    if (*p == '%') {
+      if (!valid_hex(p + 1, in_end) || !valid_hex(p + 2, in_end)) {
+        *q++ = *p++;
+      } else {
+        *q++ = (uint8_t)(dehex(p[1]) << 4) | (dehex(p[2]));
+        p += 3;
+      }
+    } else {
+      *q++ = *p++;
+    }
+  }
+  GPR_ASSERT(q == GPR_SLICE_END_PTR(out));
+  return out;
+}
diff --git a/src/core/lib/support/percent_encoding.h b/src/core/lib/support/percent_encoding.h
new file mode 100644
index 00000000000..000bf14ede4
--- /dev/null
+++ b/src/core/lib/support/percent_encoding.h
@@ -0,0 +1,78 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_SUPPORT_PERCENT_ENCODING_H
+#define GRPC_CORE_LIB_SUPPORT_PERCENT_ENCODING_H
+
+/* Percent encoding and decoding of slices.
+   Transforms arbitrary strings into safe-for-transmission strings by using
+   variants of percent encoding (RFC 3986).
+   Two major variants are supplied: one that strictly matches URL encoding,
+     and another which applies percent encoding only to non-http2 header
+     bytes (the 'compatible' variant) */
+
+#include <stdbool.h>
+
+#include <grpc/support/slice.h>
+
+/* URL percent encoding spec bitfield (usabel as 'unreserved_bytes' in
+   gpr_percent_encode_slice, gpr_strict_percent_decode_slice).
+   Flags [A-Za-z0-9-_.~] as unreserved bytes for the percent encoding routines
+   */
+extern const uint8_t gpr_url_percent_encoding_unreserved_bytes[256 / 8];
+/* URL percent encoding spec bitfield (usabel as 'unreserved_bytes' in
+   gpr_percent_encode_slice, gpr_strict_percent_decode_slice).
+   Flags ascii7 non-control characters excluding '%' as unreserved bytes for the
+   percent encoding routines */
+extern const uint8_t gpr_compatible_percent_encoding_unreserved_bytes[256 / 8];
+
+/* Percent-encode a slice, returning the new slice (this cannot fail):
+   unreserved_bytes is a bitfield indicating which bytes are considered
+   unreserved and thus do not need percent encoding */
+gpr_slice gpr_percent_encode_slice(gpr_slice slice,
+                                   const uint8_t *unreserved_bytes);
+/* Percent-decode a slice, strictly.
+   If the input is legal (contains no unreserved bytes, and legal % encodings),
+   returns true and sets *slice_out to the decoded slice.
+   If the input is not legal, returns false and leaves *slice_out untouched.
+   unreserved_bytes is a bitfield indicating which bytes are considered
+   unreserved and thus do not need percent encoding */
+bool gpr_strict_percent_decode_slice(gpr_slice slice_in,
+                                     const uint8_t *unreserved_bytes,
+                                     gpr_slice *slice_out);
+/* Percent-decode a slice, permissively.
+   If a % triplet can not be decoded, pass it through verbatim.
+   This cannot fail. */
+gpr_slice gpr_permissive_percent_decode_slice(gpr_slice slice_in);
+
+#endif /* GRPC_CORE_LIB_SUPPORT_PERCENT_ENCODING_H */
diff --git a/src/python/grpcio/grpc_core_dependencies.py b/src/python/grpcio/grpc_core_dependencies.py
index 725134c3a47..be7f30c29b3 100644
--- a/src/python/grpcio/grpc_core_dependencies.py
+++ b/src/python/grpcio/grpc_core_dependencies.py
@@ -51,6 +51,7 @@ CORE_SOURCE_FILES = [
   'src/core/lib/support/log_posix.c',
   'src/core/lib/support/log_windows.c',
   'src/core/lib/support/murmur_hash.c',
+  'src/core/lib/support/percent_encoding.c',
   'src/core/lib/support/slice.c',
   'src/core/lib/support/slice_buffer.c',
   'src/core/lib/support/stack_lockfree.c',
diff --git a/test/core/support/percent_decode_corpus/04cb8ccc553f9b2f5e52c421aff6d1c954d3dae6 b/test/core/support/percent_decode_corpus/04cb8ccc553f9b2f5e52c421aff6d1c954d3dae6
new file mode 100644
index 00000000000..a0c7605580a
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/04cb8ccc553f9b2f5e52c421aff6d1c954d3dae6
@@ -0,0 +1 @@
+:Ê%cE'yzŠ
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/0dd8f3a63745b3a2d39791559b5c1b311447b537 b/test/core/support/percent_decode_corpus/0dd8f3a63745b3a2d39791559b5c1b311447b537
new file mode 100644
index 00000000000..8b36124b3fb
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/0dd8f3a63745b3a2d39791559b5c1b311447b537
@@ -0,0 +1 @@
+x;x_%C88
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/17eeaca784409adbe43365c32ac87915d736bba3 b/test/core/support/percent_decode_corpus/17eeaca784409adbe43365c32ac87915d736bba3
new file mode 100644
index 00000000000..ea02afac49b
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/17eeaca784409adbe43365c32ac87915d736bba3
@@ -0,0 +1,2 @@
+xxyyz%øyzŠ[zxy'z
+
diff --git a/test/core/support/percent_decode_corpus/2040c1ff65f52a7ae668c2c8f324de5dacc9d695 b/test/core/support/percent_decode_corpus/2040c1ff65f52a7ae668c2c8f324de5dacc9d695
new file mode 100644
index 00000000000..9e9b466b2f7
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/2040c1ff65f52a7ae668c2c8f324de5dacc9d695
@@ -0,0 +1 @@
+xx;x_%;:Ê%C)x_%C88c8E'yzŠ8
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/26b0d1da23027ae54db96e125e4a9e98842d77fb b/test/core/support/percent_decode_corpus/26b0d1da23027ae54db96e125e4a9e98842d77fb
new file mode 100644
index 00000000000..88c739ecaa1
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/26b0d1da23027ae54db96e125e4a9e98842d77fb
@@ -0,0 +1 @@
+))'x;x_%C88xy(Pyz)
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/2a089c0db45acdb4c6ed8e7ff81ca7235792c0b9 b/test/core/support/percent_decode_corpus/2a089c0db45acdb4c6ed8e7ff81ca7235792c0b9
new file mode 100644
index 00000000000..5e6f546ff5c
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/2a089c0db45acdb4c6ed8e7ff81ca7235792c0b9
@@ -0,0 +1 @@
+_x;x)x;x_x;x_%88%8888:
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/35b7b3bc3a740d5c3abca0d75b53f0e1e1ee998a b/test/core/support/percent_decode_corpus/35b7b3bc3a740d5c3abca0d75b53f0e1e1ee998a
new file mode 100644
index 00000000000..71d688b694e
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/35b7b3bc3a740d5c3abca0d75b53f0e1e1ee998a
@@ -0,0 +1 @@
+x8
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/36367ba1adba47a1cbc3a88707fde8cc7abdc248 b/test/core/support/percent_decode_corpus/36367ba1adba47a1cbc3a88707fde8cc7abdc248
new file mode 100644
index 00000000000..5a89a07ba76
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/36367ba1adba47a1cbc3a88707fde8cc7abdc248
@@ -0,0 +1 @@
+x);x(_%88x;x_%88
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/39c2ba51548a0beaf0d6d1164531f1447dc311b5 b/test/core/support/percent_decode_corpus/39c2ba51548a0beaf0d6d1164531f1447dc311b5
new file mode 100644
index 00000000000..cfa2be994fb
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/39c2ba51548a0beaf0d6d1164531f1447dc311b5
@@ -0,0 +1 @@
+)x;x_x;x_%88%88:
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/56d08fea787c041395c6697ce26cfbc0decbe688 b/test/core/support/percent_decode_corpus/56d08fea787c041395c6697ce26cfbc0decbe688
new file mode 100644
index 00000000000..c1ddf65acd2
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/56d08fea787c041395c6697ce26cfbc0decbe688
@@ -0,0 +1 @@
+%cyzŠ
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/678d981fdabb9f0d6640235cf1719dd1e1e66ae9 b/test/core/support/percent_decode_corpus/678d981fdabb9f0d6640235cf1719dd1e1e66ae9
new file mode 100644
index 00000000000..dc427d1e120
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/678d981fdabb9f0d6640235cf1719dd1e1e66ae9
@@ -0,0 +1 @@
+%øyzŠ
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/68751961609ec010565de0aa87521dcbf0722c5d b/test/core/support/percent_decode_corpus/68751961609ec010565de0aa87521dcbf0722c5d
new file mode 100644
index 00000000000..154449d0efe
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/68751961609ec010565de0aa87521dcbf0722c5d
@@ -0,0 +1 @@
+Ê:%Ec
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/7875c06c6f03c9aa2f8e9c59f8d8957c8a32e759 b/test/core/support/percent_decode_corpus/7875c06c6f03c9aa2f8e9c59f8d8957c8a32e759
new file mode 100644
index 00000000000..841ced83c3f
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/7875c06c6f03c9aa2f8e9c59f8d8957c8a32e759
@@ -0,0 +1,2 @@
+xxyyz!úyzŠ[zxy'zyz
+Š
diff --git a/test/core/support/percent_decode_corpus/7b302090e090a5829b6d1dd7be30bd4e36a7e60f b/test/core/support/percent_decode_corpus/7b302090e090a5829b6d1dd7be30bd4e36a7e60f
new file mode 100644
index 00000000000..6790bc27984
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/7b302090e090a5829b6d1dd7be30bd4e36a7e60f
@@ -0,0 +1 @@
+x;:Ê%)x_%C8cE'yzŠ8
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/875e1022169c9e4c541a9ad894e69e989df22ba1 b/test/core/support/percent_decode_corpus/875e1022169c9e4c541a9ad894e69e989df22ba1
new file mode 100644
index 00000000000..1625d0a1aed
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/875e1022169c9e4c541a9ad894e69e989df22ba1
@@ -0,0 +1 @@
+x;x_%88
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/8c1051ce066f5a26de9a9d133180621d0da957b4 b/test/core/support/percent_decode_corpus/8c1051ce066f5a26de9a9d133180621d0da957b4
new file mode 100644
index 00000000000..125c330b3e4
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/8c1051ce066f5a26de9a9d133180621d0da957b4
@@ -0,0 +1 @@
+)))'x;x_%C88)'x;x_%C89xyyzxyyz)
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/8e084e628ab83a18ac7ca7cb3506525263655c63 b/test/core/support/percent_decode_corpus/8e084e628ab83a18ac7ca7cb3506525263655c63
new file mode 100644
index 00000000000..6e6f08cb07f
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/8e084e628ab83a18ac7ca7cb3506525263655c63
@@ -0,0 +1 @@
+))'x;x_%C88xyyz)
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/9d316c4675f40ddccaf8f1cc7aea94170b1e4223 b/test/core/support/percent_decode_corpus/9d316c4675f40ddccaf8f1cc7aea94170b1e4223
new file mode 100644
index 00000000000..ab4a1c7657b
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/9d316c4675f40ddccaf8f1cc7aea94170b1e4223
@@ -0,0 +1 @@
+x%8
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/ad1c7c11d18a7d116e2c2ef4d4c5afb1270836ae b/test/core/support/percent_decode_corpus/ad1c7c11d18a7d116e2c2ef4d4c5afb1270836ae
new file mode 100644
index 00000000000..4ac1945a847
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/ad1c7c11d18a7d116e2c2ef4d4c5afb1270836ae
@@ -0,0 +1 @@
+x);x(_%88x;x_xxyyz
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/b471f94aa4facf502e622e4a248f1ba4063ae681 b/test/core/support/percent_decode_corpus/b471f94aa4facf502e622e4a248f1ba4063ae681
new file mode 100644
index 00000000000..5c673ae28a7
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/b471f94aa4facf502e622e4a248f1ba4063ae681
@@ -0,0 +1 @@
+Ê%ccyzyzŠ
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/bf52ece030f16136d46e0dc97f58d60a0d8a1f0b b/test/core/support/percent_decode_corpus/bf52ece030f16136d46e0dc97f58d60a0d8a1f0b
new file mode 100644
index 00000000000..e478275ed4f
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/bf52ece030f16136d46e0dc97f58d60a0d8a1f0b
@@ -0,0 +1,2 @@
+)'xyyz!úyzŠ[zxÊ%ccyzyzy'z*zŠ
+Š
diff --git a/test/core/support/percent_decode_corpus/d5b2a7177339ba2b7ce2f60e5f4459bef1e72758 b/test/core/support/percent_decode_corpus/d5b2a7177339ba2b7ce2f60e5f4459bef1e72758
new file mode 100644
index 00000000000..c73cbfe8aff
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/d5b2a7177339ba2b7ce2f60e5f4459bef1e72758
@@ -0,0 +1,2 @@
+)'xyyz)úyzŠ[zxÊ%cCyzyzy'z*zŠ
+Š
diff --git a/test/core/support/percent_decode_corpus/de867b64c54a7ed773dc611fc5cd2f17c5433113 b/test/core/support/percent_decode_corpus/de867b64c54a7ed773dc611fc5cd2f17c5433113
new file mode 100644
index 00000000000..f9f7246e9c9
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/de867b64c54a7ed773dc611fc5cd2f17c5433113
@@ -0,0 +1,2 @@
+xxyyz%%øyzŠ[zxy'zyz
+Š
diff --git a/test/core/support/percent_decode_corpus/e3948dbe004950591630dd5c52f4e0fcbd5e388a b/test/core/support/percent_decode_corpus/e3948dbe004950591630dd5c52f4e0fcbd5e388a
new file mode 100644
index 00000000000..83ac46d8337
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/e3948dbe004950591630dd5c52f4e0fcbd5e388a
@@ -0,0 +1 @@
+Ê:%Dx;:Ê%)x_%C8cc
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/e7064f0b80f61dbc65915311032d27baa569ae2a b/test/core/support/percent_decode_corpus/e7064f0b80f61dbc65915311032d27baa569ae2a
new file mode 100644
index 00000000000..e8a0f87653d
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/e7064f0b80f61dbc65915311032d27baa569ae2a
@@ -0,0 +1 @@
+)
\ No newline at end of file
diff --git a/test/core/support/percent_decode_corpus/xyz b/test/core/support/percent_decode_corpus/xyz
new file mode 100644
index 00000000000..cd470e61900
--- /dev/null
+++ b/test/core/support/percent_decode_corpus/xyz
@@ -0,0 +1 @@
+xyz
diff --git a/test/core/support/percent_decode_fuzzer.c b/test/core/support/percent_decode_fuzzer.c
new file mode 100644
index 00000000000..3e02980e05e
--- /dev/null
+++ b/test/core/support/percent_decode_fuzzer.c
@@ -0,0 +1,66 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include "src/core/lib/support/percent_encoding.h"
+#include "test/core/util/memory_counters.h"
+
+bool squelch = true;
+bool leak_check = true;
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  struct grpc_memory_counters counters;
+  grpc_memory_counters_init();
+  gpr_slice input = gpr_slice_from_copied_buffer((const char *)data, size);
+  gpr_slice output;
+  if (gpr_strict_percent_decode_slice(
+          input, gpr_url_percent_encoding_unreserved_bytes, &output)) {
+    gpr_slice_unref(output);
+  }
+  if (gpr_strict_percent_decode_slice(
+          input, gpr_compatible_percent_encoding_unreserved_bytes, &output)) {
+    gpr_slice_unref(output);
+  }
+  gpr_slice_unref(gpr_permissive_percent_decode_slice(input));
+  gpr_slice_unref(input);
+  counters = grpc_memory_counters_snapshot();
+  grpc_memory_counters_destroy();
+  GPR_ASSERT(counters.total_size_relative == 0);
+  return 0;
+}
diff --git a/test/core/support/percent_encode_corpus/0d3ee7fa54e6c66103965fd4409b044ba7db6c3f b/test/core/support/percent_encode_corpus/0d3ee7fa54e6c66103965fd4409b044ba7db6c3f
new file mode 100644
index 00000000000..d09c4a039c0
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/0d3ee7fa54e6c66103965fd4409b044ba7db6c3f
@@ -0,0 +1,3 @@
+_x;7y
+xyz')S)xy-zý
+Æ*
\ No newline at end of file
diff --git a/test/core/support/percent_encode_corpus/2e7ccf75e27b9501e3b28cf1c50ed0c45ab7c226 b/test/core/support/percent_encode_corpus/2e7ccf75e27b9501e3b28cf1c50ed0c45ab7c226
new file mode 100644
index 00000000000..4d0c38d0e27
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/2e7ccf75e27b9501e3b28cf1c50ed0c45ab7c226
@@ -0,0 +1 @@
+xyx
\ No newline at end of file
diff --git a/test/core/support/percent_encode_corpus/55bb859f3942c462b03b7cbcf22ab4a0ac9705cf b/test/core/support/percent_encode_corpus/55bb859f3942c462b03b7cbcf22ab4a0ac9705cf
new file mode 100644
index 00000000000..fc6e93342a6
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/55bb859f3942c462b03b7cbcf22ab4a0ac9705cf
@@ -0,0 +1 @@
+.yx.yxxxyzxyyzxy
\ No newline at end of file
diff --git a/test/core/support/percent_encode_corpus/56070cecd54c845b6d4334953b17b712eb000d93 b/test/core/support/percent_encode_corpus/56070cecd54c845b6d4334953b17b712eb000d93
new file mode 100644
index 00000000000..6823c73f767
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/56070cecd54c845b6d4334953b17b712eb000d93
@@ -0,0 +1 @@
+xyrxyxyzxxyzxyzxyxyy
\ No newline at end of file
diff --git a/test/core/support/percent_encode_corpus/61f50e891bf7ff5eb7a7af206f1e25d77f8756e7 b/test/core/support/percent_encode_corpus/61f50e891bf7ff5eb7a7af206f1e25d77f8756e7
new file mode 100644
index 00000000000..a65cbb4d5be
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/61f50e891bf7ff5eb7a7af206f1e25d77f8756e7
@@ -0,0 +1,3 @@
+xy
+xyz
+)S-Æþ
\ No newline at end of file
diff --git a/test/core/support/percent_encode_corpus/6e0c60cefc704c7940e475a87dd9ae423061cb5a b/test/core/support/percent_encode_corpus/6e0c60cefc704c7940e475a87dd9ae423061cb5a
new file mode 100644
index 00000000000..8d031d7e2d8
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/6e0c60cefc704c7940e475a87dd9ae423061cb5a
@@ -0,0 +1,3 @@
+xy
+xyz
+)S)Æ*
\ No newline at end of file
diff --git a/test/core/support/percent_encode_corpus/7271ebcc6d22a0f186f7bc3c1973a7ed1bec8d8e b/test/core/support/percent_encode_corpus/7271ebcc6d22a0f186f7bc3c1973a7ed1bec8d8e
new file mode 100644
index 00000000000..4d82ca3953d
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/7271ebcc6d22a0f186f7bc3c1973a7ed1bec8d8e
@@ -0,0 +1,4 @@
+x;7y
+xyz
+)S)xyz
+Æ*
\ No newline at end of file
diff --git a/test/core/support/percent_encode_corpus/74c83ece3e2920a67593a9be9c82468f16cbb969 b/test/core/support/percent_encode_corpus/74c83ece3e2920a67593a9be9c82468f16cbb969
new file mode 100644
index 00000000000..bb7f4ae07e5
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/74c83ece3e2920a67593a9be9c82468f16cbb969
@@ -0,0 +1 @@
+xyzxy
\ No newline at end of file
diff --git a/test/core/support/percent_encode_corpus/98e004fd2a9f141a7a019720820080e12d637c06 b/test/core/support/percent_encode_corpus/98e004fd2a9f141a7a019720820080e12d637c06
new file mode 100644
index 00000000000..50879d0f375
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/98e004fd2a9f141a7a019720820080e12d637c06
@@ -0,0 +1,3 @@
+xy
+xz
+)Sxy-Æzx_yþ
\ No newline at end of file
diff --git a/test/core/support/percent_encode_corpus/ba2c1e98227aa21ea3bb2ca4d0e504119717da8b b/test/core/support/percent_encode_corpus/ba2c1e98227aa21ea3bb2ca4d0e504119717da8b
new file mode 100644
index 00000000000..dc1ab9bfc2d
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/ba2c1e98227aa21ea3bb2ca4d0e504119717da8b
@@ -0,0 +1,3 @@
+_x;7y
+xyz')S)xyz
+Æ*
\ No newline at end of file
diff --git a/test/core/support/percent_encode_corpus/c16b9fd45370d4afb5d3ebd307a6e263c25ffd45 b/test/core/support/percent_encode_corpus/c16b9fd45370d4afb5d3ebd307a6e263c25ffd45
new file mode 100644
index 00000000000..3476e0b70bf
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/c16b9fd45370d4afb5d3ebd307a6e263c25ffd45
@@ -0,0 +1,2 @@
+xyz
+)S
\ No newline at end of file
diff --git a/test/core/support/percent_encode_corpus/d58c3cd4eab9b6d2343abfa1c25c90a383fe0ec3 b/test/core/support/percent_encode_corpus/d58c3cd4eab9b6d2343abfa1c25c90a383fe0ec3
new file mode 100644
index 00000000000..822d50abf8d
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/d58c3cd4eab9b6d2343abfa1c25c90a383fe0ec3
@@ -0,0 +1 @@
+.yx
\ No newline at end of file
diff --git a/test/core/support/percent_encode_corpus/e2619218ede30d2b7b8ecd601a9f0ae754b728b4 b/test/core/support/percent_encode_corpus/e2619218ede30d2b7b8ecd601a9f0ae754b728b4
new file mode 100644
index 00000000000..101639c93d6
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/e2619218ede30d2b7b8ecd601a9f0ae754b728b4
@@ -0,0 +1,4 @@
+x;y
+xyz
+)S)xyz
+Æ*
\ No newline at end of file
diff --git a/test/core/support/percent_encode_corpus/f93b3653e453f0e3eea3198001be6ce46e64bd21 b/test/core/support/percent_encode_corpus/f93b3653e453f0e3eea3198001be6ce46e64bd21
new file mode 100644
index 00000000000..6e07ab342fe
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/f93b3653e453f0e3eea3198001be6ce46e64bd21
@@ -0,0 +1,5 @@
+x;y
+xøyz
+)S)xyz
+Æ.y~
+)S
\ No newline at end of file
diff --git a/test/core/support/percent_encode_corpus/fd41d029c7682ad3d1c40a9fd017a4c85b673a54 b/test/core/support/percent_encode_corpus/fd41d029c7682ad3d1c40a9fd017a4c85b673a54
new file mode 100644
index 00000000000..13d7fab5968
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/fd41d029c7682ad3d1c40a9fd017a4c85b673a54
@@ -0,0 +1,3 @@
+xy
+xyz
+)S)S
\ No newline at end of file
diff --git a/test/core/support/percent_encode_corpus/xyz b/test/core/support/percent_encode_corpus/xyz
new file mode 100644
index 00000000000..cd470e61900
--- /dev/null
+++ b/test/core/support/percent_encode_corpus/xyz
@@ -0,0 +1 @@
+xyz
diff --git a/test/core/support/percent_encode_fuzzer.c b/test/core/support/percent_encode_fuzzer.c
new file mode 100644
index 00000000000..c9548232b5f
--- /dev/null
+++ b/test/core/support/percent_encode_fuzzer.c
@@ -0,0 +1,73 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include "src/core/lib/support/percent_encoding.h"
+#include "test/core/util/memory_counters.h"
+
+bool squelch = true;
+bool leak_check = true;
+
+static void test(const uint8_t *data, size_t size, const uint8_t *dict) {
+  struct grpc_memory_counters counters;
+  grpc_memory_counters_init();
+  gpr_slice input = gpr_slice_from_copied_buffer((const char *)data, size);
+  gpr_slice output = gpr_percent_encode_slice(input, dict);
+  gpr_slice decoded_output;
+  // encoder must always produce decodable output
+  GPR_ASSERT(gpr_strict_percent_decode_slice(output, dict, &decoded_output));
+  gpr_slice permissive_decoded_output =
+      gpr_permissive_percent_decode_slice(output);
+  // and decoded output must always match the input
+  GPR_ASSERT(gpr_slice_cmp(input, decoded_output) == 0);
+  GPR_ASSERT(gpr_slice_cmp(input, permissive_decoded_output) == 0);
+  gpr_slice_unref(input);
+  gpr_slice_unref(output);
+  gpr_slice_unref(decoded_output);
+  gpr_slice_unref(permissive_decoded_output);
+  counters = grpc_memory_counters_snapshot();
+  grpc_memory_counters_destroy();
+  GPR_ASSERT(counters.total_size_relative == 0);
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  test(data, size, gpr_url_percent_encoding_unreserved_bytes);
+  test(data, size, gpr_compatible_percent_encoding_unreserved_bytes);
+  return 0;
+}
diff --git a/test/core/support/percent_encoding_test.c b/test/core/support/percent_encoding_test.c
new file mode 100644
index 00000000000..ab5f3f2d14d
--- /dev/null
+++ b/test/core/support/percent_encoding_test.c
@@ -0,0 +1,157 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/lib/support/percent_encoding.h"
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include "src/core/lib/support/string.h"
+#include "test/core/util/test_config.h"
+
+#define TEST_VECTOR(raw, encoded, dict) \
+  test_vector(raw, sizeof(raw) - 1, encoded, sizeof(encoded) - 1, dict)
+
+#define TEST_NONCONFORMANT_VECTOR(encoded, permissive_unencoded, dict) \
+  test_nonconformant_vector(encoded, sizeof(encoded) - 1,              \
+                            permissive_unencoded,                      \
+                            sizeof(permissive_unencoded) - 1, dict)
+
+static void test_vector(const char *raw, size_t raw_length, const char *encoded,
+                        size_t encoded_length, const uint8_t *dict) {
+  char *raw_msg = gpr_dump(raw, raw_length, GPR_DUMP_HEX | GPR_DUMP_ASCII);
+  char *encoded_msg =
+      gpr_dump(encoded, encoded_length, GPR_DUMP_HEX | GPR_DUMP_ASCII);
+  gpr_log(GPR_DEBUG, "Trial:\nraw = %s\nencoded = %s", raw_msg, encoded_msg);
+  gpr_free(raw_msg);
+  gpr_free(encoded_msg);
+
+  gpr_slice raw_slice = gpr_slice_from_copied_buffer(raw, raw_length);
+  gpr_slice encoded_slice =
+      gpr_slice_from_copied_buffer(encoded, encoded_length);
+  gpr_slice raw2encoded_slice = gpr_percent_encode_slice(raw_slice, dict);
+  gpr_slice encoded2raw_slice;
+  GPR_ASSERT(
+      gpr_strict_percent_decode_slice(encoded_slice, dict, &encoded2raw_slice));
+  gpr_slice encoded2raw_permissive_slice =
+      gpr_permissive_percent_decode_slice(encoded_slice);
+
+  char *raw2encoded_msg =
+      gpr_dump_slice(raw2encoded_slice, GPR_DUMP_HEX | GPR_DUMP_ASCII);
+  char *encoded2raw_msg =
+      gpr_dump_slice(encoded2raw_slice, GPR_DUMP_HEX | GPR_DUMP_ASCII);
+  char *encoded2raw_permissive_msg = gpr_dump_slice(
+      encoded2raw_permissive_slice, GPR_DUMP_HEX | GPR_DUMP_ASCII);
+  gpr_log(GPR_DEBUG,
+          "Result:\nraw2encoded = %s\nencoded2raw = %s\nencoded2raw_permissive "
+          "= %s",
+          raw2encoded_msg, encoded2raw_msg, encoded2raw_permissive_msg);
+  gpr_free(raw2encoded_msg);
+  gpr_free(encoded2raw_msg);
+  gpr_free(encoded2raw_permissive_msg);
+
+  GPR_ASSERT(0 == gpr_slice_cmp(raw_slice, encoded2raw_slice));
+  GPR_ASSERT(0 == gpr_slice_cmp(raw_slice, encoded2raw_permissive_slice));
+  GPR_ASSERT(0 == gpr_slice_cmp(encoded_slice, raw2encoded_slice));
+
+  gpr_slice_unref(encoded2raw_slice);
+  gpr_slice_unref(encoded2raw_permissive_slice);
+  gpr_slice_unref(raw2encoded_slice);
+  gpr_slice_unref(raw_slice);
+  gpr_slice_unref(encoded_slice);
+}
+
+static void test_nonconformant_vector(const char *encoded,
+                                      size_t encoded_length,
+                                      const char *permissive_unencoded,
+                                      size_t permissive_unencoded_length,
+                                      const uint8_t *dict) {
+  char *permissive_unencoded_msg =
+      gpr_dump(permissive_unencoded, permissive_unencoded_length,
+               GPR_DUMP_HEX | GPR_DUMP_ASCII);
+  char *encoded_msg =
+      gpr_dump(encoded, encoded_length, GPR_DUMP_HEX | GPR_DUMP_ASCII);
+  gpr_log(GPR_DEBUG, "Trial:\nraw = %s\nencoded = %s", permissive_unencoded_msg,
+          encoded_msg);
+  gpr_free(permissive_unencoded_msg);
+  gpr_free(encoded_msg);
+
+  gpr_slice permissive_unencoded_slice = gpr_slice_from_copied_buffer(
+      permissive_unencoded, permissive_unencoded_length);
+  gpr_slice encoded_slice =
+      gpr_slice_from_copied_buffer(encoded, encoded_length);
+  gpr_slice encoded2raw_slice;
+  GPR_ASSERT(!gpr_strict_percent_decode_slice(encoded_slice, dict,
+                                              &encoded2raw_slice));
+  gpr_slice encoded2raw_permissive_slice =
+      gpr_permissive_percent_decode_slice(encoded_slice);
+
+  char *encoded2raw_permissive_msg = gpr_dump_slice(
+      encoded2raw_permissive_slice, GPR_DUMP_HEX | GPR_DUMP_ASCII);
+  gpr_log(GPR_DEBUG, "Result:\nencoded2raw_permissive = %s",
+          encoded2raw_permissive_msg);
+  gpr_free(encoded2raw_permissive_msg);
+
+  GPR_ASSERT(0 == gpr_slice_cmp(permissive_unencoded_slice,
+                                encoded2raw_permissive_slice));
+
+  gpr_slice_unref(permissive_unencoded_slice);
+  gpr_slice_unref(encoded2raw_permissive_slice);
+  gpr_slice_unref(encoded_slice);
+}
+
+int main(int argc, char **argv) {
+  grpc_test_init(argc, argv);
+  TEST_VECTOR(
+      "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.~",
+      "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.~",
+      gpr_url_percent_encoding_unreserved_bytes);
+  TEST_VECTOR("\x00", "%00", gpr_url_percent_encoding_unreserved_bytes);
+  TEST_VECTOR("\x01", "%01", gpr_url_percent_encoding_unreserved_bytes);
+  TEST_VECTOR("a b", "a%20b", gpr_url_percent_encoding_unreserved_bytes);
+  TEST_VECTOR(" b", "%20b", gpr_url_percent_encoding_unreserved_bytes);
+  TEST_VECTOR("a b", "a b", gpr_compatible_percent_encoding_unreserved_bytes);
+  TEST_VECTOR(" b", " b", gpr_compatible_percent_encoding_unreserved_bytes);
+  TEST_VECTOR("\x0f", "%0F", gpr_url_percent_encoding_unreserved_bytes);
+  TEST_VECTOR("\xff", "%FF", gpr_url_percent_encoding_unreserved_bytes);
+  TEST_VECTOR("\xee", "%EE", gpr_url_percent_encoding_unreserved_bytes);
+  TEST_NONCONFORMANT_VECTOR("%", "%",
+                            gpr_url_percent_encoding_unreserved_bytes);
+  TEST_NONCONFORMANT_VECTOR("%A", "%A",
+                            gpr_url_percent_encoding_unreserved_bytes);
+  TEST_NONCONFORMANT_VECTOR("%AG", "%AG",
+                            gpr_url_percent_encoding_unreserved_bytes);
+  TEST_NONCONFORMANT_VECTOR("\0", "\0",
+                            gpr_url_percent_encoding_unreserved_bytes);
+  return 0;
+}
diff --git a/tools/codegen/core/gen_percent_encoding_tables.c b/tools/codegen/core/gen_percent_encoding_tables.c
new file mode 100644
index 00000000000..93f30deeb33
--- /dev/null
+++ b/tools/codegen/core/gen_percent_encoding_tables.c
@@ -0,0 +1,84 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+/* generates constant table for metadata.c */
+
+#include <stdio.h>
+#include <string.h>
+
+static unsigned char legal_bits[256 / 8];
+
+static void legal(int x) {
+  int byte = x / 8;
+  int bit = x % 8;
+  /* NB: the following integer arithmetic operation needs to be in its
+   * expanded form due to the "integral promotion" performed (see section
+   * 3.2.1.1 of the C89 draft standard). A cast to the smaller container type
+   * is then required to avoid the compiler warning */
+  legal_bits[byte] =
+      (unsigned char)((legal_bits[byte] | (unsigned char)(1 << bit)));
+}
+
+static void dump(const char *name) {
+  int i;
+
+  printf("const uint8_t %s[256/8] = ", name);
+  for (i = 0; i < 256 / 8; i++)
+    printf("%c 0x%02x", i ? ',' : '{', legal_bits[i]);
+  printf(" };\n");
+}
+
+static void clear(void) { memset(legal_bits, 0, sizeof(legal_bits)); }
+
+int main(void) {
+  int i;
+
+  clear();
+  for (i = 'a'; i <= 'z'; i++) legal(i);
+  for (i = 'A'; i <= 'Z'; i++) legal(i);
+  for (i = '0'; i <= '9'; i++) legal(i);
+  legal('-');
+  legal('_');
+  legal('.');
+  legal('~');
+  dump("gpr_url_percent_encoding_unreserved_bytes");
+
+  clear();
+  for (i = 32; i <= 126; i++) {
+    if (i == '%') continue;
+    legal(i);
+  }
+  dump("gpr_compatible_percent_encoding_unreserved_bytes");
+
+  return 0;
+}
diff --git a/tools/doxygen/Doxyfile.core.internal b/tools/doxygen/Doxyfile.core.internal
index 7d279ed464e..02590db4214 100644
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@@ -1186,6 +1186,7 @@ src/core/lib/support/backoff.h \
 src/core/lib/support/block_annotate.h \
 src/core/lib/support/env.h \
 src/core/lib/support/murmur_hash.h \
+src/core/lib/support/percent_encoding.h \
 src/core/lib/support/stack_lockfree.h \
 src/core/lib/support/string.h \
 src/core/lib/support/string_windows.h \
@@ -1213,6 +1214,7 @@ src/core/lib/support/log_linux.c \
 src/core/lib/support/log_posix.c \
 src/core/lib/support/log_windows.c \
 src/core/lib/support/murmur_hash.c \
+src/core/lib/support/percent_encoding.c \
 src/core/lib/support/slice.c \
 src/core/lib/support/slice_buffer.c \
 src/core/lib/support/stack_lockfree.c \
diff --git a/tools/fuzzer/runners/percent_decode_fuzzer.sh b/tools/fuzzer/runners/percent_decode_fuzzer.sh
new file mode 100644
index 00000000000..5a47fa222cf
--- /dev/null
+++ b/tools/fuzzer/runners/percent_decode_fuzzer.sh
@@ -0,0 +1,45 @@
+#!/bin/bash
+# Copyright 2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+
+flags="-max_total_time=$runtime -artifact_prefix=fuzzer_output/ -max_len=32 -timeout=120"
+
+
+if [ "$jobs" != "1" ]
+then
+  flags="-jobs=$jobs -workers=$jobs $flags"
+fi
+
+if [ "$config" == "asan-trace-cmp" ]
+then
+  flags="-use_traces=1 $flags"
+fi
+
+bins/$config/percent_decode_fuzzer $flags fuzzer_output test/core/support/percent_decode_corpus
diff --git a/tools/fuzzer/runners/percent_encode_fuzzer.sh b/tools/fuzzer/runners/percent_encode_fuzzer.sh
new file mode 100644
index 00000000000..8136ef8be9a
--- /dev/null
+++ b/tools/fuzzer/runners/percent_encode_fuzzer.sh
@@ -0,0 +1,45 @@
+#!/bin/bash
+# Copyright 2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+
+flags="-max_total_time=$runtime -artifact_prefix=fuzzer_output/ -max_len=32 -timeout=120"
+
+
+if [ "$jobs" != "1" ]
+then
+  flags="-jobs=$jobs -workers=$jobs $flags"
+fi
+
+if [ "$config" == "asan-trace-cmp" ]
+then
+  flags="-use_traces=1 $flags"
+fi
+
+bins/$config/percent_encode_fuzzer $flags fuzzer_output test/core/support/percent_encode_corpus
diff --git a/tools/run_tests/sources_and_headers.json b/tools/run_tests/sources_and_headers.json
index a9cc40325bc..9f74a553721 100644
--- a/tools/run_tests/sources_and_headers.json
+++ b/tools/run_tests/sources_and_headers.json
@@ -485,6 +485,17 @@
     "third_party": false, 
     "type": "target"
   }, 
+  {
+    "deps": [], 
+    "headers": [], 
+    "language": "c", 
+    "name": "gen_percent_encoding_tables", 
+    "src": [
+      "tools/codegen/core/gen_percent_encoding_tables.c"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
   {
     "deps": [
       "gpr", 
@@ -613,6 +624,20 @@
     "third_party": false, 
     "type": "target"
   }, 
+  {
+    "deps": [
+      "gpr", 
+      "gpr_test_util"
+    ], 
+    "headers": [], 
+    "language": "c", 
+    "name": "gpr_percent_encoding_test", 
+    "src": [
+      "test/core/support/percent_encoding_test.c"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
   {
     "deps": [
       "gpr", 
@@ -1449,6 +1474,38 @@
     "third_party": false, 
     "type": "target"
   }, 
+  {
+    "deps": [
+      "gpr", 
+      "gpr_test_util", 
+      "grpc", 
+      "grpc_test_util"
+    ], 
+    "headers": [], 
+    "language": "c", 
+    "name": "percent_decode_fuzzer", 
+    "src": [
+      "test/core/support/percent_decode_fuzzer.c"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
+  {
+    "deps": [
+      "gpr", 
+      "gpr_test_util", 
+      "grpc", 
+      "grpc_test_util"
+    ], 
+    "headers": [], 
+    "language": "c", 
+    "name": "percent_encode_fuzzer", 
+    "src": [
+      "test/core/support/percent_encode_fuzzer.c"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
   {
     "deps": [
       "gpr", 
@@ -4192,6 +4249,40 @@
     "third_party": false, 
     "type": "target"
   }, 
+  {
+    "deps": [
+      "gpr", 
+      "gpr_test_util", 
+      "grpc", 
+      "grpc_test_util"
+    ], 
+    "headers": [], 
+    "language": "c", 
+    "name": "percent_decode_fuzzer_one_entry", 
+    "src": [
+      "test/core/support/percent_decode_fuzzer.c", 
+      "test/core/util/one_corpus_entry_fuzzer.c"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
+  {
+    "deps": [
+      "gpr", 
+      "gpr_test_util", 
+      "grpc", 
+      "grpc_test_util"
+    ], 
+    "headers": [], 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "src": [
+      "test/core/support/percent_encode_fuzzer.c", 
+      "test/core/util/one_corpus_entry_fuzzer.c"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
   {
     "deps": [
       "gpr", 
@@ -5674,6 +5765,7 @@
       "src/core/lib/support/block_annotate.h", 
       "src/core/lib/support/env.h", 
       "src/core/lib/support/murmur_hash.h", 
+      "src/core/lib/support/percent_encoding.h", 
       "src/core/lib/support/stack_lockfree.h", 
       "src/core/lib/support/string.h", 
       "src/core/lib/support/string_windows.h", 
@@ -5738,6 +5830,8 @@
       "src/core/lib/support/log_windows.c", 
       "src/core/lib/support/murmur_hash.c", 
       "src/core/lib/support/murmur_hash.h", 
+      "src/core/lib/support/percent_encoding.c", 
+      "src/core/lib/support/percent_encoding.h", 
       "src/core/lib/support/slice.c", 
       "src/core/lib/support/slice_buffer.c", 
       "src/core/lib/support/stack_lockfree.c", 
diff --git a/tools/run_tests/tests.json b/tools/run_tests/tests.json
index c0f540791b4..b991cff3c99 100644
--- a/tools/run_tests/tests.json
+++ b/tools/run_tests/tests.json
@@ -697,6 +697,27 @@
       "windows"
     ]
   }, 
+  {
+    "args": [], 
+    "ci_platforms": [
+      "linux", 
+      "mac", 
+      "posix", 
+      "windows"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "flaky": false, 
+    "gtest": false, 
+    "language": "c", 
+    "name": "gpr_percent_encoding_test", 
+    "platforms": [
+      "linux", 
+      "mac", 
+      "posix", 
+      "windows"
+    ]
+  }, 
   {
     "args": [], 
     "ci_platforms": [
@@ -84414,6 +84435,576 @@
     ], 
     "uses_polling": false
   }, 
+  {
+    "args": [
+      "test/core/support/percent_decode_corpus/04cb8ccc553f9b2f5e52c421aff6d1c954d3dae6"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_decode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_decode_corpus/0dd8f3a63745b3a2d39791559b5c1b311447b537"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_decode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_decode_corpus/17eeaca784409adbe43365c32ac87915d736bba3"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_decode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_decode_corpus/56d08fea787c041395c6697ce26cfbc0decbe688"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_decode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_decode_corpus/678d981fdabb9f0d6640235cf1719dd1e1e66ae9"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_decode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_decode_corpus/68751961609ec010565de0aa87521dcbf0722c5d"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_decode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_decode_corpus/7875c06c6f03c9aa2f8e9c59f8d8957c8a32e759"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_decode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_decode_corpus/875e1022169c9e4c541a9ad894e69e989df22ba1"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_decode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_decode_corpus/9d316c4675f40ddccaf8f1cc7aea94170b1e4223"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_decode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_decode_corpus/b471f94aa4facf502e622e4a248f1ba4063ae681"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_decode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_decode_corpus/bf52ece030f16136d46e0dc97f58d60a0d8a1f0b"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_decode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_decode_corpus/d5b2a7177339ba2b7ce2f60e5f4459bef1e72758"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_decode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_decode_corpus/de867b64c54a7ed773dc611fc5cd2f17c5433113"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_decode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_decode_corpus/xyz"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_decode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/0d3ee7fa54e6c66103965fd4409b044ba7db6c3f"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/2e7ccf75e27b9501e3b28cf1c50ed0c45ab7c226"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/55bb859f3942c462b03b7cbcf22ab4a0ac9705cf"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/56070cecd54c845b6d4334953b17b712eb000d93"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/61f50e891bf7ff5eb7a7af206f1e25d77f8756e7"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/6e0c60cefc704c7940e475a87dd9ae423061cb5a"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/7271ebcc6d22a0f186f7bc3c1973a7ed1bec8d8e"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/74c83ece3e2920a67593a9be9c82468f16cbb969"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/98e004fd2a9f141a7a019720820080e12d637c06"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/ba2c1e98227aa21ea3bb2ca4d0e504119717da8b"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/c16b9fd45370d4afb5d3ebd307a6e263c25ffd45"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/d58c3cd4eab9b6d2343abfa1c25c90a383fe0ec3"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/e2619218ede30d2b7b8ecd601a9f0ae754b728b4"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/f93b3653e453f0e3eea3198001be6ce46e64bd21"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/fd41d029c7682ad3d1c40a9fd017a4c85b673a54"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
+  {
+    "args": [
+      "test/core/support/percent_encode_corpus/xyz"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 0.1, 
+    "exclude_configs": [
+      "tsan"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "percent_encode_fuzzer_one_entry", 
+    "platforms": [
+      "linux"
+    ], 
+    "uses_polling": false
+  }, 
   {
     "args": [
       "test/core/end2end/fuzzers/server_fuzzer_corpus/01c008fa.bin"
diff --git a/vsprojects/buildtests_c.sln b/vsprojects/buildtests_c.sln
index c28f3ba39c3..8f3546f7bec 100644
--- a/vsprojects/buildtests_c.sln
+++ b/vsprojects/buildtests_c.sln
@@ -300,6 +300,11 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "gen_legal_metadata_characte
         	lib = "False"
 	EndProjectSection
 EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "gen_percent_encoding_tables", "vcxproj\.\gen_percent_encoding_tables\gen_percent_encoding_tables.vcxproj", "{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}"
+	ProjectSection(myProperties) = preProject
+        	lib = "False"
+	EndProjectSection
+EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "gpr", "vcxproj\.\gpr\gpr.vcxproj", "{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}"
 	ProjectSection(myProperties) = preProject
         	lib = "True"
@@ -377,6 +382,15 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "gpr_log_test", "vcxproj\tes
 		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792} = {B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}
 	EndProjectSection
 EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "gpr_percent_encoding_test", "vcxproj\test\gpr_percent_encoding_test\gpr_percent_encoding_test.vcxproj", "{8313AE17-FCFA-8110-95C7-7AF2F814D188}"
+	ProjectSection(myProperties) = preProject
+        	lib = "False"
+	EndProjectSection
+	ProjectSection(ProjectDependencies) = postProject
+		{EAB0A629-17A9-44DB-B5FF-E91A721FE037} = {EAB0A629-17A9-44DB-B5FF-E91A721FE037}
+		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792} = {B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}
+	EndProjectSection
+EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "gpr_slice_buffer_test", "vcxproj\test\gpr_slice_buffer_test\gpr_slice_buffer_test.vcxproj", "{E679773D-DE89-AEBB-9787-59019989B825}"
 	ProjectSection(myProperties) = preProject
         	lib = "False"
@@ -1898,6 +1912,22 @@ Global
 		{A635DE99-B131-CA00-2D3B-8691D60B76C2}.Release-DLL|Win32.Build.0 = Release|Win32
 		{A635DE99-B131-CA00-2D3B-8691D60B76C2}.Release-DLL|x64.ActiveCfg = Release|x64
 		{A635DE99-B131-CA00-2D3B-8691D60B76C2}.Release-DLL|x64.Build.0 = Release|x64
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug|Win32.ActiveCfg = Debug|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug|x64.ActiveCfg = Debug|x64
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release|Win32.ActiveCfg = Release|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release|x64.ActiveCfg = Release|x64
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug|Win32.Build.0 = Debug|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug|x64.Build.0 = Debug|x64
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release|Win32.Build.0 = Release|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release|x64.Build.0 = Release|x64
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug-DLL|Win32.ActiveCfg = Debug|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug-DLL|Win32.Build.0 = Debug|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug-DLL|x64.ActiveCfg = Debug|x64
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug-DLL|x64.Build.0 = Debug|x64
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release-DLL|Win32.ActiveCfg = Release|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release-DLL|Win32.Build.0 = Release|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release-DLL|x64.ActiveCfg = Release|x64
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release-DLL|x64.Build.0 = Release|x64
 		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}.Debug|Win32.ActiveCfg = Debug|Win32
 		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}.Debug|x64.ActiveCfg = Debug|x64
 		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}.Release|Win32.ActiveCfg = Release|Win32
@@ -2042,6 +2072,22 @@ Global
 		{38797EE3-62CC-3CBF-18D5-009ED6DD0BEC}.Release-DLL|Win32.Build.0 = Release|Win32
 		{38797EE3-62CC-3CBF-18D5-009ED6DD0BEC}.Release-DLL|x64.ActiveCfg = Release|x64
 		{38797EE3-62CC-3CBF-18D5-009ED6DD0BEC}.Release-DLL|x64.Build.0 = Release|x64
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Debug|Win32.ActiveCfg = Debug|Win32
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Debug|x64.ActiveCfg = Debug|x64
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Release|Win32.ActiveCfg = Release|Win32
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Release|x64.ActiveCfg = Release|x64
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Debug|Win32.Build.0 = Debug|Win32
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Debug|x64.Build.0 = Debug|x64
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Release|Win32.Build.0 = Release|Win32
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Release|x64.Build.0 = Release|x64
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Debug-DLL|Win32.ActiveCfg = Debug|Win32
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Debug-DLL|Win32.Build.0 = Debug|Win32
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Debug-DLL|x64.ActiveCfg = Debug|x64
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Debug-DLL|x64.Build.0 = Debug|x64
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Release-DLL|Win32.ActiveCfg = Release|Win32
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Release-DLL|Win32.Build.0 = Release|Win32
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Release-DLL|x64.ActiveCfg = Release|x64
+		{8313AE17-FCFA-8110-95C7-7AF2F814D188}.Release-DLL|x64.Build.0 = Release|x64
 		{E679773D-DE89-AEBB-9787-59019989B825}.Debug|Win32.ActiveCfg = Debug|Win32
 		{E679773D-DE89-AEBB-9787-59019989B825}.Debug|x64.ActiveCfg = Debug|x64
 		{E679773D-DE89-AEBB-9787-59019989B825}.Release|Win32.ActiveCfg = Release|Win32
diff --git a/vsprojects/grpc.sln b/vsprojects/grpc.sln
index 8fccc646e5c..c75c65f9e18 100644
--- a/vsprojects/grpc.sln
+++ b/vsprojects/grpc.sln
@@ -22,6 +22,11 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "gen_legal_metadata_characte
         	lib = "False"
 	EndProjectSection
 EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "gen_percent_encoding_tables", "vcxproj\.\gen_percent_encoding_tables\gen_percent_encoding_tables.vcxproj", "{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}"
+	ProjectSection(myProperties) = preProject
+        	lib = "False"
+	EndProjectSection
+EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "gpr", "vcxproj\.\gpr\gpr.vcxproj", "{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}"
 	ProjectSection(myProperties) = preProject
         	lib = "True"
@@ -222,6 +227,22 @@ Global
 		{A635DE99-B131-CA00-2D3B-8691D60B76C2}.Release-DLL|Win32.Build.0 = Release|Win32
 		{A635DE99-B131-CA00-2D3B-8691D60B76C2}.Release-DLL|x64.ActiveCfg = Release|x64
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+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug|Win32.ActiveCfg = Debug|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug|x64.ActiveCfg = Debug|x64
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release|Win32.ActiveCfg = Release|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release|x64.ActiveCfg = Release|x64
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug|Win32.Build.0 = Debug|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug|x64.Build.0 = Debug|x64
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release|Win32.Build.0 = Release|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release|x64.Build.0 = Release|x64
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug-DLL|Win32.ActiveCfg = Debug|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug-DLL|Win32.Build.0 = Debug|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug-DLL|x64.ActiveCfg = Debug|x64
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Debug-DLL|x64.Build.0 = Debug|x64
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release-DLL|Win32.ActiveCfg = Release|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release-DLL|Win32.Build.0 = Release|Win32
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release-DLL|x64.ActiveCfg = Release|x64
+		{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}.Release-DLL|x64.Build.0 = Release|x64
 		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}.Debug|Win32.ActiveCfg = Debug|Win32
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 		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}.Release|Win32.ActiveCfg = Release|Win32
diff --git a/vsprojects/vcxproj/gen_percent_encoding_tables/gen_percent_encoding_tables.vcxproj b/vsprojects/vcxproj/gen_percent_encoding_tables/gen_percent_encoding_tables.vcxproj
new file mode 100644
index 00000000000..446b4129d2c
--- /dev/null
+++ b/vsprojects/vcxproj/gen_percent_encoding_tables/gen_percent_encoding_tables.vcxproj
@@ -0,0 +1,162 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="12.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|x64">
+      <Configuration>Debug</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|x64">
+      <Configuration>Release</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{95D6E277-5ED9-EBDB-3DB8-19C610D2C6F5}</ProjectGuid>
+    <IgnoreWarnIntDirInTempDetected>true</IgnoreWarnIntDirInTempDetected>
+    <IntDir>$(SolutionDir)IntDir\$(MSBuildProjectName)\</IntDir>
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+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(VisualStudioVersion)' == '10.0'" Label="Configuration">
+    <PlatformToolset>v100</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(VisualStudioVersion)' == '11.0'" Label="Configuration">
+    <PlatformToolset>v110</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(VisualStudioVersion)' == '12.0'" Label="Configuration">
+    <PlatformToolset>v120</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(VisualStudioVersion)' == '14.0'" Label="Configuration">
+    <PlatformToolset>v140</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)'=='Debug'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)'=='Release'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+    <Import Project="$(SolutionDir)\..\vsprojects\global.props" />
+    <Import Project="$(SolutionDir)\..\vsprojects\winsock.props" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup Condition="'$(Configuration)'=='Debug'">
+    <TargetName>gen_percent_encoding_tables</TargetName>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)'=='Release'">
+    <TargetName>gen_percent_encoding_tables</TargetName>
+  </PropertyGroup>
+    <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <ClCompile>
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+      <WarningLevel>Level3</WarningLevel>
+      <Optimization>Disabled</Optimization>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_LIB;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <SDLCheck>true</SDLCheck>
+      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+      <TreatWarningAsError>true</TreatWarningAsError>
+      <DebugInformationFormat Condition="$(Jenkins)">None</DebugInformationFormat>
+      <MinimalRebuild Condition="$(Jenkins)">false</MinimalRebuild>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation Condition="!$(Jenkins)">true</GenerateDebugInformation>
+      <GenerateDebugInformation Condition="$(Jenkins)">false</GenerateDebugInformation>
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+    <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+    <ClCompile>
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+      <WarningLevel>Level3</WarningLevel>
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+      <PreprocessorDefinitions>WIN32;_DEBUG;_LIB;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <SDLCheck>true</SDLCheck>
+      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+      <TreatWarningAsError>true</TreatWarningAsError>
+      <DebugInformationFormat Condition="$(Jenkins)">None</DebugInformationFormat>
+      <MinimalRebuild Condition="$(Jenkins)">false</MinimalRebuild>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation Condition="!$(Jenkins)">true</GenerateDebugInformation>
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+
+    <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <ClCompile>
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+      <WarningLevel>Level3</WarningLevel>
+      <Optimization>MaxSpeed</Optimization>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_LIB;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <SDLCheck>true</SDLCheck>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+      <TreatWarningAsError>true</TreatWarningAsError>
+      <DebugInformationFormat Condition="$(Jenkins)">None</DebugInformationFormat>
+      <MinimalRebuild Condition="$(Jenkins)">false</MinimalRebuild>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation Condition="!$(Jenkins)">true</GenerateDebugInformation>
+      <GenerateDebugInformation Condition="$(Jenkins)">false</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
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+    <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <ClCompile>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <WarningLevel>Level3</WarningLevel>
+      <Optimization>MaxSpeed</Optimization>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_LIB;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <SDLCheck>true</SDLCheck>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+      <TreatWarningAsError>true</TreatWarningAsError>
+      <DebugInformationFormat Condition="$(Jenkins)">None</DebugInformationFormat>
+      <MinimalRebuild Condition="$(Jenkins)">false</MinimalRebuild>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation Condition="!$(Jenkins)">true</GenerateDebugInformation>
+      <GenerateDebugInformation Condition="$(Jenkins)">false</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+    </Link>
+  </ItemDefinitionGroup>
+
+  <ItemGroup>
+    <ClCompile Include="$(SolutionDir)\..\tools\codegen\core\gen_percent_encoding_tables.c">
+    </ClCompile>
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+  <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
+    <PropertyGroup>
+      <ErrorText>This project references NuGet package(s) that are missing on this computer. Enable NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
+    </PropertyGroup>
+  </Target>
+</Project>
+
diff --git a/vsprojects/vcxproj/gen_percent_encoding_tables/gen_percent_encoding_tables.vcxproj.filters b/vsprojects/vcxproj/gen_percent_encoding_tables/gen_percent_encoding_tables.vcxproj.filters
new file mode 100644
index 00000000000..a787887c886
--- /dev/null
+++ b/vsprojects/vcxproj/gen_percent_encoding_tables/gen_percent_encoding_tables.vcxproj.filters
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup>
+    <ClCompile Include="$(SolutionDir)\..\tools\codegen\core\gen_percent_encoding_tables.c">
+      <Filter>tools\codegen\core</Filter>
+    </ClCompile>
+  </ItemGroup>
+
+  <ItemGroup>
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+    <Filter Include="tools\codegen">
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+    <Filter Include="tools\codegen\core">
+      <UniqueIdentifier>{194d6b8d-bf65-b581-90a4-13447dbfa951}</UniqueIdentifier>
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+</Project>
+
diff --git a/vsprojects/vcxproj/gpr/gpr.vcxproj b/vsprojects/vcxproj/gpr/gpr.vcxproj
index db8594e7458..519b5d92502 100644
--- a/vsprojects/vcxproj/gpr/gpr.vcxproj
+++ b/vsprojects/vcxproj/gpr/gpr.vcxproj
@@ -196,6 +196,7 @@
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     <ClInclude Include="$(SolutionDir)\..\src\core\lib\support\env.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\support\murmur_hash.h" />
+    <ClInclude Include="$(SolutionDir)\..\src\core\lib\support\percent_encoding.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\support\stack_lockfree.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\support\string.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\support\string_windows.h" />
@@ -246,6 +247,8 @@
     </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\support\murmur_hash.c">
     </ClCompile>
+    <ClCompile Include="$(SolutionDir)\..\src\core\lib\support\percent_encoding.c">
+    </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\support\slice.c">
     </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\support\slice_buffer.c">
diff --git a/vsprojects/vcxproj/gpr/gpr.vcxproj.filters b/vsprojects/vcxproj/gpr/gpr.vcxproj.filters
index 9bab373513e..9eac1ec5195 100644
--- a/vsprojects/vcxproj/gpr/gpr.vcxproj.filters
+++ b/vsprojects/vcxproj/gpr/gpr.vcxproj.filters
@@ -64,6 +64,9 @@
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\support\murmur_hash.c">
       <Filter>src\core\lib\support</Filter>
     </ClCompile>
+    <ClCompile Include="$(SolutionDir)\..\src\core\lib\support\percent_encoding.c">
+      <Filter>src\core\lib\support</Filter>
+    </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\support\slice.c">
       <Filter>src\core\lib\support</Filter>
     </ClCompile>
@@ -281,6 +284,9 @@
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\support\murmur_hash.h">
       <Filter>src\core\lib\support</Filter>
     </ClInclude>
+    <ClInclude Include="$(SolutionDir)\..\src\core\lib\support\percent_encoding.h">
+      <Filter>src\core\lib\support</Filter>
+    </ClInclude>
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\support\stack_lockfree.h">
       <Filter>src\core\lib\support</Filter>
     </ClInclude>
diff --git a/vsprojects/vcxproj/test/gpr_percent_encoding_test/gpr_percent_encoding_test.vcxproj b/vsprojects/vcxproj/test/gpr_percent_encoding_test/gpr_percent_encoding_test.vcxproj
new file mode 100644
index 00000000000..1a943e4e8ea
--- /dev/null
+++ b/vsprojects/vcxproj/test/gpr_percent_encoding_test/gpr_percent_encoding_test.vcxproj
@@ -0,0 +1,193 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="12.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.1.0.204.1\build\native\grpc.dependencies.openssl.props" Condition="Exists('$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.1.0.204.1\build\native\1.0.204.1.props')" />
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug|Win32">
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+    <ProjectGuid>{8313AE17-FCFA-8110-95C7-7AF2F814D188}</ProjectGuid>
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+    <PlatformToolset>v120</PlatformToolset>
+  </PropertyGroup>
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+    <PlatformToolset>v140</PlatformToolset>
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+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)'=='Release'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
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+    <Import Project="$(SolutionDir)\..\vsprojects\openssl.props" />
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+  <Import Project="$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.zlib.1.2.8.10\build\native\grpc.dependencies.zlib.targets" Condition="Exists('$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.zlib.1.2.8.10\build\native\grpc.dependencies\grpc.dependencies.zlib.targets')" />
+  <Import Project="$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.redist.1.0.204.1\build\native\grpc.dependencies.openssl.redist.targets" Condition="Exists('$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.redist.1.0.204.1\build\native\grpc.dependencies\grpc.dependencies.openssl.targets')" />
+  <Import Project="$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.1.0.204.1\build\native\grpc.dependencies.openssl.targets" Condition="Exists('$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.1.0.204.1\build\native\grpc.dependencies\grpc.dependencies.openssl.targets')" />
+  </ImportGroup>
+  <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
+    <PropertyGroup>
+      <ErrorText>This project references NuGet package(s) that are missing on this computer. Enable NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
+    </PropertyGroup>
+    <Error Condition="!Exists('$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.zlib.redist.1.2.8.10\build\native\grpc.dependencies.zlib.redist.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.zlib.redist.1.2.8.10\build\native\grpc.dependencies.zlib.redist.targets')" />
+    <Error Condition="!Exists('$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.zlib.1.2.8.10\build\native\grpc.dependencies.zlib.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.zlib.1.2.8.10\build\native\grpc.dependencies.zlib.targets')" />
+    <Error Condition="!Exists('$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.redist.1.0.204.1\build\native\grpc.dependencies.openssl.redist.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.redist.1.0.204.1\build\native\grpc.dependencies.openssl.redist.targets')" />
+    <Error Condition="!Exists('$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.1.0.204.1\build\native\grpc.dependencies.openssl.props')" Text="$([System.String]::Format('$(ErrorText)', '$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.1.0.204.1\build\native\grpc.dependencies.openssl.props')" />
+    <Error Condition="!Exists('$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.1.0.204.1\build\native\grpc.dependencies.openssl.targets')" Text="$([System.String]::Format('$(ErrorText)', '$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.1.0.204.1\build\native\grpc.dependencies.openssl.targets')" />
+  </Target>
+</Project>
+
diff --git a/vsprojects/vcxproj/test/gpr_percent_encoding_test/gpr_percent_encoding_test.vcxproj.filters b/vsprojects/vcxproj/test/gpr_percent_encoding_test/gpr_percent_encoding_test.vcxproj.filters
new file mode 100644
index 00000000000..e25b1ad6566
--- /dev/null
+++ b/vsprojects/vcxproj/test/gpr_percent_encoding_test/gpr_percent_encoding_test.vcxproj.filters
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup>
+    <ClCompile Include="$(SolutionDir)\..\test\core\support\percent_encoding_test.c">
+      <Filter>test\core\support</Filter>
+    </ClCompile>
+  </ItemGroup>
+
+  <ItemGroup>
+    <Filter Include="test">
+      <UniqueIdentifier>{c2ea1ce7-c916-11e7-6477-92a18d988d54}</UniqueIdentifier>
+    </Filter>
+    <Filter Include="test\core">
+      <UniqueIdentifier>{14fa1f36-5dea-ee3f-d3fa-a137176b235f}</UniqueIdentifier>
+    </Filter>
+    <Filter Include="test\core\support">
+      <UniqueIdentifier>{e245dffe-593f-f63e-8dc8-3c9de4d00697}</UniqueIdentifier>
+    </Filter>
+  </ItemGroup>
+</Project>
+