diff --git a/src/core/lib/channel/http_client_filter.c b/src/core/lib/channel/http_client_filter.c
index d26455e1301..b69ab997042 100644
--- a/src/core/lib/channel/http_client_filter.c
+++ b/src/core/lib/channel/http_client_filter.c
@@ -294,32 +294,32 @@ static grpc_error *hc_mutate_op(grpc_exec_ctx *exec_ctx,
       if (calld->send_message_blocked == false) {
         /* when all the send_message data is available, then modify the path
          * MDELEM by appending base64 encoded query to the path */
-        static const int k_url_safe = 1;
-        static const int k_multi_line = 0;
-        static const char *k_query_separator = "?";
+        const int k_url_safe = 1;
+        const int k_multi_line = 0;
+        const char *k_query_separator = "?";
+        const size_t k_query_separator_len = GPR_ARRAY_SIZE(k_query_separator);
 
         grpc_slice path_slice =
             GRPC_MDVALUE(op->send_initial_metadata->idx.named.path->md);
         /* sum up individual component's lengths and allocate enough memory to
          * hold combined path+query */
         size_t estimated_len = GRPC_SLICE_LENGTH(path_slice);
-        estimated_len += strlen(k_query_separator);
+        estimated_len += k_query_separator_len;
         estimated_len += grpc_base64_estimate_encoded_size(
             op->send_message->length, k_url_safe, k_multi_line);
         estimated_len += 1; /* for the trailing 0 */
         grpc_slice path_with_query_slice = grpc_slice_malloc(estimated_len);
 
         /* memcopy individual pieces into this slice */
-        char *write_ptr = (char *)GRPC_SLICE_START_PTR(path_with_query_slice);
-
-        char *original_path = (char *)GRPC_SLICE_START_PTR(path_slice);
+        uint8_t *write_ptr = (uint8_t *)GRPC_SLICE_START_PTR(path_with_query_slice);
+        uint8_t *original_path = (uint8_t *)GRPC_SLICE_START_PTR(path_slice);
         memcpy(write_ptr, original_path, GRPC_SLICE_LENGTH(path_slice));
-        write_ptr += (int)GRPC_SLICE_LENGTH(path_slice);
+        write_ptr += GRPC_SLICE_LENGTH(path_slice);
 
-        memcpy(write_ptr, k_query_separator, strlen(k_query_separator));
-        write_ptr += strlen(k_query_separator);
+        memcpy(write_ptr, k_query_separator, k_query_separator_len);
+        write_ptr += k_query_separator_len;
 
-        grpc_base64_encode_core(write_ptr, calld->payload_bytes,
+        grpc_base64_encode_core((char *)write_ptr, calld->payload_bytes,
                                 op->send_message->length, k_url_safe,
                                 k_multi_line);
 
@@ -327,9 +327,9 @@ static grpc_error *hc_mutate_op(grpc_exec_ctx *exec_ctx,
          */
         char *t = (char *)GRPC_SLICE_START_PTR(path_with_query_slice);
         size_t path_length = strlen(t) + 1;
-        *(t + path_length) = 0;
+        *(t + path_length) = '\0';
         path_with_query_slice =
-            grpc_slice_sub(path_with_query_slice, 0, path_length);
+            grpc_slice_sub_no_ref(path_with_query_slice, 0, path_length);
 
         /* substitute previous path with the new path+query */
         grpc_mdelem mdelem_path_and_query = grpc_mdelem_from_slices(
diff --git a/src/core/lib/channel/http_server_filter.c b/src/core/lib/channel/http_server_filter.c
index 31149aa1169..4ca4602cba0 100644
--- a/src/core/lib/channel/http_server_filter.c
+++ b/src/core/lib/channel/http_server_filter.c
@@ -200,9 +200,9 @@ static grpc_error *server_filter_incoming_metadata(grpc_exec_ctx *exec_ctx,
   } else if (*calld->recv_cacheable_request == true) {
     /* We have a cacheable request made with GET verb. The path contains the
      * query parameter which is base64 encoded request payload. */
-    static const char *k_query_separator = "?";
+    const char *k_query_separator = "?";
     grpc_slice path_slice = GRPC_MDVALUE(b->idx.named.path->md);
-    char *path_ptr = (char *)GRPC_SLICE_START_PTR(path_slice);
+    uint8_t *path_ptr = (uint8_t *)GRPC_SLICE_START_PTR(path_slice);
     size_t path_length = GRPC_SLICE_LENGTH(path_slice);
     /* offset of the character '?' */
     size_t offset = 0;
@@ -220,7 +220,7 @@ static grpc_error *server_filter_incoming_metadata(grpc_exec_ctx *exec_ctx,
                                    mdelem_path_without_query);
 
     /* decode payload from query and add to the slice buffer to be returned */
-    static const int k_url_safe = 1;
+    const int k_url_safe = 1;
     grpc_slice_buffer_add(
         &calld->read_slice_buffer,
         grpc_base64_decode(exec_ctx,