diff --git a/conformance/conformance.proto b/conformance/conformance.proto
index a3bbc1a488..c4aed80ad0 100644
--- a/conformance/conformance.proto
+++ b/conformance/conformance.proto
@@ -35,8 +35,8 @@ enum WireFormat {
   UNSPECIFIED = 0;
   PROTOBUF = 1;
   JSON = 2;
+  JSPB = 3;  // Only used inside Google. Opensource testees just skip it.
   TEXT_FORMAT = 4;
-  reserved 3;
 }
 
 enum TestCategory {
@@ -49,10 +49,12 @@ enum TestCategory {
   // https://developers.google.com/protocol-buffers/docs/proto3#json_options
   // for more detail.
   JSON_IGNORE_UNKNOWN_PARSING_TEST = 3;
+  // Test jspb wire format. Only used inside Google. Opensource testees just
+  // skip it.
+  JSPB_TEST = 4;
   // Test text format. For cpp, java and python, testees can already deal with
   // this type. Testees of other languages can simply skip it.
   TEXT_FORMAT_TEST = 5;
-  reserved 4;
 }
 
 // The conformance runner will request a list of failures as the first request.
@@ -74,6 +76,8 @@ message ConformanceRequest {
   oneof payload {
     bytes protobuf_payload = 1;
     string json_payload = 2;
+    // Only used inside Google.  Opensource testees just skip it.
+    string jspb_payload = 7;
     string text_payload = 8;
   }
 
@@ -90,11 +94,12 @@ message ConformanceRequest {
   // TestCategory for more information.
   TestCategory test_category = 5;
 
+  // Specify details for how to encode jspb.
+  JspbEncodingConfig jspb_encoding_options = 6;
+
   // This can be used in json and text format. If true, testee should print
   // unknown fields instead of ignore. This feature is optional.
   bool print_unknown_fields = 9;
-
-  reserved 6, 7;
 }
 
 // Represents a single test case's output.
@@ -134,10 +139,19 @@ message ConformanceResponse {
     // wasn't supported, like JSON input/output.
     string skipped = 5;
 
+    // If the input was successfully parsed and the requested output was JSPB,
+    // serialize to JSPB and set it in this field. JSPB is only used inside
+    // Google. Opensource testees can just skip it.
+    string jspb_payload = 7;
+
     // If the input was successfully parsed and the requested output was
     // TEXT_FORMAT, serialize to TEXT_FORMAT and set it in this field.
     string text_payload = 8;
   }
+}
 
-  reserved 7;
+// Encoding options for jspb format.
+message JspbEncodingConfig {
+  // Encode the value field of Any as jspb array if true, otherwise binary.
+  bool use_jspb_array_any_format = 1;
 }
diff --git a/conformance/conformance_objc.m b/conformance/conformance_objc.m
index 17b1f4de2f..8a37b72bec 100644
--- a/conformance/conformance_objc.m
+++ b/conformance/conformance_objc.m
@@ -78,6 +78,11 @@ static ConformanceResponse *DoTest(ConformanceRequest *request) {
       response.skipped = @"ObjC doesn't support parsing JSON";
       break;
 
+    case ConformanceRequest_Payload_OneOfCase_JspbPayload:
+      response.skipped = @"ConformanceRequest had a jspb_payload ConformanceRequest.payload;"
+                          " those aren't supposed to happen with opensource.";
+      break;
+
     case ConformanceRequest_Payload_OneOfCase_TextPayload:
       response.skipped = @"ObjC doesn't support parsing TextFormat";
       break;
@@ -103,6 +108,12 @@ static ConformanceResponse *DoTest(ConformanceRequest *request) {
         response.skipped = @"ObjC doesn't support generating JSON";
         break;
 
+      case ConformanceWireFormat_Jspb:
+        response.skipped =
+            @"ConformanceRequest had a requested_output_format of JSPB WireFormat; that"
+             " isn't supposed to happen with opensource.";
+        break;
+
       case ConformanceWireFormat_TextFormat:
         // ObjC only has partial objc generation, so don't attempt any tests that need
         // support.
diff --git a/conformance/conformance_test.cc b/conformance/conformance_test.cc
index 9fb32d87ce..ef049c8a53 100644
--- a/conformance/conformance_test.cc
+++ b/conformance/conformance_test.cc
@@ -115,6 +115,11 @@ ConformanceTestSuite::ConformanceRequestSetting::ConformanceRequestSetting(
       break;
     }
 
+    case conformance::JSPB: {
+      request_.set_jspb_payload(input);
+      break;
+    }
+
     case conformance::TEXT_FORMAT: {
       request_.set_text_payload(input);
       break;
@@ -225,6 +230,9 @@ ConformanceRequest ConformanceTestSuite::TruncateRequest(
     case ConformanceRequest::kTextPayload:
       TruncateDebugPayload(debug_request.mutable_text_payload());
       break;
+    case ConformanceRequest::kJspbPayload:
+      TruncateDebugPayload(debug_request.mutable_jspb_payload());
+      break;
     default:
       // Do nothing.
       break;
@@ -245,6 +253,9 @@ ConformanceResponse ConformanceTestSuite::TruncateResponse(
     case ConformanceResponse::kTextPayload:
       TruncateDebugPayload(debug_response.mutable_text_payload());
       break;
+    case ConformanceResponse::kJspbPayload:
+      TruncateDebugPayload(debug_response.mutable_jspb_payload());
+      break;
     default:
       // Do nothing.
       break;
@@ -418,6 +429,8 @@ std::string ConformanceTestSuite::WireFormatToString(WireFormat wire_format) {
       return "PROTOBUF";
     case conformance::JSON:
       return "JSON";
+    case conformance::JSPB:
+      return "JSPB";
     case conformance::TEXT_FORMAT:
       return "TEXT_FORMAT";
     case conformance::UNSPECIFIED: