diff --git a/grpcstub_test.go b/grpcstub_test.go
index 740308b..64ebe8e 100644
--- a/grpcstub_test.go
+++ b/grpcstub_test.go
@@ -682,6 +682,27 @@ func TestResponseAny(t *testing.T) {
 	}
 }
 
+func TestResponseAnyFields(t *testing.T) {
+	ctx := context.Background()
+	ts := NewServer(t, "testdata/hello.proto")
+	t.Cleanup(func() {
+		ts.Close()
+	})
+	ts.Service("hello.GrpcTestService").Method("HelloFields").ResponseString(`{"field_bytes": "aGVsbG8="}`) // Base64 encoding to pass bytes type
+
+	client := hello.NewGrpcTestServiceClient(ts.Conn())
+	res, err := client.HelloFields(ctx, &hello.HelloFieldsRequest{
+		FieldBytes: []byte("hello"),
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	got := res.FieldBytes
+	if want := "hello"; string(got) != want {
+		t.Errorf("got %v\nwant %v", got, want)
+	}
+}
+
 func TestBufProtoRegistry(t *testing.T) {
 	t.Run("Use buf.lock", func(t *testing.T) {
 		ts := NewServer(t, "testdata/bsr/protobuf/pinger/pinger.proto", BufLock("testdata/bsr/protobuf/buf.lock"))
diff --git a/testdata/hello.proto b/testdata/hello.proto
index b7c2022..2c02c94 100644
--- a/testdata/hello.proto
+++ b/testdata/hello.proto
@@ -8,6 +8,7 @@ package hello;
 
 service GrpcTestService {
 	rpc Hello (HelloRequest) returns (HelloResponse);
+  rpc HelloFields (HelloFieldsRequest) returns (HelloFieldsResponse);
 }
 
 message HelloRequest {
@@ -29,3 +30,11 @@ message HelloResponse {
 
   google.protobuf.Timestamp create_time = 5;
 }
+
+message HelloFieldsRequest {
+  bytes field_bytes = 1;
+}
+
+message HelloFieldsResponse {
+  bytes field_bytes = 1;
+}
diff --git a/testdata/hello/hello.pb.go b/testdata/hello/hello.pb.go
index 1bff53d..19f126a 100644
--- a/testdata/hello/hello.pb.go
+++ b/testdata/hello/hello.pb.go
@@ -1,7 +1,7 @@
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
-// 	protoc-gen-go v1.30.0
-// 	protoc        v3.21.12
+// 	protoc-gen-go v1.33.0
+// 	protoc        v4.25.3
 // source: hello.proto
 
 package hello
@@ -163,6 +163,100 @@ func (x *HelloResponse) GetCreateTime() *timestamppb.Timestamp {
 	return nil
 }
 
+type HelloFieldsRequest struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	FieldBytes []byte `protobuf:"bytes,1,opt,name=field_bytes,json=fieldBytes,proto3" json:"field_bytes,omitempty"`
+}
+
+func (x *HelloFieldsRequest) Reset() {
+	*x = HelloFieldsRequest{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_hello_proto_msgTypes[2]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *HelloFieldsRequest) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*HelloFieldsRequest) ProtoMessage() {}
+
+func (x *HelloFieldsRequest) ProtoReflect() protoreflect.Message {
+	mi := &file_hello_proto_msgTypes[2]
+	if protoimpl.UnsafeEnabled && x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use HelloFieldsRequest.ProtoReflect.Descriptor instead.
+func (*HelloFieldsRequest) Descriptor() ([]byte, []int) {
+	return file_hello_proto_rawDescGZIP(), []int{2}
+}
+
+func (x *HelloFieldsRequest) GetFieldBytes() []byte {
+	if x != nil {
+		return x.FieldBytes
+	}
+	return nil
+}
+
+type HelloFieldsResponse struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	FieldBytes []byte `protobuf:"bytes,1,opt,name=field_bytes,json=fieldBytes,proto3" json:"field_bytes,omitempty"`
+}
+
+func (x *HelloFieldsResponse) Reset() {
+	*x = HelloFieldsResponse{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_hello_proto_msgTypes[3]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *HelloFieldsResponse) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*HelloFieldsResponse) ProtoMessage() {}
+
+func (x *HelloFieldsResponse) ProtoReflect() protoreflect.Message {
+	mi := &file_hello_proto_msgTypes[3]
+	if protoimpl.UnsafeEnabled && x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use HelloFieldsResponse.ProtoReflect.Descriptor instead.
+func (*HelloFieldsResponse) Descriptor() ([]byte, []int) {
+	return file_hello_proto_rawDescGZIP(), []int{3}
+}
+
+func (x *HelloFieldsResponse) GetFieldBytes() []byte {
+	if x != nil {
+		return x.FieldBytes
+	}
+	return nil
+}
+
 var File_hello_proto protoreflect.FileDescriptor
 
 var file_hello_proto_rawDesc = []byte{
@@ -188,12 +282,24 @@ var file_hello_proto_rawDesc = []byte{
 	0x32, 0x1a, 0x2e, 0x67, 0x6f, 0x6f, 0x67, 0x6c, 0x65, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62,
 	0x75, 0x66, 0x2e, 0x54, 0x69, 0x6d, 0x65, 0x73, 0x74, 0x61, 0x6d, 0x70, 0x52, 0x0a, 0x63, 0x72,
 	0x65, 0x61, 0x74, 0x65, 0x54, 0x69, 0x6d, 0x65, 0x42, 0x08, 0x0a, 0x06, 0x5f, 0x77, 0x6f, 0x72,
-	0x6c, 0x64, 0x32, 0x45, 0x0a, 0x0f, 0x47, 0x72, 0x70, 0x63, 0x54, 0x65, 0x73, 0x74, 0x53, 0x65,
+	0x6c, 0x64, 0x22, 0x35, 0x0a, 0x12, 0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x46, 0x69, 0x65, 0x6c, 0x64,
+	0x73, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x12, 0x1f, 0x0a, 0x0b, 0x66, 0x69, 0x65, 0x6c,
+	0x64, 0x5f, 0x62, 0x79, 0x74, 0x65, 0x73, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0c, 0x52, 0x0a, 0x66,
+	0x69, 0x65, 0x6c, 0x64, 0x42, 0x79, 0x74, 0x65, 0x73, 0x22, 0x36, 0x0a, 0x13, 0x48, 0x65, 0x6c,
+	0x6c, 0x6f, 0x46, 0x69, 0x65, 0x6c, 0x64, 0x73, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65,
+	0x12, 0x1f, 0x0a, 0x0b, 0x66, 0x69, 0x65, 0x6c, 0x64, 0x5f, 0x62, 0x79, 0x74, 0x65, 0x73, 0x18,
+	0x01, 0x20, 0x01, 0x28, 0x0c, 0x52, 0x0a, 0x66, 0x69, 0x65, 0x6c, 0x64, 0x42, 0x79, 0x74, 0x65,
+	0x73, 0x32, 0x8b, 0x01, 0x0a, 0x0f, 0x47, 0x72, 0x70, 0x63, 0x54, 0x65, 0x73, 0x74, 0x53, 0x65,
 	0x72, 0x76, 0x69, 0x63, 0x65, 0x12, 0x32, 0x0a, 0x05, 0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x12, 0x13,
 	0x2e, 0x68, 0x65, 0x6c, 0x6c, 0x6f, 0x2e, 0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x52, 0x65, 0x71, 0x75,
 	0x65, 0x73, 0x74, 0x1a, 0x14, 0x2e, 0x68, 0x65, 0x6c, 0x6c, 0x6f, 0x2e, 0x48, 0x65, 0x6c, 0x6c,
-	0x6f, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x42, 0x0a, 0x5a, 0x08, 0x2e, 0x2f, 0x3b,
-	0x68, 0x65, 0x6c, 0x6c, 0x6f, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
+	0x6f, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x12, 0x44, 0x0a, 0x0b, 0x48, 0x65, 0x6c,
+	0x6c, 0x6f, 0x46, 0x69, 0x65, 0x6c, 0x64, 0x73, 0x12, 0x19, 0x2e, 0x68, 0x65, 0x6c, 0x6c, 0x6f,
+	0x2e, 0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x46, 0x69, 0x65, 0x6c, 0x64, 0x73, 0x52, 0x65, 0x71, 0x75,
+	0x65, 0x73, 0x74, 0x1a, 0x1a, 0x2e, 0x68, 0x65, 0x6c, 0x6c, 0x6f, 0x2e, 0x48, 0x65, 0x6c, 0x6c,
+	0x6f, 0x46, 0x69, 0x65, 0x6c, 0x64, 0x73, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x42,
+	0x0a, 0x5a, 0x08, 0x2e, 0x2f, 0x3b, 0x68, 0x65, 0x6c, 0x6c, 0x6f, 0x62, 0x06, 0x70, 0x72, 0x6f,
+	0x74, 0x6f, 0x33,
 }
 
 var (
@@ -208,19 +314,23 @@ func file_hello_proto_rawDescGZIP() []byte {
 	return file_hello_proto_rawDescData
 }
 
-var file_hello_proto_msgTypes = make([]protoimpl.MessageInfo, 2)
+var file_hello_proto_msgTypes = make([]protoimpl.MessageInfo, 4)
 var file_hello_proto_goTypes = []interface{}{
 	(*HelloRequest)(nil),          // 0: hello.HelloRequest
 	(*HelloResponse)(nil),         // 1: hello.HelloResponse
-	(*timestamppb.Timestamp)(nil), // 2: google.protobuf.Timestamp
+	(*HelloFieldsRequest)(nil),    // 2: hello.HelloFieldsRequest
+	(*HelloFieldsResponse)(nil),   // 3: hello.HelloFieldsResponse
+	(*timestamppb.Timestamp)(nil), // 4: google.protobuf.Timestamp
 }
 var file_hello_proto_depIdxs = []int32{
-	2, // 0: hello.HelloRequest.request_time:type_name -> google.protobuf.Timestamp
-	2, // 1: hello.HelloResponse.create_time:type_name -> google.protobuf.Timestamp
+	4, // 0: hello.HelloRequest.request_time:type_name -> google.protobuf.Timestamp
+	4, // 1: hello.HelloResponse.create_time:type_name -> google.protobuf.Timestamp
 	0, // 2: hello.GrpcTestService.Hello:input_type -> hello.HelloRequest
-	1, // 3: hello.GrpcTestService.Hello:output_type -> hello.HelloResponse
-	3, // [3:4] is the sub-list for method output_type
-	2, // [2:3] is the sub-list for method input_type
+	2, // 3: hello.GrpcTestService.HelloFields:input_type -> hello.HelloFieldsRequest
+	1, // 4: hello.GrpcTestService.Hello:output_type -> hello.HelloResponse
+	3, // 5: hello.GrpcTestService.HelloFields:output_type -> hello.HelloFieldsResponse
+	4, // [4:6] is the sub-list for method output_type
+	2, // [2:4] is the sub-list for method input_type
 	2, // [2:2] is the sub-list for extension type_name
 	2, // [2:2] is the sub-list for extension extendee
 	0, // [0:2] is the sub-list for field type_name
@@ -256,6 +366,30 @@ func file_hello_proto_init() {
 				return nil
 			}
 		}
+		file_hello_proto_msgTypes[2].Exporter = func(v interface{}, i int) interface{} {
+			switch v := v.(*HelloFieldsRequest); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
+		file_hello_proto_msgTypes[3].Exporter = func(v interface{}, i int) interface{} {
+			switch v := v.(*HelloFieldsResponse); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
 	}
 	file_hello_proto_msgTypes[1].OneofWrappers = []interface{}{}
 	type x struct{}
@@ -264,7 +398,7 @@ func file_hello_proto_init() {
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: file_hello_proto_rawDesc,
 			NumEnums:      0,
-			NumMessages:   2,
+			NumMessages:   4,
 			NumExtensions: 0,
 			NumServices:   1,
 		},
diff --git a/testdata/hello/hello_grpc.pb.go b/testdata/hello/hello_grpc.pb.go
index a693966..ad0b388 100644
--- a/testdata/hello/hello_grpc.pb.go
+++ b/testdata/hello/hello_grpc.pb.go
@@ -1,7 +1,7 @@
 // Code generated by protoc-gen-go-grpc. DO NOT EDIT.
 // versions:
 // - protoc-gen-go-grpc v1.3.0
-// - protoc             v3.21.12
+// - protoc             v4.25.3
 // source: hello.proto
 
 package hello
@@ -19,7 +19,8 @@ import (
 const _ = grpc.SupportPackageIsVersion7
 
 const (
-	GrpcTestService_Hello_FullMethodName = "/hello.GrpcTestService/Hello"
+	GrpcTestService_Hello_FullMethodName       = "/hello.GrpcTestService/Hello"
+	GrpcTestService_HelloFields_FullMethodName = "/hello.GrpcTestService/HelloFields"
 )
 
 // GrpcTestServiceClient is the client API for GrpcTestService service.
@@ -27,6 +28,7 @@ const (
 // For semantics around ctx use and closing/ending streaming RPCs, please refer to https://pkg.go.dev/google.golang.org/grpc/?tab=doc#ClientConn.NewStream.
 type GrpcTestServiceClient interface {
 	Hello(ctx context.Context, in *HelloRequest, opts ...grpc.CallOption) (*HelloResponse, error)
+	HelloFields(ctx context.Context, in *HelloFieldsRequest, opts ...grpc.CallOption) (*HelloFieldsResponse, error)
 }
 
 type grpcTestServiceClient struct {
@@ -46,11 +48,21 @@ func (c *grpcTestServiceClient) Hello(ctx context.Context, in *HelloRequest, opt
 	return out, nil
 }
 
+func (c *grpcTestServiceClient) HelloFields(ctx context.Context, in *HelloFieldsRequest, opts ...grpc.CallOption) (*HelloFieldsResponse, error) {
+	out := new(HelloFieldsResponse)
+	err := c.cc.Invoke(ctx, GrpcTestService_HelloFields_FullMethodName, in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
 // GrpcTestServiceServer is the server API for GrpcTestService service.
 // All implementations must embed UnimplementedGrpcTestServiceServer
 // for forward compatibility
 type GrpcTestServiceServer interface {
 	Hello(context.Context, *HelloRequest) (*HelloResponse, error)
+	HelloFields(context.Context, *HelloFieldsRequest) (*HelloFieldsResponse, error)
 	mustEmbedUnimplementedGrpcTestServiceServer()
 }
 
@@ -61,6 +73,9 @@ type UnimplementedGrpcTestServiceServer struct {
 func (UnimplementedGrpcTestServiceServer) Hello(context.Context, *HelloRequest) (*HelloResponse, error) {
 	return nil, status.Errorf(codes.Unimplemented, "method Hello not implemented")
 }
+func (UnimplementedGrpcTestServiceServer) HelloFields(context.Context, *HelloFieldsRequest) (*HelloFieldsResponse, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method HelloFields not implemented")
+}
 func (UnimplementedGrpcTestServiceServer) mustEmbedUnimplementedGrpcTestServiceServer() {}
 
 // UnsafeGrpcTestServiceServer may be embedded to opt out of forward compatibility for this service.
@@ -92,6 +107,24 @@ func _GrpcTestService_Hello_Handler(srv interface{}, ctx context.Context, dec fu
 	return interceptor(ctx, in, info, handler)
 }
 
+func _GrpcTestService_HelloFields_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(HelloFieldsRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(GrpcTestServiceServer).HelloFields(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: GrpcTestService_HelloFields_FullMethodName,
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(GrpcTestServiceServer).HelloFields(ctx, req.(*HelloFieldsRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
 // GrpcTestService_ServiceDesc is the grpc.ServiceDesc for GrpcTestService service.
 // It's only intended for direct use with grpc.RegisterService,
 // and not to be introspected or modified (even as a copy)
@@ -103,6 +136,10 @@ var GrpcTestService_ServiceDesc = grpc.ServiceDesc{
 			MethodName: "Hello",
 			Handler:    _GrpcTestService_Hello_Handler,
 		},
+		{
+			MethodName: "HelloFields",
+			Handler:    _GrpcTestService_HelloFields_Handler,
+		},
 	},
 	Streams:  []grpc.StreamDesc{},
 	Metadata: "hello.proto",
diff --git a/testdata/routeguide/route_guide.pb.go b/testdata/routeguide/route_guide.pb.go
index 5e2d70a..4eb5138 100644
--- a/testdata/routeguide/route_guide.pb.go
+++ b/testdata/routeguide/route_guide.pb.go
@@ -14,8 +14,8 @@
 
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
-// 	protoc-gen-go v1.30.0
-// 	protoc        v3.21.12
+// 	protoc-gen-go v1.33.0
+// 	protoc        v4.25.3
 // source: route_guide.proto
 
 package routeguide
diff --git a/testdata/routeguide/route_guide_grpc.pb.go b/testdata/routeguide/route_guide_grpc.pb.go
index 00b8007..d530eba 100644
--- a/testdata/routeguide/route_guide_grpc.pb.go
+++ b/testdata/routeguide/route_guide_grpc.pb.go
@@ -15,7 +15,7 @@
 // Code generated by protoc-gen-go-grpc. DO NOT EDIT.
 // versions:
 // - protoc-gen-go-grpc v1.3.0
-// - protoc             v3.21.12
+// - protoc             v4.25.3
 // source: route_guide.proto
 
 package routeguide