diff --git a/kong/plugins/grpc-gateway/deco.lua b/kong/plugins/grpc-gateway/deco.lua
index 66972ee179c..79f97f28c6c 100644
--- a/kong/plugins/grpc-gateway/deco.lua
+++ b/kong/plugins/grpc-gateway/deco.lua
@@ -169,21 +169,42 @@ function deco.new(method, path, protofile)
   }, deco)
 end
 
+local function get_field_type(typ, field)
+  local _, _, field_typ = pb.field(typ, field)
+  return field_typ
+end
+
+local function encode_fix(v, typ)
+  if typ == "bool" then
+    -- special case for URI parameters
+    return v and v ~= "0" and v ~= "false"
+  end
+
+  return v
+end
+
 --[[
   // Set value `v` at `path` in table `t`
   // Path contains value address in dot-syntax. For example:
   // `path="a.b.c"` would lead to `t[a][b][c] = v`.
 ]]
-local function add_to_table( t, path, v )
+local function add_to_table( t, path, v, typ )
   local tab = t -- set up pointer to table root
+  local msg_typ = typ;
   for m in re_gmatch( path , "([^.]+)(\\.)?") do
     local key, dot = m[1], m[2]
+    msg_typ = get_field_type(msg_typ, key)
+
+    -- not argument that we concern with
+    if not msg_typ then
+      return
+    end
 
     if dot then
       tab[key] = tab[key] or {} -- create empty nested table if key does not exist
       tab = tab[key]
     else
-      tab[key] = v
+      tab[key] = encode_fix(v, msg_typ)
     end
   end
 
@@ -241,12 +262,11 @@ function deco:upstream(body)
           // For example: `GET /v1/messages/123456?revision=2&sub.subfield=foo`
           // translates into `payload = { sub = { subfield = "foo" }}`
         ]]--
-        add_to_table( payload, k, v )
+        add_to_table( payload, k, v, self.endpoint.input_type)
       end
     end
   end
   body = grpc_frame(0x0, pb.encode(self.endpoint.input_type, payload))
-
   return body
 end
 
diff --git a/spec/03-plugins/28-grpc-gateway/01-proxy_spec.lua b/spec/03-plugins/28-grpc-gateway/01-proxy_spec.lua
index 21c44cdb544..705fdec53b4 100644
--- a/spec/03-plugins/28-grpc-gateway/01-proxy_spec.lua
+++ b/spec/03-plugins/28-grpc-gateway/01-proxy_spec.lua
@@ -66,7 +66,7 @@ for _, strategy in helpers.each_strategy() do
       local body = res:read_body()
       local data = cjson.decode(body)
 
-      assert.same({reply = "hello john_doe"}, data)
+      assert.same({reply = "hello john_doe", boolean_test = false}, data)
     end)
 
     test("additional binding", function()
@@ -77,11 +77,11 @@ for _, strategy in helpers.each_strategy() do
 
       local data = cjson.decode((res:read_body()))
 
-      assert.same({reply = "hello john_doe"}, data)
+      assert.same({reply = "hello john_doe", boolean_test = false}, data)
     end)
 
     test("removes unbound query args", function()
-      local res, err = proxy_client:get("/v1/messages/john_doe?arg1=1&arg2=2")
+      local res, err = proxy_client:get("/v1/messages/john_doe?arg1=1&arg2.test=2")
 
       assert.equal(200, res.status)
       assert.is_nil(err)
@@ -89,7 +89,54 @@ for _, strategy in helpers.each_strategy() do
       local body = res:read_body()
       local data = cjson.decode(body)
 
-      assert.same({reply = "hello john_doe"}, data)
+      assert.same({reply = "hello john_doe", boolean_test = false}, data)
+    end)
+
+    describe("boolean behavior", function ()
+      test("true", function()
+        local res, err = proxy_client:get("/v1/messages/legacy/john_doe?boolean_test=true")
+        assert.equal(200, res.status)
+        assert.is_nil(err)
+  
+        local body = res:read_body()
+        local data = cjson.decode(body)
+        assert.same({reply = "hello john_doe", boolean_test = true}, data)
+      end)
+  
+      test("false", function()
+        local res, err = proxy_client:get("/v1/messages/legacy/john_doe?boolean_test=false")
+  
+        assert.equal(200, res.status)
+        assert.is_nil(err)
+  
+        local body = res:read_body()
+        local data = cjson.decode(body)
+  
+        assert.same({reply = "hello john_doe", boolean_test = false}, data)
+      end)
+  
+      test("zero", function()
+        local res, err = proxy_client:get("/v1/messages/legacy/john_doe?boolean_test=0")
+  
+        assert.equal(200, res.status)
+        assert.is_nil(err)
+  
+        local body = res:read_body()
+        local data = cjson.decode(body)
+  
+        assert.same({reply = "hello john_doe", boolean_test = false}, data)
+      end)
+  
+      test("non-zero", function()
+        local res, err = proxy_client:get("/v1/messages/legacy/john_doe?boolean_test=1")
+        assert.equal(200, res.status)
+        assert.is_nil(err)
+  
+        local body = res:read_body()
+        local data = cjson.decode(body)
+  
+        assert.same({reply = "hello john_doe", boolean_test = true}, data)
+      end)
     end)
 
     test("unknown path", function()
diff --git a/spec/fixtures/grpc/target/grpc-target.go b/spec/fixtures/grpc/target/grpc-target.go
index 860281ebb01..32995ed5e22 100644
--- a/spec/fixtures/grpc/target/grpc-target.go
+++ b/spec/fixtures/grpc/target/grpc-target.go
@@ -7,9 +7,10 @@ import (
 	"net"
 	"time"
 
+	pb "target/targetservice"
+
 	"google.golang.org/grpc"
 	"google.golang.org/protobuf/types/known/timestamppb"
-	pb "target/targetservice"
 )
 
 const (
@@ -22,7 +23,8 @@ type server struct {
 
 func (s *server) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloResponse, error) {
 	return &pb.HelloResponse{
-		Reply: fmt.Sprintf("hello %s", in.GetGreeting()),
+		Reply:       fmt.Sprintf("hello %s", in.GetGreeting()),
+		BooleanTest: in.GetBooleanTest(),
 	}, nil
 }
 
diff --git a/spec/fixtures/grpc/target/targetservice/targetservice.pb.go b/spec/fixtures/grpc/target/targetservice/targetservice.pb.go
index 1a11c5dd13a..37ab067a9c8 100644
--- a/spec/fixtures/grpc/target/targetservice/targetservice.pb.go
+++ b/spec/fixtures/grpc/target/targetservice/targetservice.pb.go
@@ -1,13 +1,12 @@
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
-// 	protoc-gen-go v1.25.0
-// 	protoc        v3.6.1
+// 	protoc-gen-go v1.25.0-devel
+// 	protoc        v3.12.4
 // source: targetservice.proto
 
 package targetservice
 
 import (
-	proto "github.com/golang/protobuf/proto"
 	timestamp "github.com/golang/protobuf/ptypes/timestamp"
 	_ "google.golang.org/genproto/googleapis/api/annotations"
 	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
@@ -23,16 +22,13 @@ const (
 	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
 )
 
-// This is a compile-time assertion that a sufficiently up-to-date version
-// of the legacy proto package is being used.
-const _ = proto.ProtoPackageIsVersion4
-
 type HelloRequest struct {
 	state         protoimpl.MessageState
 	sizeCache     protoimpl.SizeCache
 	unknownFields protoimpl.UnknownFields
 
-	Greeting string `protobuf:"bytes,1,opt,name=greeting,proto3" json:"greeting,omitempty"`
+	Greeting    string `protobuf:"bytes,1,opt,name=greeting,proto3" json:"greeting,omitempty"`
+	BooleanTest bool   `protobuf:"varint,2,opt,name=boolean_test,json=booleanTest,proto3" json:"boolean_test,omitempty"`
 }
 
 func (x *HelloRequest) Reset() {
@@ -74,12 +70,20 @@ func (x *HelloRequest) GetGreeting() string {
 	return ""
 }
 
+func (x *HelloRequest) GetBooleanTest() bool {
+	if x != nil {
+		return x.BooleanTest
+	}
+	return false
+}
+
 type HelloResponse struct {
 	state         protoimpl.MessageState
 	sizeCache     protoimpl.SizeCache
 	unknownFields protoimpl.UnknownFields
 
-	Reply string `protobuf:"bytes,1,opt,name=reply,proto3" json:"reply,omitempty"`
+	Reply       string `protobuf:"bytes,1,opt,name=reply,proto3" json:"reply,omitempty"`
+	BooleanTest bool   `protobuf:"varint,2,opt,name=boolean_test,json=booleanTest,proto3" json:"boolean_test,omitempty"`
 }
 
 func (x *HelloResponse) Reset() {
@@ -121,6 +125,13 @@ func (x *HelloResponse) GetReply() string {
 	return ""
 }
 
+func (x *HelloResponse) GetBooleanTest() bool {
+	if x != nil {
+		return x.BooleanTest
+	}
+	return false
+}
+
 type BallIn struct {
 	state         protoimpl.MessageState
 	sizeCache     protoimpl.SizeCache
@@ -382,69 +393,74 @@ var file_targetservice_proto_rawDesc = []byte{
 	0x2f, 0x61, 0x6e, 0x6e, 0x6f, 0x74, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x73, 0x2e, 0x70, 0x72, 0x6f,
 	0x74, 0x6f, 0x1a, 0x1f, 0x67, 0x6f, 0x6f, 0x67, 0x6c, 0x65, 0x2f, 0x70, 0x72, 0x6f, 0x74, 0x6f,
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 }
 
 var (
diff --git a/spec/fixtures/grpc/target/targetservice/targetservice_grpc.pb.go b/spec/fixtures/grpc/target/targetservice/targetservice_grpc.pb.go
index 7eb5f4d2d0d..da488e4bed5 100644
--- a/spec/fixtures/grpc/target/targetservice/targetservice_grpc.pb.go
+++ b/spec/fixtures/grpc/target/targetservice/targetservice_grpc.pb.go
@@ -1,4 +1,8 @@
 // Code generated by protoc-gen-go-grpc. DO NOT EDIT.
+// versions:
+// - protoc-gen-go-grpc v1.2.0
+// - protoc             v3.12.4
+// source: targetservice.proto
 
 package targetservice
 
diff --git a/spec/fixtures/grpc/targetservice.proto b/spec/fixtures/grpc/targetservice.proto
index 892736006ed..400722e5605 100644
--- a/spec/fixtures/grpc/targetservice.proto
+++ b/spec/fixtures/grpc/targetservice.proto
@@ -49,10 +49,12 @@ service Bouncer {
 
 message HelloRequest {
   string greeting = 1;
+  bool boolean_test = 2;
 }
 
 message HelloResponse {
   string reply = 1;
+  bool boolean_test = 2;
 }