diff --git a/.travis.yml b/.travis.yml
index 74e8823..93776c1 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,6 +16,8 @@ before_install:
 install:
   - composer install --no-interaction --prefer-source
   - go get "github.com/spiral/goridge"
+  - cp -r * $GOPATH/src/github.com/spiral/goridge
+  - go get "github.com/pkg/errors"
   - go get "github.com/stretchr/testify/assert"
   - go build tests/server.go
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 21161e2..5d4eee7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,12 @@
 CHANGELOG
 =========
 
+## v2.1.0 (03.06.2018)
+- added golang ClientCodec implementation
+- additional error detections
+- added sequence support
+- more tests
+
 ## v2.0.5 (03.04.2018)
 - handled possible panic on reading from broken connection in socket relay
 
diff --git a/binary.go b/binary.go
new file mode 100644
index 0000000..9157a4a
--- /dev/null
+++ b/binary.go
@@ -0,0 +1,32 @@
+package goridge
+
+import (
+	"bytes"
+	"encoding/binary"
+)
+
+func pack(m string, s uint64) []byte {
+	b := bytes.Buffer{}
+	b.WriteString(m)
+
+	b.Write([]byte{
+		byte(s),
+		byte(s >> 8),
+		byte(s >> 16),
+		byte(s >> 24),
+		byte(s >> 32),
+		byte(s >> 40),
+		byte(s >> 48),
+		byte(s >> 56),
+	})
+
+	return b.Bytes()
+}
+
+func unpack(in []byte, m *string, s *uint64) error {
+	*m = string(in[:len(in)-8])
+	*s = binary.LittleEndian.Uint64(in[len(in)-8:])
+
+	// no errors for now
+	return nil
+}
diff --git a/binary_test.go b/binary_test.go
new file mode 100644
index 0000000..277f20f
--- /dev/null
+++ b/binary_test.go
@@ -0,0 +1,27 @@
+package goridge
+
+import (
+	"testing"
+	"net/rpc"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPackUnpack(t *testing.T) {
+	var (
+		req = &rpc.Request{
+			ServiceMethod: "test.Process",
+			Seq:           199,
+		}
+		res = &rpc.Response{}
+	)
+
+	data := pack(req.ServiceMethod, req.Seq)
+	assert.Len(t, data, len(req.ServiceMethod)+8)
+	assert.NoError(t, unpack(data, &res.ServiceMethod, &res.Seq))
+
+	assert.Equal(t, res.ServiceMethod, req.ServiceMethod)
+	assert.Equal(t, res.Seq, req.Seq)
+
+	assert.Equal(t, "test.Process", res.ServiceMethod)
+	assert.Equal(t, uint64(199), res.Seq)
+}
diff --git a/client.go b/client.go
new file mode 100644
index 0000000..decb5a7
--- /dev/null
+++ b/client.go
@@ -0,0 +1,106 @@
+package goridge
+
+import (
+	"io"
+	"net/rpc"
+	"reflect"
+	"encoding/json"
+	"github.com/pkg/errors"
+)
+
+// Client codec for goridge connection.
+type ClientCodec struct {
+	relay  Relay
+	closed bool
+}
+
+// NewCodec initiates new server rpc codec over socket connection.
+func NewClientCodec(rwc io.ReadWriteCloser) *ClientCodec {
+	return &ClientCodec{relay: NewSocketRelay(rwc)}
+}
+
+// WriteRequest writes request to the connection. Sequential.
+func (c *ClientCodec) WriteRequest(r *rpc.Request, body interface{}) error {
+	if err := c.relay.Send(pack(r.ServiceMethod, r.Seq), PayloadControl|PayloadRaw); err != nil {
+		return err
+	}
+
+	if bin, ok := body.(*[]byte); ok {
+		return c.relay.Send(*bin, PayloadRaw)
+	}
+
+	if bin, ok := body.([]byte); ok {
+		return c.relay.Send(bin, PayloadRaw)
+	}
+
+	packed, err := json.Marshal(body)
+	if err != nil {
+		return err
+	}
+
+	return c.relay.Send(packed, 0)
+}
+
+// ReadResponseHeader reads response from the connection.
+func (c *ClientCodec) ReadResponseHeader(r *rpc.Response) error {
+	data, p, err := c.relay.Receive()
+	if err != nil {
+		return err
+	}
+
+	if !p.HasFlag(PayloadControl) {
+		return errors.New("invalid rpc header, control flag is missing")
+	}
+
+	if !p.HasFlag(PayloadRaw) {
+		return errors.New("rpc response header must be in {rawData}")
+	}
+
+	if !p.HasPayload() {
+		return errors.New("rpc response header can't be empty")
+	}
+
+	return unpack(data, &r.ServiceMethod, &r.Seq)
+}
+
+// ReadResponseBody response from the connection.
+func (c *ClientCodec) ReadResponseBody(out interface{}) error {
+	data, p, err := c.relay.Receive()
+	if err != nil {
+		return err
+	}
+
+	if out == nil {
+		// discarding
+		return nil
+	}
+
+	if !p.HasPayload() {
+		return nil
+	}
+
+	if p.HasFlag(PayloadError) {
+		return errors.New(string(data))
+	}
+
+	if p.HasFlag(PayloadRaw) {
+		if bin, ok := out.(*[]byte); ok {
+			*bin = append(*bin, data...)
+			return nil
+		}
+
+		return errors.New("{rawData} request for " + reflect.ValueOf(out).String())
+	}
+
+	return json.Unmarshal(data, out)
+}
+
+// Close closes the client connection.
+func (c *ClientCodec) Close() error {
+	if c.closed {
+		return nil
+	}
+
+	c.closed = true
+	return c.relay.Close()
+}
diff --git a/client_server_test.go b/client_server_test.go
new file mode 100644
index 0000000..c2f90a4
--- /dev/null
+++ b/client_server_test.go
@@ -0,0 +1,107 @@
+package goridge
+
+import (
+	"testing"
+	"strings"
+	"net"
+	"net/rpc"
+	"github.com/stretchr/testify/assert"
+	"github.com/pkg/errors"
+)
+
+// testService sample
+type testService struct{}
+
+// Payload sample
+type Payload struct {
+	Name  string            `json:"name"`
+	Value int               `json:"value"`
+	Keys  map[string]string `json:"keys,omitempty"`
+}
+
+// Echo returns incoming message
+func (s *testService) Echo(msg string, r *string) error {
+	*r = msg
+	return nil
+}
+
+// Echo returns error
+func (s *testService) EchoR(msg string, r *string) error {
+	return errors.New("echoR error")
+}
+
+// Process performs payload conversion
+func (s *testService) Process(msg Payload, r *Payload) error {
+	r.Name = strings.ToUpper(msg.Name)
+	r.Value = -msg.Value
+
+	if len(msg.Keys) != 0 {
+		r.Keys = make(map[string]string)
+		for n, v := range msg.Keys {
+			r.Keys[v] = n
+		}
+	}
+
+	return nil
+}
+
+// EchoBinary work over binary data
+func (s *testService) EchoBinary(msg []byte, out *[]byte) error {
+	*out = append(*out, msg...)
+
+	return nil
+}
+
+func TestClientServer(t *testing.T) {
+	var ln net.Listener
+	var err error
+
+	ln, err = net.Listen("tcp", ":8079")
+	if err != nil {
+		panic(err)
+	}
+
+	rpc.RegisterName("test", new(testService))
+
+	go func() {
+		for {
+			conn, err := ln.Accept()
+			if err != nil {
+				continue
+			}
+			rpc.ServeCodec(NewCodec(conn))
+		}
+	}()
+
+	conn, err := net.Dial("tcp", ":8079")
+	if err != nil {
+		panic(err)
+	}
+
+	client := rpc.NewClientWithCodec(NewClientCodec(conn))
+	defer client.Close()
+
+	var (
+		rs = ""
+		rp = Payload{}
+		rb = make([]byte, 0)
+	)
+
+	assert.NoError(t, client.Call("test.Process", Payload{
+		Name:  "name",
+		Value: 1000,
+		Keys:  map[string]string{"key": "value"},
+	}, &rp))
+
+	assert.Equal(t, "NAME", rp.Name)
+	assert.Equal(t, -1000, rp.Value)
+	assert.Equal(t, "key", rp.Keys["value"])
+
+	assert.NoError(t, client.Call("test.Echo", "hello", &rs))
+	assert.Equal(t, "hello", rs)
+
+	assert.NoError(t, client.Call("test.EchoBinary", []byte("hello world"), &rb))
+	assert.Equal(t, []byte("hello world"), rb)
+
+	assert.Error(t, client.Call("test.EchoR", "hi", &rs))
+}
diff --git a/codec.go b/codec.go
index 0506e9f..734d9bb 100644
--- a/codec.go
+++ b/codec.go
@@ -27,19 +27,18 @@ func (c *Codec) ReadRequestHeader(r *rpc.Request) error {
 	}
 
 	if !p.HasFlag(PayloadControl) {
-		return errors.New("invalid request, control data is expected")
+		return errors.New("invalid rpc header, control flag is missing")
 	}
 
 	if !p.HasFlag(PayloadRaw) {
-		return errors.New("rpc control command must be in {rawData}")
+		return errors.New("rpc response header must be in {rawData}")
 	}
 
 	if !p.HasPayload() {
-		return nil
+		return errors.New("rpc request header can't be empty")
 	}
 
-	r.ServiceMethod = string(data)
-	return nil
+	return unpack(data, &r.ServiceMethod, &r.Seq)
 }
 
 // ReadRequestBody fetches prefixed body data and automatically unmarshal it as json. RawBody flag will populate
@@ -50,6 +49,11 @@ func (c *Codec) ReadRequestBody(out interface{}) error {
 		return err
 	}
 
+	if out == nil {
+		// discarding
+		return nil
+	}
+
 	if !p.HasPayload() {
 		return nil
 	}
@@ -60,7 +64,7 @@ func (c *Codec) ReadRequestBody(out interface{}) error {
 			return nil
 		}
 
-		return errors.New("{rawData} request for " + reflect.ValueOf(out).Elem().Kind().String())
+		return errors.New("{rawData} request for " + reflect.ValueOf(out).String())
 	}
 
 	return json.Unmarshal(data, out)
@@ -68,6 +72,10 @@ func (c *Codec) ReadRequestBody(out interface{}) error {
 
 // WriteResponse marshals response, byte slice or error to remote party.
 func (c *Codec) WriteResponse(r *rpc.Response, body interface{}) error {
+	if err := c.relay.Send(pack(r.ServiceMethod, r.Seq), PayloadControl|PayloadRaw); err != nil {
+		return err
+	}
+
 	if r.Error != "" {
 		return c.relay.Send([]byte(r.Error), PayloadError|PayloadRaw)
 	}
diff --git a/composer.json b/composer.json
index 15a5510..8248992 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,7 @@
   },
   "autoload": {
     "psr-4": {
-      "Spiral\\Goridge\\": "source/"
+      "Spiral\\Goridge\\": "php-src/"
     }
   },
   "autoload-dev": {
diff --git a/source/Exceptions/GoridgeException.php b/php-src/Exceptions/GoridgeException.php
similarity index 100%
rename from source/Exceptions/GoridgeException.php
rename to php-src/Exceptions/GoridgeException.php
diff --git a/source/Exceptions/InvalidArgumentException.php b/php-src/Exceptions/InvalidArgumentException.php
similarity index 100%
rename from source/Exceptions/InvalidArgumentException.php
rename to php-src/Exceptions/InvalidArgumentException.php
diff --git a/source/Exceptions/PrefixException.php b/php-src/Exceptions/PrefixException.php
similarity index 100%
rename from source/Exceptions/PrefixException.php
rename to php-src/Exceptions/PrefixException.php
diff --git a/source/Exceptions/RPCException.php b/php-src/Exceptions/RPCException.php
similarity index 100%
rename from source/Exceptions/RPCException.php
rename to php-src/Exceptions/RPCException.php
diff --git a/source/Exceptions/RelayException.php b/php-src/Exceptions/RelayException.php
similarity index 100%
rename from source/Exceptions/RelayException.php
rename to php-src/Exceptions/RelayException.php
diff --git a/source/Exceptions/ServiceException.php b/php-src/Exceptions/ServiceException.php
similarity index 100%
rename from source/Exceptions/ServiceException.php
rename to php-src/Exceptions/ServiceException.php
diff --git a/source/Exceptions/TransportException.php b/php-src/Exceptions/TransportException.php
similarity index 100%
rename from source/Exceptions/TransportException.php
rename to php-src/Exceptions/TransportException.php
diff --git a/source/RPC.php b/php-src/RPC.php
similarity index 67%
rename from source/RPC.php
rename to php-src/RPC.php
index b281b63..472acb3 100644
--- a/source/RPC.php
+++ b/php-src/RPC.php
@@ -17,6 +17,11 @@ class RPC
     /** @var Relay */
     private $relay;
 
+    /**
+     * @var int
+     */
+    private $seq;
+
     /**
      * @param Relay $relay
      */
@@ -37,19 +42,41 @@ public function __construct(Relay $relay)
      */
     public function call(string $method, $payload, int $flags = 0)
     {
-        $this->relay->send($method, Relay::PAYLOAD_CONTROL | Relay::PAYLOAD_RAW);
+        $this->relay->send(
+            $method . pack("P", $this->seq),
+            Relay::PAYLOAD_CONTROL | Relay::PAYLOAD_RAW
+        );
 
         if ($flags & Relay::PAYLOAD_RAW) {
             $this->relay->send($payload, $flags);
         } else {
             $body = json_encode($payload);
             if ($body === false) {
-                throw new Exceptions\ServiceException(sprintf("json encode: %s", json_last_error_msg()));
+                throw new Exceptions\ServiceException(sprintf(
+                    "json encode: %s",
+                    json_last_error_msg()
+                ));
             }
 
             $this->relay->send($body);
         }
 
+        $body = $this->relay->receiveSync($flags);
+
+        if (!($flags & Relay::PAYLOAD_CONTROL)) {
+            throw new Exceptions\TransportException("rpc response header is missing");
+        }
+
+        $rpc = unpack("Ps", substr($body, -8));
+        $rpc['m'] = substr($body, 0, -8);
+
+        if ($rpc["m"] != $method || $rpc["s"] != $this->seq) {
+            throw new Exceptions\TransportException("rpc method call mismatch");
+        }
+
+        // request id++
+        $this->seq++;
+
         // wait for the response
         $body = $this->relay->receiveSync($flags);
 
diff --git a/source/RelayInterface.php b/php-src/RelayInterface.php
similarity index 100%
rename from source/RelayInterface.php
rename to php-src/RelayInterface.php
diff --git a/source/SocketRelay.php b/php-src/SocketRelay.php
similarity index 100%
rename from source/SocketRelay.php
rename to php-src/SocketRelay.php
diff --git a/source/StreamRelay.php b/php-src/StreamRelay.php
similarity index 100%
rename from source/StreamRelay.php
rename to php-src/StreamRelay.php
diff --git a/phpunit.xml b/phpunit.xml
index 3fc9fb3..311e196 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -20,7 +20,7 @@
 
     <filter>
         <whitelist>
-            <directory>source</directory>
+            <directory>php-src</directory>
         </whitelist>
     </filter>
 </phpunit>
\ No newline at end of file
diff --git a/socket.go b/socket.go
index 13baa5a..99a80e8 100644
--- a/socket.go
+++ b/socket.go
@@ -78,10 +78,5 @@ func (rl *SocketRelay) Receive() (data []byte, p Prefix, err error) {
 
 // Close the connection.
 func (rl *SocketRelay) Close() error {
-	rl.muw.Lock()
-	rl.mur.Lock()
-	defer rl.muw.Unlock()
-	defer rl.mur.Unlock()
-
 	return rl.rwc.Close()
-}
+}
\ No newline at end of file
diff --git a/tests/Cases/RPCTest.php b/tests/Cases/RPCTest.php
index d29974b..68b2702 100644
--- a/tests/Cases/RPCTest.php
+++ b/tests/Cases/RPCTest.php
@@ -56,7 +56,7 @@ public function testLongEcho()
 
     /**
      * @expectedException \Spiral\Goridge\Exceptions\ServiceException
-     * @expectedExceptionMessageRegExp #error '{rawData} request for string'.*#
+     * @expectedExceptionMessage {rawData} request for <*string Value>
      */
     public function testConvertException()
     {
@@ -120,7 +120,7 @@ public function testPayload()
 
     /**
      * @expectedException \Spiral\Goridge\Exceptions\ServiceException
-     * @expectedExceptionMessageRegExp #error '{rawData} request for struct.*#
+     * @expectedExceptionMessage {rawData} request for <*main.Payload Value>
      */
     public function testBadPayload()
     {
diff --git a/tests/server.go b/tests/server.go
index 98eb1c5..66a98ab 100644
--- a/tests/server.go
+++ b/tests/server.go
@@ -29,12 +29,14 @@ func (s *Service) Ping(msg string, r *string) error {
 	if msg == "ping" {
 		*r = "pong"
 	}
+
 	return nil
 }
 
 // Echo returns incoming message
 func (s *Service) Echo(msg string, r *string) error {
 	*r = msg
+
 	return nil
 }
 
@@ -54,8 +56,8 @@ func (s *Service) Process(msg Payload, r *Payload) error {
 }
 
 // EchoBinary work over binary data
-func (s *Service) EchoBinary(msg []byte, out *[]byte) error {
-	*out = append(*out, msg...)
+func (s *Service) EchoBinary(msg []byte, r *[]byte) error {
+	*r = append(*r, msg...)
 
 	return nil
 }
@@ -80,6 +82,7 @@ func main() {
 		if err != nil {
 			continue
 		}
+
 		go rpc.ServeCodec(goridge.NewCodec(conn))
 	}
 }