diff --git a/client_test.go b/client_test.go
index 9041c7a..19b03b1 100644
--- a/client_test.go
+++ b/client_test.go
@@ -7,6 +7,7 @@ import (
 	"log"
 	"testing"
 
+	"github.com/gammazero/workerpool"
 	"github.com/stretchr/testify/require"
 
 	"github.com/xconnio/xconn-go"
@@ -17,7 +18,9 @@ func connect(t *testing.T) *xconn.Session {
 	defer func() { _ = listener.Close() }()
 	address := fmt.Sprintf("ws://%s/ws", listener.Addr().String())
 
-	client := &xconn.Client{}
+	client := &xconn.Client{
+		SerializerSpec: xconn.JSONSerializerSpec,
+	}
 
 	session, err := client.Connect(context.Background(), address, "realm1")
 	require.NoError(t, err)
@@ -54,11 +57,17 @@ func TestRegisterCall(t *testing.T) {
 	require.NotNil(t, reg)
 
 	t.Run("Call", func(t *testing.T) {
-		result, err := session.Call(context.Background(), "foo.bar", nil, nil, nil)
-		require.NoError(t, err)
-		require.NotNil(t, result)
+		wp := workerpool.New(10)
+		for i := 0; i < 100; i++ {
+			wp.Submit(func() {
+				result, err := session.Call(context.Background(), "foo.bar", nil, nil, nil)
+				require.NoError(t, err)
+				require.NotNil(t, result)
+				require.Equal(t, "hello", result.Args[0])
+			})
+		}
 
-		require.Equal(t, "hello", result.Args[0])
+		wp.StopWait()
 	})
 }
 
diff --git a/go.mod b/go.mod
index a04de23..6e61729 100644
--- a/go.mod
+++ b/go.mod
@@ -4,14 +4,16 @@ go 1.20
 
 require (
 	github.com/gammazero/nexus/v3 v3.2.2
+	github.com/gammazero/workerpool v1.1.3
 	github.com/gobwas/ws v1.4.0
 	github.com/stretchr/testify v1.8.4
-	github.com/xconnio/wampproto-go v0.0.0-20240530132134-a9a2ca11944a
+	github.com/xconnio/wampproto-go v0.0.0-20240530202948-a758eb534226
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/fxamacker/cbor/v2 v2.6.0 // indirect
+	github.com/gammazero/deque v0.2.0 // indirect
 	github.com/gobwas/httphead v0.1.0 // indirect
 	github.com/gobwas/pool v0.2.1 // indirect
 	github.com/gorilla/websocket v1.5.0 // indirect
diff --git a/go.sum b/go.sum
index 85e1e7d..08a80c3 100644
--- a/go.sum
+++ b/go.sum
@@ -2,8 +2,12 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fxamacker/cbor/v2 v2.6.0 h1:sU6J2usfADwWlYDAFhZBQ6TnLFBHxgesMrQfQgk1tWA=
 github.com/fxamacker/cbor/v2 v2.6.0/go.mod h1:pxXPTn3joSm21Gbwsv0w9OSA2y1HFR9qXEeXQVeNoDQ=
+github.com/gammazero/deque v0.2.0 h1:SkieyNB4bg2/uZZLxvya0Pq6diUlwx7m2TeT7GAIWaA=
+github.com/gammazero/deque v0.2.0/go.mod h1:LFroj8x4cMYCukHJDbxFCkT+r9AndaJnFMuZDV34tuU=
 github.com/gammazero/nexus/v3 v3.2.2 h1:uEBe4rKIcbBcbdP6XuyKUhnWBXxT0BnJrecG9+yZSTs=
 github.com/gammazero/nexus/v3 v3.2.2/go.mod h1:55oZwPZFgRFCEjpMj1kdzffiPORKKmRsipSY8BeKRvY=
+github.com/gammazero/workerpool v1.1.3 h1:WixN4xzukFoN0XSeXF6puqEqFTl2mECI9S6W44HWy9Q=
+github.com/gammazero/workerpool v1.1.3/go.mod h1:wPjyBLDbyKnUn2XwwyD3EEwo9dHutia9/fwNmSHWACc=
 github.com/gobwas/httphead v0.1.0 h1:exrUm0f4YX0L7EBwZHuCF4GDp8aJfVeBrlLQrs6NqWU=
 github.com/gobwas/httphead v0.1.0/go.mod h1:O/RXo79gxV8G+RqlR/otEwx4Q36zl9rqC5u12GKvMCM=
 github.com/gobwas/pool v0.2.1 h1:xfeeEhW7pwmX8nuLVlqbzVc7udMDrwetjEv+TZIz1og=
@@ -24,8 +28,8 @@ github.com/vmihailenco/tagparser/v2 v2.0.0 h1:y09buUbR+b5aycVFQs/g70pqKVZNBmxwAh
 github.com/vmihailenco/tagparser/v2 v2.0.0/go.mod h1:Wri+At7QHww0WTrCBeu4J6bNtoV6mEfg5OIWRZA9qds=
 github.com/x448/float16 v0.8.4 h1:qLwI1I70+NjRFUR3zs1JPUCgaCXSh3SW62uAKT1mSBM=
 github.com/x448/float16 v0.8.4/go.mod h1:14CWIYCyZA/cWjXOioeEpHeN/83MdbZDRQHoFcYsOfg=
-github.com/xconnio/wampproto-go v0.0.0-20240530132134-a9a2ca11944a h1:0Vb6+/sNho0zn7kjRsdBvdGylFkz9uZZzeT1RrgKHIU=
-github.com/xconnio/wampproto-go v0.0.0-20240530132134-a9a2ca11944a/go.mod h1:BH0AFRLJ9POvVfxsFd9GyvA15U9o0XYQfq8TdkqO2vQ=
+github.com/xconnio/wampproto-go v0.0.0-20240530202948-a758eb534226 h1:1UFs+1ev6G1qDVgf5tGqnhsm5e9btuon41ogyrR1QD4=
+github.com/xconnio/wampproto-go v0.0.0-20240530202948-a758eb534226/go.mod h1:BH0AFRLJ9POvVfxsFd9GyvA15U9o0XYQfq8TdkqO2vQ=
 go.uber.org/goleak v1.2.1 h1:NBol2c7O1ZokfZ0LEU9K6Whx/KnwvepVetCUhtKja4A=
 golang.org/x/crypto v0.23.0 h1:dIJU/v2J8Mdglj/8rJ6UUOM3Zc9zLZxVZwwxMooUSAI=
 golang.org/x/crypto v0.23.0/go.mod h1:CKFgDieR+mRhux2Lsu27y0fO304Db0wZe70UKqHu0v8=
diff --git a/peer.go b/peer.go
index 177a474..86c90b5 100644
--- a/peer.go
+++ b/peer.go
@@ -1,6 +1,9 @@
 package xconn
 
-import "net"
+import (
+	"net"
+	"sync"
+)
 
 func NewBaseSession(id int64, realm, authID, authRole string, cl Peer) BaseSession {
 	return &baseSession{
@@ -80,6 +83,8 @@ type WebSocketPeer struct {
 	conn          net.Conn
 	wsReader      ReaderFunc
 	wsWriter      WriterFunc
+
+	wm sync.Mutex
 }
 
 func (c *WebSocketPeer) Read() ([]byte, error) {
@@ -87,6 +92,9 @@ func (c *WebSocketPeer) Read() ([]byte, error) {
 }
 
 func (c *WebSocketPeer) Write(bytes []byte) error {
+	c.wm.Lock()
+	defer c.wm.Unlock()
+
 	return c.wsWriter(c.conn, bytes)
 }
 
diff --git a/session.go b/session.go
index 75dead8..2188a93 100644
--- a/session.go
+++ b/session.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"sync"
 
 	"github.com/xconnio/wampproto-go"
 	"github.com/xconnio/wampproto-go/messages"
@@ -21,10 +22,10 @@ type Session struct {
 	idGen *wampproto.SessionScopeIDGenerator
 
 	// remote procedure calls data structures
-	registerRequests   map[int64]chan *RegisterResponse
-	unregisterRequests map[int64]chan *UnRegisterResponse
-	registrations      map[int64]InvocationHandler
-	callRequests       map[int64]chan *CallResponse
+	registerRequests   sync.Map
+	unregisterRequests sync.Map
+	registrations      sync.Map
+	callRequests       sync.Map
 
 	// publish subscribe data structures
 	subscribeRequests   map[int64]chan *SubscribeResponse
@@ -39,10 +40,10 @@ func NewSession(base BaseSession, serializer serializers.Serializer) *Session {
 		proto: wampproto.NewSession(serializer),
 		idGen: &wampproto.SessionScopeIDGenerator{},
 
-		registerRequests:   map[int64]chan *RegisterResponse{},
-		unregisterRequests: map[int64]chan *UnRegisterResponse{},
-		registrations:      map[int64]InvocationHandler{},
-		callRequests:       map[int64]chan *CallResponse{},
+		registerRequests:   sync.Map{},
+		unregisterRequests: sync.Map{},
+		registrations:      sync.Map{},
+		callRequests:       sync.Map{},
 
 		subscribeRequests:   map[int64]chan *SubscribeResponse{},
 		unsubscribeRequests: map[int64]chan *UnSubscribeResponse{},
@@ -81,31 +82,35 @@ func (s *Session) processIncomingMessage(msg messages.Message) error {
 	switch msg.Type() {
 	case messages.MessageTypeRegistered:
 		registered := msg.(*messages.Registered)
-		request, exists := s.registerRequests[registered.RequestID()]
+		request, exists := s.registerRequests.Load(registered.RequestID())
 		if !exists {
 			return fmt.Errorf("received REGISTERED for unknown request")
 		}
 
-		request <- &RegisterResponse{msg: registered}
+		requestChan := request.(chan *RegisterResponse)
+		requestChan <- &RegisterResponse{msg: registered}
 	case messages.MessageTypeUnRegistered:
 		unregistered := msg.(*messages.UnRegistered)
-		request, exists := s.unregisterRequests[unregistered.RequestID()]
+		request, exists := s.unregisterRequests.Load(unregistered.RequestID())
 		if !exists {
 			return fmt.Errorf("received UNREGISTERED for unknown request")
 		}
 
-		request <- &UnRegisterResponse{msg: unregistered}
+		requestChan := request.(chan *UnRegisterResponse)
+		requestChan <- &UnRegisterResponse{msg: unregistered}
 	case messages.MessageTypeResult:
 		result := msg.(*messages.Result)
-		request, exists := s.callRequests[result.RequestID()]
+		request, exists := s.callRequests.Load(result.RequestID())
 		if !exists {
 			return fmt.Errorf("received RESULT for unknown request")
 		}
 
-		request <- &CallResponse{msg: result}
+		req := request.(chan *CallResponse)
+		req <- &CallResponse{msg: result}
 	case messages.MessageTypeInvocation:
 		invocation := msg.(*messages.Invocation)
-		endpoint := s.registrations[invocation.RegistrationID()]
+		end, _ := s.registrations.Load(invocation.RegistrationID())
+		endpoint := end.(InvocationHandler)
 
 		inv := &Invocation{
 			Args:    invocation.Args(),
@@ -167,32 +172,31 @@ func (s *Session) processIncomingMessage(msg messages.Message) error {
 		errorMsg := msg.(*messages.Error)
 		switch errorMsg.MessageType() {
 		case messages.MessageTypeCall:
-			responseChan, exists := s.callRequests[errorMsg.RequestID()]
+			response, exists := s.callRequests.LoadAndDelete(errorMsg.RequestID())
 			if !exists {
 				return fmt.Errorf("received ERROR for invalid call request")
 			}
 
-			delete(s.callRequests, errorMsg.RequestID())
 			err := &Error{URI: errorMsg.URI(), Args: errorMsg.Args(), KwArgs: errorMsg.KwArgs()}
+			responseChan := response.(chan *CallResponse)
 			responseChan <- &CallResponse{error: err}
 			return nil
 		case messages.MessageTypeRegister:
-			responseChan, exists := s.registerRequests[errorMsg.RequestID()]
+			request, exists := s.registerRequests.LoadAndDelete(errorMsg.RequestID())
 			if !exists {
 				return fmt.Errorf("received ERROR for invalid register request")
 			}
 
-			delete(s.registerRequests, errorMsg.RequestID())
 			err := &Error{URI: errorMsg.URI(), Args: errorMsg.Args(), KwArgs: errorMsg.KwArgs()}
-			responseChan <- &RegisterResponse{error: err}
+			requestChan := request.(chan *RegisterResponse)
+			requestChan <- &RegisterResponse{error: err}
 			return nil
 		case messages.MessageTypeUnRegister:
-			_, exists := s.unregisterRequests[errorMsg.RequestID()]
+			_, exists := s.unregisterRequests.LoadAndDelete(errorMsg.RequestID())
 			if !exists {
 				return fmt.Errorf("received ERROR for invalid unregister request")
 			}
 
-			delete(s.unregisterRequests, errorMsg.RequestID())
 			return nil
 		case messages.MessageTypeSubscribe:
 			_, exists := s.subscribeRequests[errorMsg.RequestID()]
@@ -238,8 +242,8 @@ func (s *Session) Register(ctx context.Context, procedure string, handler Invoca
 	}
 
 	channel := make(chan *RegisterResponse, 1)
-	s.registerRequests[register.RequestID()] = channel
-	defer delete(s.registerRequests, register.RequestID())
+	s.registerRequests.Store(register.RequestID(), channel)
+	defer s.registerRequests.Delete(register.RequestID())
 
 	if err = s.base.Write(toSend); err != nil {
 		return nil, err
@@ -251,7 +255,7 @@ func (s *Session) Register(ctx context.Context, procedure string, handler Invoca
 			return nil, response.error
 		}
 
-		s.registrations[response.msg.RegistrationID()] = handler
+		s.registrations.Store(response.msg.RegistrationID(), handler)
 		registration := &Registration{
 			ID: response.msg.RegistrationID(),
 		}
@@ -269,8 +273,8 @@ func (s *Session) UnRegister(ctx context.Context, registrationID int64) error {
 	}
 
 	channel := make(chan *UnRegisterResponse, 1)
-	s.unregisterRequests[unregister.RequestID()] = channel
-	defer delete(s.unregisterRequests, unregister.RequestID())
+	s.unregisterRequests.Store(unregister.RequestID(), channel)
+	defer s.unregisterRequests.Delete(unregister.RequestID())
 
 	if err = s.base.Write(toSend); err != nil {
 		return err
@@ -282,7 +286,7 @@ func (s *Session) UnRegister(ctx context.Context, registrationID int64) error {
 			return response.error
 		}
 
-		delete(s.registrations, registrationID)
+		s.registrations.Delete(registrationID)
 		return nil
 	case <-ctx.Done():
 		return fmt.Errorf("unregister request timed")
@@ -299,8 +303,8 @@ func (s *Session) Call(ctx context.Context, procedure string, args []any, kwArgs
 	}
 
 	channel := make(chan *CallResponse, 1)
-	s.callRequests[call.RequestID()] = channel
-	defer delete(s.callRequests, call.RequestID())
+	s.callRequests.Store(call.RequestID(), channel)
+	defer s.callRequests.Delete(call.RequestID())
 	if err = s.base.Write(toSend); err != nil {
 		return nil, err
 	}
diff --git a/types.go b/types.go
index b2eb331..3fb0841 100644
--- a/types.go
+++ b/types.go
@@ -111,12 +111,15 @@ type Result struct {
 }
 
 type Error struct {
-	error
 	URI    string
 	Args   []any
 	KwArgs map[string]any
 }
 
+func (e *Error) Error() string {
+	return e.URI
+}
+
 type RegisterResponse struct {
 	msg   *messages.Registered
 	error *Error