diff --git a/client/client.go b/client/client.go
index 9ac1d64..409d6c3 100644
--- a/client/client.go
+++ b/client/client.go
@@ -47,7 +47,7 @@ type Client struct {
 	conn  io.ReadWriteCloser
 	codec codec.Codec
 
-	chMtx sync.Mutex
+	chMtx *sync.Mutex
 	chs   map[string]chan *types.Response
 }
 
@@ -57,6 +57,7 @@ func New(conn io.ReadWriteCloser, cf codec.CodecFunc) *Client {
 		conn:  conn,
 		codec: cf(conn),
 		chs:   map[string]chan *types.Response{},
+		chMtx: &sync.Mutex{},
 	}
 
 	go out.handleConn()
@@ -92,7 +93,10 @@ func (c *Client) Call(ctx context.Context, rcvr, method string, arg interface{},
 	}
 
 	// Get response from channel
-	resp := <-c.chs[idStr]
+	c.chMtx.Lock()
+	respCh := c.chs[idStr]
+	c.chMtx.Unlock()
+	resp := <-respCh
 
 	// Close and delete channel
 	c.chMtx.Lock()
@@ -210,11 +214,14 @@ func (c *Client) handleConn() {
 			continue
 		}
 
+		c.chMtx.Lock()
 		// Get channel from map, skip if it doesn't exist
 		ch, ok := c.chs[resp.ID]
 		if !ok {
+			c.chMtx.Unlock()
 			continue
 		}
+		c.chMtx.Unlock()
 
 		// Send response to channel
 		ch <- resp
diff --git a/server/server.go b/server/server.go
index 6a06843..033f632 100644
--- a/server/server.go
+++ b/server/server.go
@@ -280,6 +280,8 @@ func (s *Server) ServeWS(addr string, cf codec.CodecFunc) (err error) {
 
 // handleConn handles a listener connection
 func (s *Server) handleConn(c codec.Codec) {
+	codecMtx := &sync.Mutex{}
+
 	for {
 		var call types.Request
 		// Read request using codec
@@ -322,11 +324,13 @@ func (s *Server) handleConn(c codec.Codec) {
 				go func() {
 					// For every value received from channel
 					for val := range ctx.channel {
+						codecMtx.Lock()
 						// Encode response using codec
 						c.Encode(types.Response{
 							ID:     ctx.channelID,
 							Return: val,
 						})
+						codecMtx.Unlock()
 					}
 
 					// Cancel context
@@ -336,15 +340,19 @@ func (s *Server) handleConn(c codec.Codec) {
 					delete(s.contexts, ctx.channelID)
 					s.contextsMtx.Unlock()
 
+					codecMtx.Lock()
 					c.Encode(types.Response{
 						ID:          ctx.channelID,
 						ChannelDone: true,
 					})
+					codecMtx.Unlock()
 				}()
 			}
 
 			// Encode response using codec
+			codecMtx.Lock()
 			c.Encode(res)
+			codecMtx.Unlock()
 		}
 	}
 }