diff --git a/src/WebSockets.cpp b/src/WebSockets.cpp
index 60baf2f..5e32a93 100644
--- a/src/WebSockets.cpp
+++ b/src/WebSockets.cpp
@@ -77,12 +77,11 @@ void WebSockets::clientDisconnect(WSclient_t * client, uint16_t code, char * rea
  * @param opcode WSopcode_t
  * @param payload uint8_t *     ptr to the payload
  * @param length size_t         length of the payload
- * @param mask bool             add dummy mask to the frame (needed for web browser)
  * @param fin bool              can be used to send data in more then one frame (set fin on the last frame)
  * @param headerToPayload bool  set true if the payload has reserved 14 Byte at the beginning to dynamically add the Header (payload neet to be in RAM!)
  * @return true if ok
  */
-bool WebSockets::sendFrame(WSclient_t * client, WSopcode_t opcode, uint8_t * payload, size_t length, bool mask, bool fin, bool headerToPayload) {
+bool WebSockets::sendFrame(WSclient_t * client, WSopcode_t opcode, uint8_t * payload, size_t length, bool fin, bool headerToPayload) {
 
     if(client->tcp && !client->tcp->connected()) {
         DEBUG_WEBSOCKETS("[WS][%d][sendFrame] not Connected!?\n", client->num);
@@ -95,7 +94,7 @@ bool WebSockets::sendFrame(WSclient_t * client, WSopcode_t opcode, uint8_t * pay
     }
 
     DEBUG_WEBSOCKETS("[WS][%d][sendFrame] ------- send message frame -------\n", client->num);
-    DEBUG_WEBSOCKETS("[WS][%d][sendFrame] fin: %u opCode: %u mask: %u length: %u headerToPayload: %u\n", client->num, fin, opcode, mask, length, headerToPayload);
+    DEBUG_WEBSOCKETS("[WS][%d][sendFrame] fin: %u opCode: %u mask: %u length: %u headerToPayload: %u\n", client->num, fin, opcode, client->cIsClient, length, headerToPayload);
 
     if(opcode == WSop_text) {
         DEBUG_WEBSOCKETS("[WS][%d][sendFrame] text: %s\n", client->num, (payload + (headerToPayload ? 14 : 0)));
@@ -119,7 +118,7 @@ bool WebSockets::sendFrame(WSclient_t * client, WSopcode_t opcode, uint8_t * pay
         headerSize = 10;
     }
 
-    if(mask) {
+    if(client->cIsClient) {
         headerSize += 4;
     }
 
@@ -158,7 +157,7 @@ bool WebSockets::sendFrame(WSclient_t * client, WSopcode_t opcode, uint8_t * pay
 
     // byte 1
     *headerPtr = 0x00;
-    if(mask) {
+    if(client->cIsClient) {
         *headerPtr |= bit(7);    ///< set mask
     }
 
@@ -194,7 +193,7 @@ bool WebSockets::sendFrame(WSclient_t * client, WSopcode_t opcode, uint8_t * pay
         headerPtr++;
     }
 
-    if(mask) {
+    if(client->cIsClient) {
         if(useInternBuffer) {
             // if we use a Intern Buffer we can modify the data
             // by this fact its possible the do the masking
@@ -434,7 +433,7 @@ void WebSockets::handleWebsocketPayloadCb(WSclient_t * client, bool ok, uint8_t
                 break;
             case WSop_ping:
                 // send pong back
-                sendFrame(client, WSop_pong, payload, header->payloadLen, true);
+                sendFrame(client, WSop_pong, payload, header->payloadLen);
                 break;
             case WSop_pong:
                 DEBUG_WEBSOCKETS("[WS][%d][handleWebsocket] get pong (%s)\n", client->num, payload ? (const char*)payload : "");
diff --git a/src/WebSockets.h b/src/WebSockets.h
index 4063b5f..da88f08 100644
--- a/src/WebSockets.h
+++ b/src/WebSockets.h
@@ -241,6 +241,7 @@ typedef struct {
         String cUrl;        ///< http url
         uint16_t cCode;     ///< http code
 
+        bool cIsClient = false;     ///< will be used for masking
         bool cIsUpgrade;    ///< Connection == Upgrade
         bool cIsWebsocket;  ///< Upgrade == websocket
 
@@ -285,7 +286,7 @@ class WebSockets {
         virtual void messageReceived(WSclient_t * client, WSopcode_t opcode, uint8_t * payload, size_t length, bool fin) = 0;
 
         void clientDisconnect(WSclient_t * client, uint16_t code, char * reason = NULL, size_t reasonLen = 0);
-        bool sendFrame(WSclient_t * client, WSopcode_t opcode, uint8_t * payload = NULL, size_t length = 0, bool mask = false, bool fin = true, bool headerToPayload = false);
+        bool sendFrame(WSclient_t * client, WSopcode_t opcode, uint8_t * payload = NULL, size_t length = 0, bool fin = true, bool headerToPayload = false);
 
         void headerDone(WSclient_t * client);
 
diff --git a/src/WebSocketsClient.cpp b/src/WebSocketsClient.cpp
index b211df2..94ca434 100644
--- a/src/WebSocketsClient.cpp
+++ b/src/WebSocketsClient.cpp
@@ -28,6 +28,7 @@
 WebSocketsClient::WebSocketsClient() {
     _cbEvent = NULL;
     _client.num = 0;
+    _client.cIsClient = true;
     _client.extraHeaders = WEBSOCKETS_STRING("Origin: file://");
 }
 
@@ -194,7 +195,7 @@ bool WebSocketsClient::sendTXT(uint8_t * payload, size_t length, bool headerToPa
         length = strlen((const char *) payload);
     }
     if(clientIsConnected(&_client)) {
-        return sendFrame(&_client, WSop_text, payload, length, true, true, headerToPayload);
+        return sendFrame(&_client, WSop_text, payload, length, true, headerToPayload);
     }
     return false;
 }
@@ -225,7 +226,7 @@ bool WebSocketsClient::sendTXT(String & payload) {
  */
 bool WebSocketsClient::sendBIN(uint8_t * payload, size_t length, bool headerToPayload) {
     if(clientIsConnected(&_client)) {
-        return sendFrame(&_client, WSop_binary, payload, length, true, true, headerToPayload);
+        return sendFrame(&_client, WSop_binary, payload, length, true, headerToPayload);
     }
     return false;
 }
@@ -242,7 +243,7 @@ bool WebSocketsClient::sendBIN(const uint8_t * payload, size_t length) {
  */
 bool WebSocketsClient::sendPing(uint8_t * payload, size_t length) {
     if(clientIsConnected(&_client)) {
-        return sendFrame(&_client, WSop_ping, payload, length, true);
+        return sendFrame(&_client, WSop_ping, payload, length);
     }
     return false;
 }
diff --git a/src/WebSocketsServer.cpp b/src/WebSocketsServer.cpp
index 4bd8536..e1752f2 100644
--- a/src/WebSocketsServer.cpp
+++ b/src/WebSocketsServer.cpp
@@ -184,7 +184,7 @@ bool WebSocketsServer::sendTXT(uint8_t num, uint8_t * payload, size_t length, bo
     }
     WSclient_t * client = &_clients[num];
     if(clientIsConnected(client)) {
-        return sendFrame(client, WSop_text, payload, length, false, true, headerToPayload);
+        return sendFrame(client, WSop_text, payload, length, true, headerToPayload);
     }
     return false;
 }
@@ -222,7 +222,7 @@ bool WebSocketsServer::broadcastTXT(uint8_t * payload, size_t length, bool heade
     for(uint8_t i = 0; i < WEBSOCKETS_SERVER_CLIENT_MAX; i++) {
         client = &_clients[i];
         if(clientIsConnected(client)) {
-            if(!sendFrame(client, WSop_text, payload, length, false, true, headerToPayload)) {
+            if(!sendFrame(client, WSop_text, payload, length, true, headerToPayload)) {
                 ret = false;
             }
         }
@@ -263,7 +263,7 @@ bool WebSocketsServer::sendBIN(uint8_t num, uint8_t * payload, size_t length, bo
     }
     WSclient_t * client = &_clients[num];
     if(clientIsConnected(client)) {
-        return sendFrame(client, WSop_binary, payload, length, false, true, headerToPayload);
+        return sendFrame(client, WSop_binary, payload, length, true, headerToPayload);
     }
     return false;
 }
@@ -285,7 +285,7 @@ bool WebSocketsServer::broadcastBIN(uint8_t * payload, size_t length, bool heade
     for(uint8_t i = 0; i < WEBSOCKETS_SERVER_CLIENT_MAX; i++) {
         client = &_clients[i];
         if(clientIsConnected(client)) {
-            if(!sendFrame(client, WSop_binary, payload, length, false, true, headerToPayload)) {
+            if(!sendFrame(client, WSop_binary, payload, length, true, headerToPayload)) {
                 ret = false;
             }
         }