diff --git a/src/app/webApi.cpp b/src/app/webApi.cpp
index 9105949..696c567 100644
--- a/src/app/webApi.cpp
+++ b/src/app/webApi.cpp
@@ -21,17 +21,19 @@ boolean viewByUIDApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc,
 
   if(pSE == NULL)
   {
-    sprintf(buffer, "HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"failed\",\"message\":\"expected UID parameter\"}");
+    strcpy(buffer, "{\"status\":\"failed\",\"message\":\"expected UID parameter\"}");
   }
   else if(strlen(pSE->getString()) > 0)
   {
     if(p->getScreenManager().displayView(atoi(pSE->getString())))
-      sprintf(buffer, "HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"ok\",\"ViewUID\":\"%d\"}", p->getScreenManager().getCurrentViewUID());
+      sprintf(buffer, "{\"status\":\"ok\",\"ViewUID\":\"%d\"}", p->getScreenManager().getCurrentViewUID());
     else
-      sprintf(buffer, "HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"failed\",\"message\":\"%s\"}", p->getScreenManager().getErrorMessage());
+      sprintf(buffer, "{\"status\":\"failed\",\"message\":\"%s\"}", p->getScreenManager().getErrorMessage());
   }
   else
-    sprintf(buffer, "HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"failed\",\"message\":\"UID parameter empty\"}");
+    strcpy(buffer, "{\"status\":\"failed\",\"message\":\"UID parameter empty\"}");
+  
+  WEBServer<WEBClient>::sendHTTPHeader(wc, HttpConstants::httpMIMETypeToString(HttpConstants::APPLICATION_JSON), strlen(buffer));
   wc->print(buffer);
   return true;
 }
@@ -42,12 +44,12 @@ boolean nextViewApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc,
   SAB *p = (SAB *)pData;
   char buffer[200];
   
-  p->getScreenManager().displayNextView();
-  
-  if(p->getScreenManager().getError() == ScreenManager::OK)
-    sprintf(buffer, "HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"ok\",\"ViewUID\":\"%d\"}", p->getScreenManager().getCurrentViewUID());
+  if(p->getScreenManager().displayNextView())
+    sprintf(buffer, "{\"status\":\"ok\",\"ViewUID\":\"%d\"}", p->getScreenManager().getCurrentViewUID());
   else
-    sprintf(buffer, "HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"failed\",\"message\":\"%s\"}", p->getScreenManager().getErrorMessage());
+    sprintf(buffer, "{\"status\":\"failed\",\"message\":\"%s\"}", p->getScreenManager().getErrorMessage());
+  
+  WEBServer<WEBClient>::sendHTTPHeader(wc, HttpConstants::httpMIMETypeToString(HttpConstants::APPLICATION_JSON), strlen(buffer));
   wc->print(buffer);
   return true;
 }
@@ -59,10 +61,11 @@ boolean reloadViewApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc
   char buffer[200];
 
   if(p->getScreenManager().init())
-    strcpy(buffer, "HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"ok\",\"message\":\"config reloaded\"}");
+    strcpy(buffer, "{\"status\":\"ok\",\"message\":\"config reloaded\"}");
   else
-    strcpy(buffer, "HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"failed\",\"message\":\"unable to reload config\"}");
+    strcpy(buffer, "{\"status\":\"failed\",\"message\":\"unable to reload config\"}");
 
+  WEBServer<WEBClient>::sendHTTPHeader(wc, HttpConstants::httpMIMETypeToString(HttpConstants::APPLICATION_JSON), strlen(buffer));
   wc->print(buffer);
   return true;
 }
@@ -88,22 +91,20 @@ boolean rtcSetTimeApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc
   DictionaryHelper::StringEntity *pSE = HRD.getParams("datetime");
   if(pSE == NULL)
   {
-    sprintf(buffer,"HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"failed\",\"message\":\"expected datetime parameter\"}");
+    strcpy(buffer,"{\"status\":\"failed\",\"message\":\"expected datetime parameter\"}");
   }
   else if(strlen(pSE->getString()) > 0)
   {
     Dictionary<DictionaryHelper::StringEntity> *dictio = pSE->split('_');
     if(dictio == NULL)
     {
-      sprintf(buffer,"HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"failed\",\"message\":\"datetime format error\"}");
-      wc->print(buffer);
-      return true;
+      strcpy(buffer,"{\"status\":\"failed\",\"message\":\"datetime format error\"}");
     }
     else
     {
       if(dictio->count() != 6)
       {
-        sprintf(buffer,"HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"error\",\"message\":\"datetime format error\"}"); 
+        strcpy(buffer,"{\"status\":\"error\",\"message\":\"datetime format error\"}"); 
       }
       else
       {
@@ -116,15 +117,16 @@ boolean rtcSetTimeApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc
           atoi(dictio->getAt(5)->getString())
           ));
         DateTime d = p->getRtcManager().getDateTime();
-        sprintf(buffer,"HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"ok\",\"date\":\"%d/%d/%d\",\"time\":\"%d:%d:%d\"}", d.day(), d.month(), d.year(), d.hour(), d.minute(), d.second());
+        sprintf(buffer,"{\"status\":\"ok\",\"date\":\"%d/%d/%d\",\"time\":\"%d:%d:%d\"}", d.day(), d.month(), d.year(), d.hour(), d.minute(), d.second());
       }
-      
-      wc->print(buffer);
       delete dictio;
-      
-      return true;
     }
   }
+  else
+  {
+    strcpy(buffer,"{\"status\":\"failed\",\"message\":\"datetime parameter is empty\"}");
+  }
+  WEBServer<WEBClient>::sendHTTPHeader(wc, HttpConstants::httpMIMETypeToString(HttpConstants::APPLICATION_JSON), strlen(buffer));
   wc->print(buffer);
   return true;
 }
@@ -183,7 +185,8 @@ boolean espRestartApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc
   SAB *sab = (SAB*)pData;
   char  buffer[200];
   
-  sprintf(buffer,"HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"ok\",\"message\":\"module %s in 10 seconds\"}",strstr(HRD.httpResource,"reset") == NULL ? "restarting" : "resetting");
+  sprintf(buffer,"{\"status\":\"ok\",\"message\":\"module %s in 10 seconds\"}",strstr(HRD.httpResource,"reset") == NULL ? "restarting" : "resetting");
+  WEBServer<WEBClient>::sendHTTPHeader(wc, HttpConstants::httpMIMETypeToString(HttpConstants::APPLICATION_JSON), strlen(buffer));
   wc->print(buffer);
   
   sab->getTaskSchedulerManager().addTask(sab->getTaskSchedulerManager().findFreeTaskId(), TaskSchedulerManagerHelper::Schedule::scheduleBuilder()
@@ -206,10 +209,11 @@ boolean sdCardSizeApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc
 	char buffer[200];
 	double size = p->getSdCardManager().getSize(GBYTE);
 	if(size == 0.0)
-		sprintf(buffer,"HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"ok\",\"card\":\"not present\",\"size\":\"0\"}");
+		strcpy(buffer,"{\"status\":\"ok\",\"card\":\"not present\",\"size\":\"0\"}");
 	else
-		sprintf(buffer,"HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"ok\",\"card\":\"present\",\"size\":\"%.2f\",\"unit\":\"GByte\"}",size);
+		sprintf(buffer,"{\"status\":\"ok\",\"card\":\"present\",\"size\":\"%.2f\",\"unit\":\"GByte\"}",size);
 	
+  WEBServer<WEBClient>::sendHTTPHeader(wc, HttpConstants::httpMIMETypeToString(HttpConstants::APPLICATION_JSON), strlen(buffer));
 	wc->print(buffer);
 	return true;
 }
@@ -222,8 +226,8 @@ boolean staWifiInfoApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *w
   IPAddress IP = p->getConnectivityManager().localIP();
  
   sprintf(buffer,"{\"status\":\"ok\",\"RSSI\":%d,\"RSSI2\":%d,\"local IP\":\"%u.%u.%u.%u\",\"mac\":\"%s\"}", p->getConnectivityManager().RSSI(), p->getConnectivityManager().RSSIPercent(), IP[0], IP[1], IP[2], IP[3], p->getConnectivityManager().macAddress().c_str());
-  WEBServer<WEBClient>::sendHTTPHeader(wc, HttpConstants::httpMIMETypeToString(HttpConstants::APPLICATION_JSON), strlen(buffer));
   
+  WEBServer<WEBClient>::sendHTTPHeader(wc, HttpConstants::httpMIMETypeToString(HttpConstants::APPLICATION_JSON), strlen(buffer));
   wc->print(buffer);
 	return true;
 }
@@ -247,7 +251,8 @@ boolean apScannerApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc,
   (void)HRD;
   (void)pData;
   uint8_t number = WiFi.scanNetworks();
-  wc->print("HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n[");
+  WEBServer<WEBClient>::sendHTTPHeader(wc, HttpConstants::httpMIMETypeToString(HttpConstants::APPLICATION_JSON));
+  wc->print("[");
     
   for(uint8_t i(0); i < number; i++)
   {
@@ -283,12 +288,13 @@ boolean powerInfoApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc,
   char buffer[300];
   PowerManager::PowerInfo pi = p->getPowerManager().getPowerInfo();
    
-  sprintf(buffer,"HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"ok\",\"power type\":\"%s\",\"level\":\"%u\",\"unit\":\"%%\"}", pi.powerType == PowerManager::USB ? "USB" : "BAT", pi.level);
+  sprintf(buffer,"{\"status\":\"ok\",\"power type\":\"%s\",\"level\":\"%u\",\"unit\":\"%%\"}", pi.powerType == PowerManager::USB ? "USB" : "BAT", pi.level);
   
+  WEBServer<WEBClient>::sendHTTPHeader(wc, HttpConstants::httpMIMETypeToString(HttpConstants::APPLICATION_JSON), strlen(buffer));
   wc->print(buffer);
   return true;
 }
-
+/* Changing the MCU frequency on the fly isn"t supported anymore by the SDK.
 boolean powerSettingsApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc, void *pData)
 {
   SAB *p = (SAB *)pData;
@@ -321,6 +327,7 @@ boolean powerSettingsApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient
   wc->print(buffer);
   return true;
 }
+*/
 
 boolean ioGetLevelApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc, void *pData)
 {
@@ -330,11 +337,11 @@ boolean ioGetLevelApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc
 
   if(HRD.getParams.count() == 0)//We send every IO state
   {
-    sprintf(buffer,"HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"ok\",\"P0\":\"%d\",\"P1\":\"%d\",\"P2\":\"%d\",\"P3\":\"%d\",\"P4\":\"%d\",\"P5\":\"%d\",\"P6\":\"%d\",\"P7\":\"%d\"}",ioState[0],ioState[1],ioState[2],ioState[3],ioState[4],ioState[5],ioState[6],ioState[7]);
+    sprintf(buffer,"{\"status\":\"ok\",\"P0\":\"%d\",\"P1\":\"%d\",\"P2\":\"%d\",\"P3\":\"%d\",\"P4\":\"%d\",\"P5\":\"%d\",\"P6\":\"%d\",\"P7\":\"%d\"}",ioState[0],ioState[1],ioState[2],ioState[3],ioState[4],ioState[5],ioState[6],ioState[7]);
   }
   else
   {
-    strcpy(buffer,"HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"ok\"");
+    strcpy(buffer,"{\"status\":\"ok\"");
     if(HRD.getParams("P0") != NULL)
     {
       sprintf(helperBuffer,",\"P0\":\"%d\"",ioState[0]);
@@ -378,6 +385,7 @@ boolean ioGetLevelApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc
     strcat(buffer,"}");
   }
 
+  WEBServer<WEBClient>::sendHTTPHeader(wc, HttpConstants::httpMIMETypeToString(HttpConstants::APPLICATION_JSON), strlen(buffer));
   wc->print(buffer);
   return true;
 }
@@ -422,8 +430,9 @@ boolean ioSetLevelApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc
   }
 
   p->getIoManager().getPcf().digitalReadAll(ioState);//We retrieve the IO state
-  sprintf(buffer,"HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"ok\",\"P0\":\"%d\",\"P1\":\"%d\",\"P2\":\"%d\",\"P3\":\"%d\",\"P4\":\"%d\",\"P5\":\"%d\",\"P6\":\"%d\",\"P7\":\"%d\"}",ioState[0],ioState[1],ioState[2],ioState[3],ioState[4],ioState[5],ioState[6],ioState[7]);
+  sprintf(buffer,"{\"status\":\"ok\",\"P0\":\"%d\",\"P1\":\"%d\",\"P2\":\"%d\",\"P3\":\"%d\",\"P4\":\"%d\",\"P5\":\"%d\",\"P6\":\"%d\",\"P7\":\"%d\"}",ioState[0],ioState[1],ioState[2],ioState[3],ioState[4],ioState[5],ioState[6],ioState[7]);
   
+  WEBServer<WEBClient>::sendHTTPHeader(wc, HttpConstants::httpMIMETypeToString(HttpConstants::APPLICATION_JSON), strlen(buffer));
   wc->print(buffer);
   return true;
 }
@@ -440,11 +449,19 @@ boolean ioGetModeApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc,
 
   if(HRD.getParams.count() == 0)//We send every IO mode
   {
-    sprintf(buffer,"HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"ok\",\"P0\":\"%s\",\"P1\":\"%s\",\"P2\":\"%s\",\"P3\":\"%s\",\"P4\":\"%s\",\"P5\":\"%s\",\"P6\":\"%s\",\"P7\":\"%s\"}",ioMode[0] ? OUT:IN,ioMode[1] ? OUT:IN,ioMode[2] ? OUT:IN,ioMode[3] ? OUT:IN,ioMode[4] ? OUT:IN,ioMode[5] ? OUT:IN,ioMode[6] ? OUT:IN,ioMode[7] ? OUT:IN);
+    sprintf(buffer,"{\"status\":\"ok\",\"P0\":\"%s\",\"P1\":\"%s\",\"P2\":\"%s\",\"P3\":\"%s\",\"P4\":\"%s\",\"P5\":\"%s\",\"P6\":\"%s\",\"P7\":\"%s\"}",
+    ioMode[0] ? OUT:IN,
+    ioMode[1] ? OUT:IN,
+    ioMode[2] ? OUT:IN,
+    ioMode[3] ? OUT:IN,
+    ioMode[4] ? OUT:IN,
+    ioMode[5] ? OUT:IN,
+    ioMode[6] ? OUT:IN,
+    ioMode[7] ? OUT:IN);
   }
   else
   {
-    strcpy(buffer,"HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"ok\"");
+    strcpy(buffer,"{\"status\":\"ok\"");
     if(HRD.getParams("P0") != NULL)
     {
       sprintf(helperBuffer,",\"P0\":\"%s\"",ioMode[0] ? OUT:IN);
@@ -488,6 +505,7 @@ boolean ioGetModeApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc,
     strcat(buffer," }");
   }
 
+  WEBServer<WEBClient>::sendHTTPHeader(wc, HttpConstants::httpMIMETypeToString(HttpConstants::APPLICATION_JSON), strlen(buffer));
   wc->print(buffer);
   return true;
 }
@@ -533,8 +551,9 @@ boolean ioSetModeApi(WEBServer<WEBClient>::HttpRequestData &HRD, WiFiClient *wc,
   }
 
   p->getIoManager().getPcf().getPinModeAll(ioMode);//We retrieve the IO modes aka INPUT or OUTPUT
-  sprintf(buffer,"HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"status\":\"ok\",\"P0\":\"%s\",\"P1\":\"%s\",\"P2\":\"%s\",\"P3\":\"%s\",\"P4\":\"%s\",\"P5\":\"%s\",\"P6\":\"%s\",\"P7\":\"%s\"}",ioMode[0] ? OUT:IN,ioMode[1] ? OUT:IN,ioMode[2] ? OUT:IN,ioMode[3] ? OUT:IN,ioMode[4] ? OUT:IN,ioMode[5] ? OUT:IN,ioMode[6] ? OUT:IN,ioMode[7] ? OUT:IN);
+  sprintf(buffer,"{\"status\":\"ok\",\"P0\":\"%s\",\"P1\":\"%s\",\"P2\":\"%s\",\"P3\":\"%s\",\"P4\":\"%s\",\"P5\":\"%s\",\"P6\":\"%s\",\"P7\":\"%s\"}",ioMode[0] ? OUT:IN,ioMode[1] ? OUT:IN,ioMode[2] ? OUT:IN,ioMode[3] ? OUT:IN,ioMode[4] ? OUT:IN,ioMode[5] ? OUT:IN,ioMode[6] ? OUT:IN,ioMode[7] ? OUT:IN);
   
+  WEBServer<WEBClient>::sendHTTPHeader(wc, HttpConstants::httpMIMETypeToString(HttpConstants::APPLICATION_JSON), strlen(buffer));
   wc->print(buffer);
   return true;
 }