diff --git a/tasmota/tasmota_xdrv_driver/xdrv_121_gpioviewer.ino b/tasmota/tasmota_xdrv_driver/xdrv_121_gpioviewer.ino
index 1ea345d95..079438c57 100644
--- a/tasmota/tasmota_xdrv_driver/xdrv_121_gpioviewer.ino
+++ b/tasmota/tasmota_xdrv_driver/xdrv_121_gpioviewer.ino
@@ -18,24 +18,24 @@
 #define XDRV_121              121
 
 #ifndef GV_PORT
-#define GV_PORT               5557
+#define GV_PORT               5557         // SSE webserver port
 #endif
 #ifndef GV_SAMPLING_INTERVAL
-#define GV_SAMPLING_INTERVAL  100    // [GvSampling] milliseconds - Use Tasmota Scheduler (100) or Ticker (20..99,101..1000)
+#define GV_SAMPLING_INTERVAL  100          // [GvSampling] milliseconds - Use Tasmota Scheduler (100) or Ticker (20..99,101..1000)
 #endif
 
-#define GV_KEEP_ALIVE         1000   // milliseconds - If no activity after this do a heap size event anyway
+#define GV_KEEP_ALIVE         1000         // milliseconds - If no activity after this do a heap size event anyway
 
 //#define GV_BASE_URL "https://thelastoutpostworkshop.github.io/microcontroller_devkit/gpio_viewer/assets/"
 #ifdef ESP8266
 #ifndef GV_BASE_URL
-#undef GV_BASE_URL                                         // Fix compiler warning
+#undef GV_BASE_URL                         // Fix compiler warning
 #define GV_BASE_URL "https://ota.tasmota.com/tasmota/gpio_viewer/assets/"
 #endif
 #endif  // ESP8266
 #ifdef ESP32
 #ifndef GV_BASE_URL
-#undef GV_BASE_URL                                         // Fix compiler warning
+#undef GV_BASE_URL                         // Fix compiler warning
 #define GV_BASE_URL "https://ota.tasmota.com/tasmota32/gpio_viewer/assets/"
 #endif
 #endif  // ESP32
@@ -49,12 +49,11 @@ const char *GVRelease = "1.0.7";
 #endif
 
 const char HTTP_GV_EVENT[] PROGMEM =
-  // Set CORS headers for global responses
   "HTTP/1.1 200 OK\n"
-  "Content-Type: text/event-stream;\n"
-  "Connection: keep-alive\n"
-  "Cache-Control: no-cache\n"
-  "Access-Control-Allow-Origin: *\n\n";
+  "Content-Type: text/event-stream;\n"     // Server Sent Event protocol
+  "Connection: keep-alive\n"               // Permanent connection
+  "Cache-Control: no-cache\n"              // Do not store data into local cache
+  "Access-Control-Allow-Origin: *\n\n";    // Enable CORS
 
 enum GVPinTypes {
   GV_DigitalPin = 0,
@@ -119,7 +118,7 @@ void GVHandleRoot(void) {
                                         0,                                        
 #endif  // ESP32
                                         ESP_getFreeSketchSpace() / 1024);
-  if (content == nullptr) { return; }                      // Avoid crash
+  if (content == nullptr) { return; }      // Avoid crash
   GV.WebServer->send_P(200, "text/html", content);
   free(content);
 }
@@ -172,8 +171,8 @@ void GVCloseEvent(void) {
 void GVEventSend(const char *message, const char *event, uint32_t id) {
   if (GV.WebClient.connected()) {
     // generateEventMessage() in AsyncEventSource.cpp
-//    GV.WebClient.printf_P(PSTR("retry: 0\r\nid: %u\r\nevent: %s\r\ndata: %s\r\n\r\n"), id, event, message);
-    GV.WebClient.printf_P(PSTR("id: %u\r\nevent: %s\r\ndata: %s\r\n\r\n"), id, event, message);
+//    GV.WebClient.printf_P(PSTR("retry:0\nid:%u\nevent:%s\ndata:%s\n\n"), id, event, message);
+    GV.WebClient.printf_P(PSTR("id:%u\nevent:%s\ndata:%s\n\n"), id, event, message);
   } else {
     GVEventDisconnected();
   }
@@ -299,7 +298,7 @@ void GVMonitorTask(void) {
  * Commands
 \*********************************************************************************************/
 
-const char kGVCommands[] PROGMEM = "GV|"  // Prefix
+const char kGVCommands[] PROGMEM = "GV|"   // Prefix
   "Viewer|Sampling";
 
 void (* const GVCommand[])(void) PROGMEM = {
@@ -313,13 +312,13 @@ void CmndGvViewer(void) {
   */
   if ((XdrvMailbox.payload >= 0) && (XdrvMailbox.payload <= 2)) {
     uint32_t state = XdrvMailbox.payload;
-    if (2 == state) {           // Toggle
+    if (2 == state) {                      // Toggle
       state = GV.active ^1;
     }
-    if (state) {                // On
+    if (state) {                           // On
       GVBegin();
-    } else {                    // Off
-      GVCloseEvent();           // Stop current updates
+    } else {                               // Off
+      GVCloseEvent();                      // Stop current updates
       GVStop();
     }
   }
@@ -335,8 +334,8 @@ void CmndGvSampling(void) {
      GvSampling 20 .. 1000  - Set sampling interval
   */
   if ((XdrvMailbox.payload >= 20) && (XdrvMailbox.payload <= 1000)) {
-    GVCloseEvent();                     // Stop current updates
-    GV.sampling = XdrvMailbox.payload;  // 20 - 1000 milliseconds
+    GVCloseEvent();                        // Stop current updates
+    GV.sampling = XdrvMailbox.payload;     // 20 - 1000 milliseconds
   }
   ResponseCmndNumber(GV.sampling);
 }