diff --git a/code/espurna/alexa.cpp b/code/espurna/alexa.cpp
index bbbb6928..83c2dab8 100644
--- a/code/espurna/alexa.cpp
+++ b/code/espurna/alexa.cpp
@@ -105,11 +105,11 @@ void _alexaSettingsMigrate(int version) {
 // -----------------------------------------------------------------------------
 
 void _alexaWebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "alexa");
+    wsPayloadModule(root, PSTR("alexa"));
 }
 
 bool _alexaWebSocketOnKeyCheck(const char * key, JsonVariant&) {
-    return (strncmp(key, "alexa", 5) == 0);
+    return (strncmp_P(key, PSTR("alexa"), 5) == 0);
 }
 
 void _alexaWebSocketOnConnected(JsonObject& root) {
diff --git a/code/espurna/api_common.cpp b/code/espurna/api_common.cpp
index dbdb8965..9f586f82 100644
--- a/code/espurna/api_common.cpp
+++ b/code/espurna/api_common.cpp
@@ -21,11 +21,11 @@ Copyright (C) 2020 by Maxim Prokhorov <prokhorov dot max at outlook dot com>
 namespace {
 
 bool _apiWebSocketOnKeyCheck(const char * key, JsonVariant&) {
-    return (strncmp(key, "api", 3) == 0);
+    return (strncmp_P(key, PSTR("api"), 3) == 0);
 }
 
 void _apiWebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "api");
+    wsPayloadModule(root, PSTR("api"));
 }
 
 void _apiWebSocketOnConnected(JsonObject& root) {
diff --git a/code/espurna/button.cpp b/code/espurna/button.cpp
index a30fbfe8..66ab52b0 100644
--- a/code/espurna/button.cpp
+++ b/code/espurna/button.cpp
@@ -934,7 +934,7 @@ void _buttonRelayAction(size_t id, ButtonAction action) {
 namespace {
 
 void _buttonWebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "btn");
+    wsPayloadModule(root, PSTR("btn"));
 }
 
 void _buttonWebSocketOnConnected(JsonObject& root) {
@@ -944,7 +944,7 @@ void _buttonWebSocketOnConnected(JsonObject& root) {
 }
 
 bool _buttonWebSocketOnKeyCheck(const char * key, JsonVariant&) {
-    return (strncmp(key, "btn", 3) == 0);
+    return (strncmp_P(key, PSTR("btn"), 3) == 0);
 }
 
 } // namespace
diff --git a/code/espurna/curtain_kingart.cpp b/code/espurna/curtain_kingart.cpp
index 7b29838a..06edb2a6 100644
--- a/code/espurna/curtain_kingart.cpp
+++ b/code/espurna/curtain_kingart.cpp
@@ -395,7 +395,7 @@ void _curtainWebSocketOnConnected(JsonObject& root) {
 
 //------------------------------------------------------------------------------
 bool _curtainWebSocketOnKeyCheck(const char * key, JsonVariant& value) {
-    if (strncmp(key, "curtain", strlen("curtain")) == 0) return true;
+    if (strncmp_P(key, PSTR("curtain"), __builtin_strlen("curtain")) == 0) return true;
     return false;
 }
 
@@ -432,7 +432,7 @@ void _curtainWebSocketOnAction(uint32_t client_id, const char * action, JsonObje
 }
 
 void _curtainWebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "curtain");
+    wsPayloadModule(root, PSTR("curtain"));
 }
 
 #endif //WEB_SUPPORT
diff --git a/code/espurna/debug.cpp b/code/espurna/debug.cpp
index 534ef6c4..5a7d6373 100644
--- a/code/espurna/debug.cpp
+++ b/code/espurna/debug.cpp
@@ -544,7 +544,7 @@ void send(const char* message, size_t len, Timestamp timestamp) {
 namespace web {
 
 void onVisible(JsonObject& root) {
-    wsPayloadModule(root, "dbg");
+    wsPayloadModule(root, PSTR("dbg"));
 }
 
 } // namespace web
diff --git a/code/espurna/garland.cpp b/code/espurna/garland.cpp
index dce1d901..59b79490 100644
--- a/code/espurna/garland.cpp
+++ b/code/espurna/garland.cpp
@@ -209,7 +209,7 @@ void setDefault() {
 #if WEB_SUPPORT
 //------------------------------------------------------------------------------
 void _garlandWebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "garland");
+    wsPayloadModule(root, PSTR("garland"));
 }
 
 void _garlandWebSocketOnConnected(JsonObject& root) {
diff --git a/code/espurna/homeassistant.cpp b/code/espurna/homeassistant.cpp
index 51b64d98..370b80c6 100644
--- a/code/espurna/homeassistant.cpp
+++ b/code/espurna/homeassistant.cpp
@@ -975,7 +975,7 @@ namespace web {
 #if WEB_SUPPORT
 
 void onVisible(JsonObject& root) {
-    wsPayloadModule(root, "ha");
+    wsPayloadModule(root, PSTR("ha"));
 }
 
 void onConnected(JsonObject& root) {
diff --git a/code/espurna/influxdb.cpp b/code/espurna/influxdb.cpp
index a987cc2c..7e11dc2c 100644
--- a/code/espurna/influxdb.cpp
+++ b/code/espurna/influxdb.cpp
@@ -133,11 +133,11 @@ void _idbInitClient() {
 // -----------------------------------------------------------------------------
 
 bool _idbWebSocketOnKeyCheck(const char * key, JsonVariant& value) {
-    return (strncmp(key, "idb", 3) == 0);
+    return (strncmp_P(key, PSTR("idb"), 3) == 0);
 }
 
 void _idbWebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "idb");
+    wsPayloadModule(root, PSTR("idb"));
 }
 
 void _idbWebSocketOnConnected(JsonObject& root) {
diff --git a/code/espurna/led.cpp b/code/espurna/led.cpp
index 00c11718..39093225 100644
--- a/code/espurna/led.cpp
+++ b/code/espurna/led.cpp
@@ -1004,7 +1004,7 @@ bool onKeyCheck(const char* key, JsonVariant&) {
 }
 
 void onVisible(JsonObject& root) {
-    wsPayloadModule(root, "led");
+    wsPayloadModule(root, PSTR("led"));
 }
 
 void onConnected(JsonObject& root) {
diff --git a/code/espurna/light.cpp b/code/espurna/light.cpp
index ea7d94e8..34fb6429 100644
--- a/code/espurna/light.cpp
+++ b/code/espurna/light.cpp
@@ -2338,7 +2338,7 @@ void _lightWebSocketStatus(JsonObject& root) {
 }
 
 void _lightWebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "light");
+    wsPayloadModule(root, PSTR("light"));
 }
 
 void _lightWebSocketOnConnected(JsonObject& root) {
diff --git a/code/espurna/lightfox.cpp b/code/espurna/lightfox.cpp
index 4a15c4c4..12ab6d33 100644
--- a/code/espurna/lightfox.cpp
+++ b/code/espurna/lightfox.cpp
@@ -138,7 +138,7 @@ size_t _lightfox_buttons { 0 };
 #if WEB_SUPPORT
 
 void _lightfoxWebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "lightfox");
+    wsPayloadModule(root, PSTR("lightfox"));
 }
 
 void _lightfoxWebSocketOnAction(uint32_t client_id, const char * action, JsonObject& data) {
diff --git a/code/espurna/mqtt.cpp b/code/espurna/mqtt.cpp
index 8d2c4244..b21f34ff 100644
--- a/code/espurna/mqtt.cpp
+++ b/code/espurna/mqtt.cpp
@@ -910,9 +910,9 @@ bool _mqttWebSocketOnKeyCheck(const char * key, JsonVariant&) {
 }
 
 void _mqttWebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "mqtt");
+    wsPayloadModule(root, PSTR("mqtt"));
 #if SECURE_CLIENT != SECURE_CLIENT_NONE
-    wsPayloadModule(root, "mqttssl");
+    wsPayloadModule(root, PSTR("mqttssl"));
 #endif
 }
 
diff --git a/code/espurna/nofuss.cpp b/code/espurna/nofuss.cpp
index 2735bc85..b4989c8d 100644
--- a/code/espurna/nofuss.cpp
+++ b/code/espurna/nofuss.cpp
@@ -29,11 +29,11 @@ bool _nofussEnabled = false;
 #if WEB_SUPPORT
 
 bool _nofussWebSocketOnKeyCheck(const char * key, JsonVariant& value) {
-    return (strncmp(key, "nofuss", 6) == 0);
+    return (strncmp_P(key, PSTR("nofuss"), 6) == 0);
 }
 
 void _nofussWebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "nofuss");
+    wsPayloadModule(root, PSTR("nofuss"));
 }
 
 void _nofussWebSocketOnConnected(JsonObject& root) {
diff --git a/code/espurna/ntp.cpp b/code/espurna/ntp.cpp
index 419f9ae6..31abde30 100644
--- a/code/espurna/ntp.cpp
+++ b/code/espurna/ntp.cpp
@@ -380,11 +380,11 @@ time_t now() {
 namespace web {
 
 bool onKeyCheck(const char * key, JsonVariant&) {
-    return (strncmp(key, "ntp", 3) == 0);
+    return (strncmp_P(key, PSTR("ntp"), 3) == 0);
 }
 
 void onVisible(JsonObject& root) {
-    wsPayloadModule(root, "ntp");
+    wsPayloadModule(root, PSTR("ntp"));
 }
 
 void onData(JsonObject& root) {
diff --git a/code/espurna/ota_web.cpp b/code/espurna/ota_web.cpp
index d5b54555..435e7ca0 100644
--- a/code/espurna/ota_web.cpp
+++ b/code/espurna/ota_web.cpp
@@ -20,29 +20,30 @@ namespace web {
 namespace {
 
 void onVisible(JsonObject& root) {
-    wsPayloadModule(root, "ota");
+    wsPayloadModule(root, PSTR("ota"));
 }
 
 void sendResponse(AsyncWebServerRequest *request, int code, const String& payload = "") {
-    auto *response = request->beginResponseStream("text/plain", 256);
-    response->addHeader("Connection", "close");
-    response->addHeader("X-XSS-Protection", "1; mode=block");
-    response->addHeader("X-Content-Type-Options", "nosniff");
-    response->addHeader("X-Frame-Options", "deny");
+    auto *response = request->beginResponseStream(F("text/plain"), 256);
+
+    response->addHeader(F("Connection"), F("close"));
+    response->addHeader(F("X-XSS-Protection"), F("1; mode=block"));
+    response->addHeader(F("X-Content-Type-Options"), F("nosniff"));
+    response->addHeader(F("X-Frame-Options"), F("deny"));
 
     response->setCode(code);
 
     if (payload.length()) {
-        response->printf("%s", payload.c_str());
+        response->print(payload);
     } else {
         if (!Update.hasError()) {
-            response->print("OK");
+            response->print(F("OK"));
         } else {
-            #if defined(ARDUINO_ESP8266_RELEASE_2_3_0)
-                Update.printError(reinterpret_cast<Stream&>(response));
-            #else
-                Update.printError(*response);
-            #endif
+#if defined(ARDUINO_ESP8266_RELEASE_2_3_0)
+            Update.printError(reinterpret_cast<Stream&>(response));
+#else
+            Update.printError(*response);
+#endif
         }
     }
 
diff --git a/code/espurna/relay.cpp b/code/espurna/relay.cpp
index ad071b3e..9d17f4bd 100644
--- a/code/espurna/relay.cpp
+++ b/code/espurna/relay.cpp
@@ -2201,14 +2201,14 @@ void _relayWebSocketOnVisible(JsonObject& root) {
     }
 
     if (relays > 1) {
-        wsPayloadModule(root, "multirelay");
+        wsPayloadModule(root, PSTR("multirelay"));
         root[FPSTR(espurna::relay::settings::keys::Sync)] =
             ::settings::internal::serialize(espurna::relay::settings::syncMode());
         root[FPSTR(espurna::relay::settings::keys::Interlock)] =
             espurna::relay::settings::interlockDelay().count();
     }
 
-    wsPayloadModule(root, "relay");
+    wsPayloadModule(root, PSTR("relay"));
 }
 
 void _relayWebSocketOnConnected(JsonObject& root) {
diff --git a/code/espurna/rfbridge.cpp b/code/espurna/rfbridge.cpp
index ce8848cd..4eb48e88 100644
--- a/code/espurna/rfbridge.cpp
+++ b/code/espurna/rfbridge.cpp
@@ -392,9 +392,9 @@ String _rfbRetrieve(size_t id, bool status) {
 #if WEB_SUPPORT
 
 void _rfbWebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "rfb");
+    wsPayloadModule(root, PSTR("rfb"));
 #if RFB_PROVIDER == RFB_PROVIDER_RCSWITCH
-    wsPayloadModule(root, "rfbdirect");
+    wsPayloadModule(root, PSTR("rfbdirect"));
 #endif
 }
 
diff --git a/code/espurna/rfm69.cpp b/code/espurna/rfm69.cpp
index 732ab59f..a100678a 100644
--- a/code/espurna/rfm69.cpp
+++ b/code/espurna/rfm69.cpp
@@ -216,7 +216,7 @@ void _rfm69Clear() {
 #if WEB_SUPPORT
 
 void _rfm69WebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "rfm69");
+    wsPayloadModule(root, PSTR("rfm69"));
 }
 
 void _rfm69WebSocketOnConnected(JsonObject& root) {
diff --git a/code/espurna/rpnrules.cpp b/code/espurna/rpnrules.cpp
index 763e87f1..86e0d89a 100644
--- a/code/espurna/rpnrules.cpp
+++ b/code/espurna/rpnrules.cpp
@@ -354,12 +354,12 @@ void setup() {
 #if WEB_SUPPORT
 namespace web {
 
-void onVisible(JsonObject& root) {
-    wsPayloadModule(root, "rpn");
+bool onKeyCheck(const char * key, JsonVariant& value) {
+    return strncmp_P(key, PSTR("rpn"), 3) == 0;
 }
 
-bool onKeyCheck(const char * key, JsonVariant& value) {
-    return (strncmp(key, "rpn", 3) == 0);
+void onVisible(JsonObject& root) {
+    wsPayloadModule(root, PSTR("rpn"));
 }
 
 void onConnected(JsonObject& root) {
diff --git a/code/espurna/scheduler.cpp b/code/espurna/scheduler.cpp
index b6dea249..4f462918 100644
--- a/code/espurna/scheduler.cpp
+++ b/code/espurna/scheduler.cpp
@@ -511,12 +511,12 @@ namespace web {
 #if WEB_SUPPORT
 
 bool onKey(const char* key, JsonVariant&) {
-    return (strncmp(key, "sch", 3) == 0);
+    return strncmp_P(key, PSTR("sch"), 3) == 0;
 }
 
 void onVisible(JsonObject& root) {
     if (schedulable()) {
-        wsPayloadModule(root, "sch");
+        wsPayloadModule(root, PSTR("sch"));
     }
 }
 
diff --git a/code/espurna/sensor.cpp b/code/espurna/sensor.cpp
index ef0fa0c9..2918dc7b 100644
--- a/code/espurna/sensor.cpp
+++ b/code/espurna/sensor.cpp
@@ -2198,38 +2198,38 @@ void _sensorWebSocketOnAction(uint32_t client_id, const char* action, JsonObject
 }
 
 void _sensorWebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "sns");
+    wsPayloadModule(root, PSTR("sns"));
     for (auto sensor : _sensors) {
         if (_sensorIsEmon(sensor)) {
-            wsPayloadModule(root, "emon");
+            wsPayloadModule(root, PSTR("emon"));
         }
 
         switch (sensor->id()) {
 #if HLW8012_SUPPORT
         case SENSOR_HLW8012_ID:
-            wsPayloadModule(root, "hlw");
+            wsPayloadModule(root, PSTR("hlw"));
             break;
 #endif
 #if CSE7766_SUPPORT
         case SENSOR_CSE7766_ID:
-            wsPayloadModule(root, "cse");
+            wsPayloadModule(root, PSTR("cse"));
             break;
 #endif
 #if PZEM004T_SUPPORT || PZEM004TV30_SUPPORT
         case SENSOR_PZEM004T_ID:
         case SENSOR_PZEM004TV30_ID:
-            wsPayloadModule(root, "pzem");
+            wsPayloadModule(root, PSTR("pzem"));
             break;
 #endif
 #if PULSEMETER_SUPPORT
         case SENSOR_PULSEMETER_ID:
-            wsPayloadModule(root, "pm");
+            wsPayloadModule(root, PSTR("pm"));
             break;
 #endif
 #if MICS2710_SUPPORT || MICS5525_SUPPORT
         case SENSOR_MICS2710_ID:
         case SENSOR_MICS5525_ID:
-            wsPayloadModule(root, "mics");
+            wsPayloadModule(root, PSTR("mics"));
             break;
 #endif
         }
diff --git a/code/espurna/telnet.cpp b/code/espurna/telnet.cpp
index ef32de55..d6e1a624 100644
--- a/code/espurna/telnet.cpp
+++ b/code/espurna/telnet.cpp
@@ -97,12 +97,12 @@ bool _telnetClientsAuth[TELNET_MAX_CLIENTS];
 
 #if WEB_SUPPORT
 
-void _telnetWebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "telnet");
+bool _telnetWebSocketOnKeyCheck(const char * key, JsonVariant&) {
+    return strncmp_P(key, PSTR("telnet"), 6) == 0;
 }
 
-bool _telnetWebSocketOnKeyCheck(const char * key, JsonVariant&) {
-    return (strncmp(key, "telnet", 6) == 0);
+void _telnetWebSocketOnVisible(JsonObject& root) {
+    wsPayloadModule(root, PSTR("telnet"));
 }
 
 void _telnetWebSocketOnConnected(JsonObject& root) {
diff --git a/code/espurna/terminal.cpp b/code/espurna/terminal.cpp
index cdc76f28..662fd57d 100644
--- a/code/espurna/terminal.cpp
+++ b/code/espurna/terminal.cpp
@@ -661,21 +661,17 @@ void _terminalMqttSetup() {
 
 #if WEB_SUPPORT
 
-void _terminalWebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "cmd");
-}
-
 void _terminalWebSocketOnAction(uint32_t, const char* action, JsonObject& data) {
-    if (strcmp(action, "cmd") != 0) {
+    if (strncmp_P(action, PSTR("cmd"), 3) != 0) {
         return;
     }
 
-    alignas(4) static constexpr char key[] PROGMEM = "line";
-    if (!data.containsKey(FPSTR(key)) || !data[FPSTR(key)].is<String>()) {
+    alignas(4) static constexpr char Key[] PROGMEM = "line";
+    if (!data.containsKey(FPSTR(Key)) || !data[FPSTR(Key)].is<String>()) {
         return;
     }
 
-    const auto command = data[FPSTR(key)].as<String>();
+    const auto command = data[FPSTR(Key)].as<String>();
     if (command.length()) {
         _io.inject(command.c_str(), command.length());
         if (command[command.length() - 1] != '\n') {
@@ -684,6 +680,10 @@ void _terminalWebSocketOnAction(uint32_t, const char* action, JsonObject& data)
     }
 }
 
+void _terminalWebSocketOnVisible(JsonObject& root) {
+    wsPayloadModule(root, PSTR("cmd"));
+}
+
 #endif
 
 } // namespace
diff --git a/code/espurna/thermostat.cpp b/code/espurna/thermostat.cpp
index 0dec48bf..4ca3c6ff 100644
--- a/code/espurna/thermostat.cpp
+++ b/code/espurna/thermostat.cpp
@@ -779,7 +779,7 @@ void displayLoop() {
 #if WEB_SUPPORT
 //------------------------------------------------------------------------------
 void _thermostatWebSocketOnVisible(JsonObject& root) {
-    wsPayloadModule(root, "thermostat");
+    wsPayloadModule(root, PSTR("thermostat"));
 }
 
 void _thermostatWebSocketOnConnected(JsonObject& root) {
diff --git a/code/espurna/ws.h b/code/espurna/ws.h
index d4017769..caeb63f1 100644
--- a/code/espurna/ws.h
+++ b/code/espurna/ws.h
@@ -110,8 +110,7 @@ bool wsConnected(uint32_t client_id);
 
 // Append module's name that webui can make it's widgets visible
 // (for the payload in `on_send` callback(s))
-
-void wsPayloadModule(JsonObject& root, const char* const name);
+void wsPayloadModule(JsonObject& root, const char* name);
 
 // Access to our module-specific lifetime callbacks.
 // Expected usage is through the on() methods