diff --git a/sonoff/i18n.h b/sonoff/i18n.h
index ded4ccd43..ca5e2b79a 100644
--- a/sonoff/i18n.h
+++ b/sonoff/i18n.h
@@ -506,14 +506,14 @@ const char S_JSON_COMMAND_INDEX_ASTERIX[] PROGMEM =           "{\"%s%d\":\"" D_A
 const char S_JSON_COMMAND_INDEX_SVALUE_SVALUE[] PROGMEM =     "{\"%s%d\":\"%s%s\"}";
 const char S_JSON_COMMAND_INDEX_NVALUE_ACTIVE_NVALUE[] PROGMEM = "{\"%s%d\":\"%d (" D_JSON_ACTIVE " %d)\"}";
 
-const char S_JSON_SENSOR_INDEX_NVALUE[] PROGMEM =            "{\"" D_CMND_SENSOR "%d\":%d}";
-const char S_JSON_SENSOR_INDEX_SVALUE[] PROGMEM =            "{\"" D_CMND_SENSOR "%d\":\"%s\"}";
+const char S_JSON_SENSOR_INDEX_NVALUE[] PROGMEM =             "{\"" D_CMND_SENSOR "%d\":%d}";
+const char S_JSON_SENSOR_INDEX_SVALUE[] PROGMEM =             "{\"" D_CMND_SENSOR "%d\":\"%s\"}";
 
-const char S_JSON_DRIVER_INDEX_NVALUE[] PROGMEM =            "{\"" D_CMND_DRIVER "%d\":%d}";
-const char S_JSON_DRIVER_INDEX_SVALUE[] PROGMEM =            "{\"" D_CMND_DRIVER "%d\":\"%s\"}";
+const char S_JSON_DRIVER_INDEX_NVALUE[] PROGMEM =             "{\"" D_CMND_DRIVER "%d\":%d}";
+const char S_JSON_DRIVER_INDEX_SVALUE[] PROGMEM =             "{\"" D_CMND_DRIVER "%d\":\"%s\"}";
 
-const char JSON_SNS_TEMP[] PROGMEM = "%s,\"%s\":{\"" D_JSON_TEMPERATURE "\":%s}";
-const char JSON_SNS_TEMPHUM[] PROGMEM = "%s,\"%s\":{\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s}";
+const char JSON_SNS_TEMP[] PROGMEM = ",\"%s\":{\"" D_JSON_TEMPERATURE "\":%s}";
+const char JSON_SNS_TEMPHUM[] PROGMEM = ",\"%s\":{\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s}";
 
 const char S_LOG_I2C_FOUND_AT[] PROGMEM = D_LOG_I2C "%s " D_FOUND_AT " 0x%x";
 
diff --git a/sonoff/sonoff.ino b/sonoff/sonoff.ino
index cf11abcff..458b12ed6 100755
--- a/sonoff/sonoff.ino
+++ b/sonoff/sonoff.ino
@@ -1207,7 +1207,7 @@ void MqttDataHandler(char* topic, uint8_t* data, unsigned int data_len)
         snprintf_P(stemp1, sizeof(stemp1), kWifiConfig[Settings.sta_config]);
         Response_P(PSTR("{\"" D_CMND_WIFICONFIG "\":\"%s " D_JSON_SELECTED "\"}"), stemp1);
         if (WifiState() > WIFI_RESTART) {
-//          snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s after restart"), mqtt_data);
+//          ResponseAppend_P(PSTR(" after restart"));
           restart_flag = 2;
         }
       } else {
@@ -1478,7 +1478,7 @@ bool SendKey(uint8_t key, uint8_t device, uint8_t state)
 #endif  // USE_DOMOTICZ
     result = !Settings.flag3.button_switch_force_local;
   } else {
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("{\"%s%d\":{\"State\":%d}}"), (key) ? "Switch" : "Button", device, state);
+    Response_P(PSTR("{\"%s%d\":{\"State\":%d}}"), (key) ? "Switch" : "Button", device, state);
     result = XdrvRulesProcess();
   }
 #ifdef USE_KNX
diff --git a/sonoff/xdrv_09_timers.ino b/sonoff/xdrv_09_timers.ino
index adaaf0603..59d9300f4 100644
--- a/sonoff/xdrv_09_timers.ino
+++ b/sonoff/xdrv_09_timers.ino
@@ -287,7 +287,7 @@ void TimerEverySecond(void)
               Settings.timer[i].arm = xtimer.repeat;
 #ifdef USE_RULES
               if (3 == xtimer.power) {  // Blink becomes Rule disregarding device and allowing use of Backlog commands
-                snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("{\"Clock\":{\"Timer\":%d}}"), i +1);
+                Response_P(PSTR("{\"Clock\":{\"Timer\":%d}}"), i +1);
                 XdrvRulesProcess();
               } else
 #endif  // USE_RULES
diff --git a/sonoff/xsns_01_counter.ino b/sonoff/xsns_01_counter.ino
index 901793fec..eadd9a4b9 100644
--- a/sonoff/xsns_01_counter.ino
+++ b/sonoff/xsns_01_counter.ino
@@ -107,11 +107,11 @@ void CounterShow(bool json)
 
       if (json) {
         if (!header) {
-          snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"COUNTER\":{"), mqtt_data);
+          ResponseAppend_P(PSTR(",\"COUNTER\":{"));
           stemp[0] = '\0';
         }
         header++;
-        snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s%s\"C%d\":%s"), mqtt_data, stemp, i +1, counter);
+        ResponseAppend_P(PSTR("%s\"C%d\":%s"), stemp, i +1, counter);
         strlcpy(stemp, ",", sizeof(stemp));
 #ifdef USE_DOMOTICZ
         if ((0 == tele_period) && (1 == dsxflg)) {
@@ -131,7 +131,7 @@ void CounterShow(bool json)
   }
   if (json) {
     if (header) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s}"), mqtt_data);
+      ResponseAppend_P(PSTR("}"));
     }
   }
 }
diff --git a/sonoff/xsns_02_analog.ino b/sonoff/xsns_02_analog.ino
index 79a622f0f..9c6c5074e 100644
--- a/sonoff/xsns_02_analog.ino
+++ b/sonoff/xsns_02_analog.ino
@@ -44,7 +44,7 @@ void AdcEvery250ms(void)
   if ((new_value < adc_last_value -10) || (new_value > adc_last_value +10)) {
     adc_last_value = new_value;
     uint16_t value = adc_last_value / 10;
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("{\"ANALOG\":{\"A0div10\":%d}}"), (value > 99) ? 100 : value);
+    Response_P(PSTR("{\"ANALOG\":{\"A0div10\":%d}}"), (value > 99) ? 100 : value);
     XdrvRulesProcess();
   }
 }
@@ -55,7 +55,7 @@ void AdcShow(bool json)
   uint16_t analog = AdcRead();
 
   if (json) {
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"ANALOG\":{\"A0\":%d}"), mqtt_data, analog);
+    ResponseAppend_P(PSTR(",\"ANALOG\":{\"A0\":%d}"), analog);
 #ifdef USE_WEBSERVER
   } else {
     WSContentSend_PD(HTTP_SNS_ANALOG, "", 0, analog);
diff --git a/sonoff/xsns_04_snfsc.ino b/sonoff/xsns_04_snfsc.ino
index 98d1f6276..051640f63 100644
--- a/sonoff/xsns_04_snfsc.ino
+++ b/sonoff/xsns_04_snfsc.ino
@@ -120,8 +120,8 @@ void SonoffScShow(bool json)
     dtostrfd(h, Settings.flag2.humidity_resolution, humidity);
 
     if (json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"SonoffSC\":{\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s,\"" D_JSON_LIGHT "\":%d,\"" D_JSON_NOISE "\":%d,\"" D_JSON_AIRQUALITY "\":%d}"),
-        mqtt_data, temperature, humidity, sc_value[2], sc_value[3], sc_value[4]);
+      ResponseAppend_P(PSTR(",\"SonoffSC\":{\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s,\"" D_JSON_LIGHT "\":%d,\"" D_JSON_NOISE "\":%d,\"" D_JSON_AIRQUALITY "\":%d}"),
+        temperature, humidity, sc_value[2], sc_value[3], sc_value[4]);
 #ifdef USE_DOMOTICZ
       if (0 == tele_period) {
         DomoticzTempHumSensor(temperature, humidity);
diff --git a/sonoff/xsns_05_ds18b20.ino b/sonoff/xsns_05_ds18b20.ino
index 9e82a8e9b..d68664570 100644
--- a/sonoff/xsns_05_ds18b20.ino
+++ b/sonoff/xsns_05_ds18b20.ino
@@ -205,7 +205,7 @@ void Ds18b20Show(bool json)
     char temperature[33];
     dtostrfd(ds18b20_temperature, Settings.flag2.temperature_resolution, temperature);
     if(json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), JSON_SNS_TEMP, mqtt_data, ds18b20_types, temperature);
+      ResponseAppend_P(JSON_SNS_TEMP, ds18b20_types, temperature);
 #ifdef USE_DOMOTICZ
       if (0 == tele_period) {
         DomoticzSensor(DZ_TEMP, temperature);
diff --git a/sonoff/xsns_05_ds18x20.ino b/sonoff/xsns_05_ds18x20.ino
index e2ff0767c..7a67f80a9 100644
--- a/sonoff/xsns_05_ds18x20.ino
+++ b/sonoff/xsns_05_ds18x20.ino
@@ -432,13 +432,13 @@ void Ds18x20Show(bool json)
 
       if (json) {
         if (1 == ds18x20_sensors) {
-          snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_TEMPERATURE "\":%s}"), mqtt_data, ds18x20_types, temperature);
+          ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_TEMPERATURE "\":%s}"), ds18x20_types, temperature);
         } else {
           char address[17];
           for (uint8_t j = 0; j < 6; j++) {
             sprintf(address+2*j, "%02X", ds18x20_sensor[index].address[6-j]);  // Skip sensor type and crc
           }
-          snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_ID "\":\"%s\",\"" D_JSON_TEMPERATURE "\":%s}"), mqtt_data, ds18x20_types, address, temperature);
+          ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_ID "\":\"%s\",\"" D_JSON_TEMPERATURE "\":%s}"), ds18x20_types, address, temperature);
         }
 #ifdef USE_DOMOTICZ
         if ((0 == tele_period) && (0 == i)) {
diff --git a/sonoff/xsns_05_ds18x20_legacy.ino b/sonoff/xsns_05_ds18x20_legacy.ino
index 2b157cfb7..9ecdcbff5 100644
--- a/sonoff/xsns_05_ds18x20_legacy.ino
+++ b/sonoff/xsns_05_ds18x20_legacy.ino
@@ -178,12 +178,12 @@ void Ds18x20Show(bool json)
 
       if (json) {
         if (!dsxflg) {
-          snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"DS18x20\":{"), mqtt_data);
+          ResponseAppend_P(PSTR(",\"DS18x20\":{"));
           stemp[0] = '\0';
         }
         dsxflg++;
-        snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s%s\"DS%d\":{\"" D_JSON_TYPE "\":\"%s\",\"" D_JSON_ADDRESS "\":\"%s\",\"" D_JSON_TEMPERATURE "\":%s}"),
-          mqtt_data, stemp, i +1, ds18x20_types, Ds18x20Addresses(i).c_str(), temperature);
+        ResponseAppend_P(PSTR("%s\"DS%d\":{\"" D_JSON_TYPE "\":\"%s\",\"" D_JSON_ADDRESS "\":\"%s\",\"" D_JSON_TEMPERATURE "\":%s}"),
+          stemp, i +1, ds18x20_types, Ds18x20Addresses(i).c_str(), temperature);
         strlcpy(stemp, ",", sizeof(stemp));
 #ifdef USE_DOMOTICZ
         if ((0 == tele_period) && (1 == dsxflg)) {
@@ -205,7 +205,7 @@ void Ds18x20Show(bool json)
   }
   if (json) {
     if (dsxflg) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s}"), mqtt_data);
+      ResponseAppend_P(PSTR("}"));
     }
   }
   Ds18x20Search();      // Check for changes in sensors number
diff --git a/sonoff/xsns_06_dht.ino b/sonoff/xsns_06_dht.ino
index 016f012f0..00bbf7f15 100644
--- a/sonoff/xsns_06_dht.ino
+++ b/sonoff/xsns_06_dht.ino
@@ -213,7 +213,7 @@ void DhtShow(bool json)
     dtostrfd(Dht[i].h, Settings.flag2.humidity_resolution, humidity);
 
     if (json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), JSON_SNS_TEMPHUM, mqtt_data, Dht[i].stype, temperature, humidity);
+      ResponseAppend_P(JSON_SNS_TEMPHUM, Dht[i].stype, temperature, humidity);
 #ifdef USE_DOMOTICZ
       if ((0 == tele_period) && (0 == i)) {
         DomoticzTempHumSensor(temperature, humidity);
diff --git a/sonoff/xsns_07_sht1x.ino b/sonoff/xsns_07_sht1x.ino
index 0967560b1..12d7f4e79 100644
--- a/sonoff/xsns_07_sht1x.ino
+++ b/sonoff/xsns_07_sht1x.ino
@@ -194,7 +194,7 @@ void ShtShow(bool json)
     dtostrfd(sht_humidity, Settings.flag2.humidity_resolution, humidity);
 
     if (json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), JSON_SNS_TEMPHUM, mqtt_data, sht_types, temperature, humidity);
+      ResponseAppend_P(JSON_SNS_TEMPHUM, sht_types, temperature, humidity);
 #ifdef USE_DOMOTICZ
       if (0 == tele_period) {
         DomoticzTempHumSensor(temperature, humidity);
diff --git a/sonoff/xsns_08_htu21.ino b/sonoff/xsns_08_htu21.ino
index 1ef208d61..c12a068c9 100644
--- a/sonoff/xsns_08_htu21.ino
+++ b/sonoff/xsns_08_htu21.ino
@@ -254,7 +254,7 @@ void HtuShow(bool json)
     dtostrfd(htu_humidity, Settings.flag2.humidity_resolution, humidity);
 
     if (json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), JSON_SNS_TEMPHUM, mqtt_data, htu_types, temperature, humidity);
+      ResponseAppend_P(JSON_SNS_TEMPHUM, htu_types, temperature, humidity);
 #ifdef USE_DOMOTICZ
       if (0 == tele_period) {
         DomoticzTempHumSensor(temperature, humidity);
diff --git a/sonoff/xsns_09_bmp.ino b/sonoff/xsns_09_bmp.ino
index 22b0cd365..cc738f977 100755
--- a/sonoff/xsns_09_bmp.ino
+++ b/sonoff/xsns_09_bmp.ino
@@ -566,8 +566,7 @@ void BmpShow(bool json)
         char json_gas[40];
         snprintf_P(json_gas, sizeof(json_gas), PSTR(",\"" D_JSON_GAS "\":%s"), gas_resistance);
 
-        snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_TEMPERATURE "\":%s%s,\"" D_JSON_PRESSURE "\":%s%s%s}"),
-          mqtt_data,
+        ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_TEMPERATURE "\":%s%s,\"" D_JSON_PRESSURE "\":%s%s%s}"),
           name,
           temperature,
           (bmp_sensors[bmp_idx].bmp_model >= 2) ? json_humidity : "",
@@ -575,8 +574,8 @@ void BmpShow(bool json)
           (Settings.altitude != 0) ? json_sealevel : "",
           (bmp_sensors[bmp_idx].bmp_model >= 3) ? json_gas : "");
 #else
-        snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_TEMPERATURE "\":%s%s,\"" D_JSON_PRESSURE "\":%s%s}"),
-          mqtt_data, name, temperature, (bmp_sensors[bmp_idx].bmp_model >= 2) ? json_humidity : "", pressure, (Settings.altitude != 0) ? json_sealevel : "");
+        ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_TEMPERATURE "\":%s%s,\"" D_JSON_PRESSURE "\":%s%s}"),
+          name, temperature, (bmp_sensors[bmp_idx].bmp_model >= 2) ? json_humidity : "", pressure, (Settings.altitude != 0) ? json_sealevel : "");
 #endif  // USE_BME680
 
 #ifdef USE_DOMOTICZ
diff --git a/sonoff/xsns_10_bh1750.ino b/sonoff/xsns_10_bh1750.ino
index d4ffa3a10..5398422b7 100644
--- a/sonoff/xsns_10_bh1750.ino
+++ b/sonoff/xsns_10_bh1750.ino
@@ -92,7 +92,7 @@ void Bh1750Show(bool json)
 {
   if (bh1750_valid) {
     if (json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_ILLUMINANCE "\":%d}"), mqtt_data, bh1750_types, bh1750_illuminance);
+      ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_ILLUMINANCE "\":%d}"), bh1750_types, bh1750_illuminance);
 #ifdef USE_DOMOTICZ
       if (0 == tele_period) {
         DomoticzSensor(DZ_ILLUMINANCE, bh1750_illuminance);
diff --git a/sonoff/xsns_11_veml6070.ino b/sonoff/xsns_11_veml6070.ino
index 2222cc335..b6f50d05d 100644
--- a/sonoff/xsns_11_veml6070.ino
+++ b/sonoff/xsns_11_veml6070.ino
@@ -277,11 +277,11 @@ void Veml6070Show(bool json)
     dtostrfd(uvpower, 3, str_uvpower);
     if (json) {
 #ifdef USE_VEML6070_SHOW_RAW
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_UV_LEVEL "\":%s,\"" D_JSON_UV_INDEX "\":%s,\"" D_JSON_UV_INDEX_TEXT "\":\"%s\",\"" D_JSON_UV_POWER "\":%s}"),
-        mqtt_data, veml6070_name, str_uvlevel, str_uvrisk, str_uvrisk_text, str_uvpower);
+      ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_UV_LEVEL "\":%s,\"" D_JSON_UV_INDEX "\":%s,\"" D_JSON_UV_INDEX_TEXT "\":\"%s\",\"" D_JSON_UV_POWER "\":%s}"),
+        veml6070_name, str_uvlevel, str_uvrisk, str_uvrisk_text, str_uvpower);
 #else
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_UV_INDEX "\":%s,\"" D_JSON_UV_INDEX_TEXT "\":\"%s\",\"" D_JSON_UV_POWER "\":%s}"),
-        mqtt_data, veml6070_name, str_uvrisk, str_uvrisk_text, str_uvpower);
+      ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_UV_INDEX "\":%s,\"" D_JSON_UV_INDEX_TEXT "\":\"%s\",\"" D_JSON_UV_POWER "\":%s}"),
+        veml6070_name, str_uvrisk, str_uvrisk_text, str_uvpower);
 #endif  // USE_VEML6070_SHOW_RAW
 #ifdef USE_DOMOTICZ
     if (0 == tele_period) { DomoticzSensor(DZ_ILLUMINANCE, uvlevel); }
diff --git a/sonoff/xsns_12_ads1115.ino b/sonoff/xsns_12_ads1115.ino
index 7c674debe..d40b72849 100644
--- a/sonoff/xsns_12_ads1115.ino
+++ b/sonoff/xsns_12_ads1115.ino
@@ -188,13 +188,13 @@ void Ads1115GetValues(uint8_t address)
 
 void Ads1115toJSON(char *comma_j)
 {
-  snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s%s{"), mqtt_data,comma_j);
+  ResponseAppend_P(PSTR("%s{"), comma_j);
   char *comma = (char*)"";
   for (uint8_t i = 0; i < 4; i++) {
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s%s\"A%d\":%d"), mqtt_data, comma, i, ads1115_values[i]);
+    ResponseAppend_P(PSTR("%s\"A%d\":%d"), comma, i, ads1115_values[i]);
     comma = (char*)",";
   }
-  snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s}"), mqtt_data);
+  ResponseAppend_P(PSTR("}"));
 }
 
 void Ads1115toString(uint8_t address)
@@ -212,7 +212,7 @@ void Ads1115Show(bool json)
   if (!ads1115_type) { return; }
 
   if (json) {
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"ADS1115\":["), mqtt_data);
+    ResponseAppend_P(PSTR(",\"ADS1115\":["));
   }
 
   char *comma = (char*)"";
@@ -234,7 +234,7 @@ void Ads1115Show(bool json)
   }
 
   if (json) {
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s]"), mqtt_data);
+    ResponseAppend_P(PSTR("]"));
   }
 }
 
diff --git a/sonoff/xsns_12_ads1115_i2cdev.ino b/sonoff/xsns_12_ads1115_i2cdev.ino
index 855658647..eb5643c3e 100644
--- a/sonoff/xsns_12_ads1115_i2cdev.ino
+++ b/sonoff/xsns_12_ads1115_i2cdev.ino
@@ -99,7 +99,6 @@ void Ads1115Detect(void)
 void Ads1115Show(bool json)
 {
   if (ads1115_type) {
-    char stemp[10];
 
     uint8_t dsxflg = 0;
     for (uint8_t i = 0; i < 4; i++) {
@@ -107,12 +106,10 @@ void Ads1115Show(bool json)
 
       if (json) {
         if (!dsxflg  ) {
-          snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"ADS1115\":{"), mqtt_data);
-          stemp[0] = '\0';
+          ResponseAppend_P(PSTR(",\"ADS1115\":{"));
         }
+        ResponseAppend_P(PSTR("%s\"A%d\":%d"), (dsxflg) ? "," : "", i, adc_value);
         dsxflg++;
-        snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s%s\"A%d\":%d"), mqtt_data, stemp, i, adc_value);
-        strlcpy(stemp, ",", sizeof(stemp));
 #ifdef USE_WEBSERVER
       } else {
         WSContentSend_PD(HTTP_SNS_ANALOG, "ADS1115", i, adc_value);
@@ -121,7 +118,7 @@ void Ads1115Show(bool json)
     }
     if (json) {
       if (dsxflg) {
-        snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s}"), mqtt_data);
+        ResponseAppend_P(PSTR("}"));
       }
     }
   }
diff --git a/sonoff/xsns_13_ina219.ino b/sonoff/xsns_13_ina219.ino
index fa6327f70..0dd7e5398 100644
--- a/sonoff/xsns_13_ina219.ino
+++ b/sonoff/xsns_13_ina219.ino
@@ -183,7 +183,7 @@ bool Ina219CommandSensor(void)
     Settings.ina219_mode = XdrvMailbox.payload;
     restart_flag = 2;
   }
-  snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SENSOR_INDEX_NVALUE, XSNS_13, Settings.ina219_mode);
+  Response_P(S_JSON_SENSOR_INDEX_NVALUE, XSNS_13, Settings.ina219_mode);
 
   return serviced;
 }
@@ -240,8 +240,8 @@ void Ina219Show(bool json)
     dtostrfd(ina219_current, Settings.flag2.current_resolution, current);
 
     if (json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_VOLTAGE "\":%s,\"" D_JSON_CURRENT "\":%s,\"" D_JSON_POWERUSAGE "\":%s}"),
-        mqtt_data, ina219_types, voltage, current, power);
+      ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_VOLTAGE "\":%s,\"" D_JSON_CURRENT "\":%s,\"" D_JSON_POWERUSAGE "\":%s}"),
+        ina219_types, voltage, current, power);
 #ifdef USE_DOMOTICZ
       if (0 == tele_period) {
         DomoticzSensor(DZ_VOLTAGE, voltage);
diff --git a/sonoff/xsns_14_sht3x.ino b/sonoff/xsns_14_sht3x.ino
index e7aa63007..bdaa43e1a 100755
--- a/sonoff/xsns_14_sht3x.ino
+++ b/sonoff/xsns_14_sht3x.ino
@@ -110,7 +110,7 @@ void Sht3xShow(bool json)
         snprintf_P(types, sizeof(types), PSTR("%s-0x%02X"), sht3x_sensors[i].types, sht3x_sensors[i].address);  // "SHT3X-0xXX"
 
         if (json) {
-          snprintf_P(mqtt_data, sizeof(mqtt_data), JSON_SNS_TEMPHUM, mqtt_data, types, temperature, humidity);
+          ResponseAppend_P(JSON_SNS_TEMPHUM, types, temperature, humidity);
 #ifdef USE_DOMOTICZ
           if ((0 == tele_period) && (0 == i)) {  // We want the same first sensor to report to Domoticz in case a read is missed
             DomoticzTempHumSensor(temperature, humidity);
diff --git a/sonoff/xsns_15_mhz19.ino b/sonoff/xsns_15_mhz19.ino
index 058336f39..00f272a55 100644
--- a/sonoff/xsns_15_mhz19.ino
+++ b/sonoff/xsns_15_mhz19.ino
@@ -276,42 +276,42 @@ bool MhzCommandSensor(void)
     case 0:
       Settings.SensorBits1.mhz19b_abc_disable = true;
       MhzSendCmd(MHZ_CMND_ABCDISABLE);
-      snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, ABC_DISABLED);
+      Response_P(S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, ABC_DISABLED);
       break;
     case 1:
       Settings.SensorBits1.mhz19b_abc_disable = false;
       MhzSendCmd(MHZ_CMND_ABCENABLE);
-      snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, ABC_ENABLED);
+      Response_P(S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, ABC_ENABLED);
       break;
     case 2:
       MhzSendCmd(MHZ_CMND_ZEROPOINT);
-      snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, D_JSON_ZERO_POINT_CALIBRATION);
+      Response_P(S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, D_JSON_ZERO_POINT_CALIBRATION);
       break;
     case 9:
       MhzSendCmd(MHZ_CMND_RESET);
-      snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, D_JSON_RESET);
+      Response_P(S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, D_JSON_RESET);
       break;
     case 1000:
       MhzSendCmd(MHZ_CMND_RANGE_1000);
-      snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, D_JSON_RANGE_1000);
+      Response_P(S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, D_JSON_RANGE_1000);
       break;
     case 2000:
       MhzSendCmd(MHZ_CMND_RANGE_2000);
-      snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, D_JSON_RANGE_2000);
+      Response_P(S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, D_JSON_RANGE_2000);
       break;
     case 3000:
       MhzSendCmd(MHZ_CMND_RANGE_3000);
-      snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, D_JSON_RANGE_3000);
+      Response_P(S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, D_JSON_RANGE_3000);
       break;
     case 5000:
       MhzSendCmd(MHZ_CMND_RANGE_5000);
-      snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, D_JSON_RANGE_5000);
+      Response_P(S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, D_JSON_RANGE_5000);
       break;
     default:
       if (!Settings.SensorBits1.mhz19b_abc_disable) {
-        snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, ABC_ENABLED);
+        Response_P(S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, ABC_ENABLED);
       } else {
-        snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, ABC_DISABLED);
+        Response_P(S_JSON_SENSOR_INDEX_SVALUE, XSNS_15, ABC_DISABLED);
       }
   }
 
@@ -342,7 +342,7 @@ void MhzShow(bool json)
   GetTextIndexed(model, sizeof(model), mhz_type -1, kMhzModels);
 
   if (json) {
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_MODEL "\":\"%s\",\"" D_JSON_CO2 "\":%d,\"" D_JSON_TEMPERATURE "\":%s}"), mqtt_data, types, model, mhz_last_ppm, temperature);
+    ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_MODEL "\":\"%s\",\"" D_JSON_CO2 "\":%d,\"" D_JSON_TEMPERATURE "\":%s}"), types, model, mhz_last_ppm, temperature);
 #ifdef USE_DOMOTICZ
     if (0 == tele_period) {
       DomoticzSensor(DZ_AIRQUALITY, mhz_last_ppm);
diff --git a/sonoff/xsns_16_tsl2561.ino b/sonoff/xsns_16_tsl2561.ino
index 74f9fb0fb..af1d60d54 100644
--- a/sonoff/xsns_16_tsl2561.ino
+++ b/sonoff/xsns_16_tsl2561.ino
@@ -102,8 +102,8 @@ void Tsl2561Show(bool json)
 {
   if (tsl2561_valid) {
     if (json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"TSL2561\":{\"" D_JSON_ILLUMINANCE "\":%u.%03u}"),
-        mqtt_data, tsl2561_milliLux / 1000, tsl2561_milliLux % 1000);
+      ResponseAppend_P(PSTR(",\"TSL2561\":{\"" D_JSON_ILLUMINANCE "\":%u.%03u}"),
+        tsl2561_milliLux / 1000, tsl2561_milliLux % 1000);
 #ifdef USE_DOMOTICZ
       if (0 == tele_period) { DomoticzSensor(DZ_ILLUMINANCE, (tsl2561_milliLux + 500) / 1000); }
 #endif  // USE_DOMOTICZ
diff --git a/sonoff/xsns_17_senseair.ino b/sonoff/xsns_17_senseair.ino
index b5772a4d1..d11195b50 100644
--- a/sonoff/xsns_17_senseair.ino
+++ b/sonoff/xsns_17_senseair.ino
@@ -149,11 +149,11 @@ void SenseairShow(bool json)
   GetTextIndexed(senseair_types, sizeof(senseair_types), senseair_type -1, kSenseairTypes);
 
   if (json) {
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_CO2 "\":%d"), mqtt_data, senseair_types, senseair_co2);
+    ResponseAppend_P(PSTR("%s,\"%s\":{\"" D_JSON_CO2 "\":%d"), senseair_types, senseair_co2);
     if (senseair_type != 2) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s"), mqtt_data, temperature, humidity);
+      ResponseAppend_P(PSTR("%s,\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s"), temperature, humidity);
     }
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s}"), mqtt_data);
+    ResponseAppend_P(PSTR("}"));
 #ifdef USE_DOMOTICZ
     if (0 == tele_period) DomoticzSensor(DZ_AIRQUALITY, senseair_co2);
 #endif  // USE_DOMOTICZ
diff --git a/sonoff/xsns_18_pms5003.ino b/sonoff/xsns_18_pms5003.ino
index 6f9c97711..e77eb0271 100644
--- a/sonoff/xsns_18_pms5003.ino
+++ b/sonoff/xsns_18_pms5003.ino
@@ -132,7 +132,7 @@ void PmsShow(bool json)
 {
   if (pms_valid) {
     if (json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"PMS5003\":{\"CF1\":%d,\"CF2.5\":%d,\"CF10\":%d,\"PM1\":%d,\"PM2.5\":%d,\"PM10\":%d,\"PB0.3\":%d,\"PB0.5\":%d,\"PB1\":%d,\"PB2.5\":%d,\"PB5\":%d,\"PB10\":%d}"), mqtt_data,
+      ResponseAppend_P(PSTR(",\"PMS5003\":{\"CF1\":%d,\"CF2.5\":%d,\"CF10\":%d,\"PM1\":%d,\"PM2.5\":%d,\"PM10\":%d,\"PB0.3\":%d,\"PB0.5\":%d,\"PB1\":%d,\"PB2.5\":%d,\"PB5\":%d,\"PB10\":%d}"),
         pms_data.pm10_standard, pms_data.pm25_standard, pms_data.pm100_standard,
         pms_data.pm10_env, pms_data.pm25_env, pms_data.pm100_env,
         pms_data.particles_03um, pms_data.particles_05um, pms_data.particles_10um, pms_data.particles_25um, pms_data.particles_50um, pms_data.particles_100um);
diff --git a/sonoff/xsns_19_mgs.ino b/sonoff/xsns_19_mgs.ino
index 942664b96..30b979eaa 100644
--- a/sonoff/xsns_19_mgs.ino
+++ b/sonoff/xsns_19_mgs.ino
@@ -64,14 +64,14 @@ void MGSShow(bool json)
 {
   char buffer[33];
   if (json) {
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"MGS\":{\"NH3\":%s"), mqtt_data, measure_gas(NH3, buffer));
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"CO\":%s"), mqtt_data, measure_gas(CO, buffer));
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"NO2\":%s"), mqtt_data, measure_gas(NO2, buffer));
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"C3H8\":%s"), mqtt_data, measure_gas(C3H8, buffer));
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"C4H10\":%s"), mqtt_data, measure_gas(C4H10, buffer));
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"CH4\":%s"), mqtt_data, measure_gas(GAS_CH4, buffer));
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"H2\":%s"), mqtt_data, measure_gas(H2, buffer));
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"C2H5OH\":%s}"), mqtt_data, measure_gas(C2H5OH, buffer));
+    ResponseAppend_P(PSTR(",\"MGS\":{\"NH3\":%s"), measure_gas(NH3, buffer));
+    ResponseAppend_P(PSTR(",\"CO\":%s"), measure_gas(CO, buffer));
+    ResponseAppend_P(PSTR(",\"NO2\":%s"), measure_gas(NO2, buffer));
+    ResponseAppend_P(PSTR(",\"C3H8\":%s"), measure_gas(C3H8, buffer));
+    ResponseAppend_P(PSTR(",\"C4H10\":%s"), measure_gas(C4H10, buffer));
+    ResponseAppend_P(PSTR(",\"CH4\":%s"), measure_gas(GAS_CH4, buffer));
+    ResponseAppend_P(PSTR(",\"H2\":%s"), measure_gas(H2, buffer));
+    ResponseAppend_P(PSTR(",\"C2H5OH\":%s}"), measure_gas(C2H5OH, buffer));
 #ifdef USE_WEBSERVER
   } else {
     WSContentSend_PD(HTTP_MGS_GAS, "NH3", measure_gas(NH3, buffer));
diff --git a/sonoff/xsns_20_novasds.ino b/sonoff/xsns_20_novasds.ino
index 702d3d8fe..25f73c2df 100644
--- a/sonoff/xsns_20_novasds.ino
+++ b/sonoff/xsns_20_novasds.ino
@@ -195,7 +195,7 @@ void NovaSdsShow(bool json)
     char pm2_5[33];
     dtostrfd(pm2_5f, 1, pm2_5);
     if (json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"SDS0X1\":{\"PM2.5\":%s,\"PM10\":%s}"), mqtt_data, pm2_5, pm10);
+      ResponseAppend_P(PSTR(",\"SDS0X1\":{\"PM2.5\":%s,\"PM10\":%s}"), pm2_5, pm10);
 #ifdef USE_DOMOTICZ
       if (0 == tele_period) {
         DomoticzSensor(DZ_VOLTAGE, pm2_5);  // PM2.5
diff --git a/sonoff/xsns_21_sgp30.ino b/sonoff/xsns_21_sgp30.ino
index a544e4472..d8241f1d6 100644
--- a/sonoff/xsns_21_sgp30.ino
+++ b/sonoff/xsns_21_sgp30.ino
@@ -71,7 +71,7 @@ void Sgp30Show(bool json)
 {
   if (sgp30_ready) {
     if (json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"SGP30\":{\"" D_JSON_ECO2 "\":%d,\"" D_JSON_TVOC "\":%d}"), mqtt_data, sgp.eCO2, sgp.TVOC);
+      ResponseAppend_P(PSTR(",\"SGP30\":{\"" D_JSON_ECO2 "\":%d,\"" D_JSON_TVOC "\":%d}"), sgp.eCO2, sgp.TVOC);
 #ifdef USE_DOMOTICZ
       if (0 == tele_period) DomoticzSensor(DZ_AIRQUALITY, sgp.eCO2);
 #endif  // USE_DOMOTICZ
diff --git a/sonoff/xsns_22_sr04.ino b/sonoff/xsns_22_sr04.ino
index 3c8a933bf..f30ff11f7 100644
--- a/sonoff/xsns_22_sr04.ino
+++ b/sonoff/xsns_22_sr04.ino
@@ -57,7 +57,7 @@ void Sr04Show(bool json)
     dtostrfd(distance, 3, distance_chr);
 
     if(json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"SR04\":{\"" D_JSON_DISTANCE "\":%s}"), mqtt_data, distance_chr);
+      ResponseAppend_P(PSTR(",\"SR04\":{\"" D_JSON_DISTANCE "\":%s}"), distance_chr);
 #ifdef USE_DOMOTICZ
       if (0 == tele_period) {
         DomoticzSensor(DZ_COUNT, distance_chr);  // Send distance as Domoticz Counter value
diff --git a/sonoff/xsns_23_sdm120.ino b/sonoff/xsns_23_sdm120.ino
index c77ca1875..8f0b6b74f 100644
--- a/sonoff/xsns_23_sdm120.ino
+++ b/sonoff/xsns_23_sdm120.ino
@@ -314,11 +314,11 @@ void SDM120Show(bool json)
 #endif // USE_SDM220
   if (json) {
 #ifdef USE_SDM220
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"" D_RSLT_ENERGY "\":{\"" D_JSON_TOTAL "\":%s,\"" D_JSON_ACTIVE_POWERUSAGE "\":%s,\"" D_JSON_APPARENT_POWERUSAGE "\":%s,\"" D_JSON_REACTIVE_POWERUSAGE "\":%s,\"" D_JSON_FREQUENCY "\":%s,\"" D_JSON_POWERFACTOR "\":%s,\"" D_JSON_VOLTAGE "\":%s,\"" D_JSON_CURRENT  "\":%s,\"" D_JSON_PHASE_ANGLE "\":%s,\"" D_JSON_IMPORT_ACTIVE "\":%s,\"" D_JSON_EXPORT_ACTIVE "\":%s,\"" D_JSON_IMPORT_REACTIVE "\":%s,\"" D_JSON_EXPORT_REACTIVE "\":%s,\"" D_JSON_TOTAL_REACTIVE "\":%s}"),
-      mqtt_data, energy_total, active_power, apparent_power, reactive_power, frequency, power_factor, voltage, current, phase_angle, import_active, export_active, import_reactive, export_reactive, total_reactive);
+    ResponseAppend_P(PSTR(",\"" D_RSLT_ENERGY "\":{\"" D_JSON_TOTAL "\":%s,\"" D_JSON_ACTIVE_POWERUSAGE "\":%s,\"" D_JSON_APPARENT_POWERUSAGE "\":%s,\"" D_JSON_REACTIVE_POWERUSAGE "\":%s,\"" D_JSON_FREQUENCY "\":%s,\"" D_JSON_POWERFACTOR "\":%s,\"" D_JSON_VOLTAGE "\":%s,\"" D_JSON_CURRENT  "\":%s,\"" D_JSON_PHASE_ANGLE "\":%s,\"" D_JSON_IMPORT_ACTIVE "\":%s,\"" D_JSON_EXPORT_ACTIVE "\":%s,\"" D_JSON_IMPORT_REACTIVE "\":%s,\"" D_JSON_EXPORT_REACTIVE "\":%s,\"" D_JSON_TOTAL_REACTIVE "\":%s}"),
+      energy_total, active_power, apparent_power, reactive_power, frequency, power_factor, voltage, current, phase_angle, import_active, export_active, import_reactive, export_reactive, total_reactive);
 #else
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"" D_RSLT_ENERGY "\":{\"" D_JSON_TOTAL "\":%s,\"" D_JSON_ACTIVE_POWERUSAGE "\":%s,\"" D_JSON_APPARENT_POWERUSAGE "\":%s,\"" D_JSON_REACTIVE_POWERUSAGE "\":%s,\"" D_JSON_FREQUENCY "\":%s,\"" D_JSON_POWERFACTOR "\":%s,\"" D_JSON_VOLTAGE "\":%s,\"" D_JSON_CURRENT "\":%s}"),
-      mqtt_data, energy_total, active_power, apparent_power, reactive_power, frequency, power_factor, voltage, current);
+    ResponseAppend_P(PSTR(",\"" D_RSLT_ENERGY "\":{\"" D_JSON_TOTAL "\":%s,\"" D_JSON_ACTIVE_POWERUSAGE "\":%s,\"" D_JSON_APPARENT_POWERUSAGE "\":%s,\"" D_JSON_REACTIVE_POWERUSAGE "\":%s,\"" D_JSON_FREQUENCY "\":%s,\"" D_JSON_POWERFACTOR "\":%s,\"" D_JSON_VOLTAGE "\":%s,\"" D_JSON_CURRENT "\":%s}"),
+      energy_total, active_power, apparent_power, reactive_power, frequency, power_factor, voltage, current);
 #endif // USE_SDM220
 #ifdef USE_DOMOTICZ
     if (0 == tele_period) {
diff --git a/sonoff/xsns_24_si1145.ino b/sonoff/xsns_24_si1145.ino
index 56bce1018..2a1c26cd5 100644
--- a/sonoff/xsns_24_si1145.ino
+++ b/sonoff/xsns_24_si1145.ino
@@ -329,8 +329,8 @@ void Si1145Show(bool json)
     uint16_t infrared = Si1145ReadIR();
     uint16_t uvindex = Si1145ReadUV();
     if (json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"SI1145\":{\"" D_JSON_ILLUMINANCE "\":%d,\"" D_JSON_INFRARED "\":%d,\"" D_JSON_UV_INDEX "\":%d.%d}"),
-        mqtt_data, visible, infrared, uvindex /100, uvindex %100);
+      ResponseAppend_P(PSTR(",\"SI1145\":{\"" D_JSON_ILLUMINANCE "\":%d,\"" D_JSON_INFRARED "\":%d,\"" D_JSON_UV_INDEX "\":%d.%d}"),
+        visible, infrared, uvindex /100, uvindex %100);
 #ifdef USE_DOMOTICZ
       if (0 == tele_period) DomoticzSensor(DZ_ILLUMINANCE, visible);
 #endif  // USE_DOMOTICZ
diff --git a/sonoff/xsns_25_sdm630.ino b/sonoff/xsns_25_sdm630.ino
index 013964915..c71009ce4 100644
--- a/sonoff/xsns_25_sdm630.ino
+++ b/sonoff/xsns_25_sdm630.ino
@@ -302,10 +302,10 @@ void SDM630Show(bool json)
   dtostrfd(sdm630_energy_total, Settings.flag2.energy_resolution, energy_total);
 
   if (json) {
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"" D_RSLT_ENERGY "\":{\"" D_JSON_TOTAL "\":%s,\""
+    ResponseAppend_P(PSTR(",\"" D_RSLT_ENERGY "\":{\"" D_JSON_TOTAL "\":%s,\""
       D_JSON_ACTIVE_POWERUSAGE "\":[%s,%s,%s],\"" D_JSON_REACTIVE_POWERUSAGE "\":[%s,%s,%s],\""
       D_JSON_POWERFACTOR "\":[%s,%s,%s],\"" D_JSON_VOLTAGE "\":[%s,%s,%s],\"" D_JSON_CURRENT "\":[%s,%s,%s]}"),
-      mqtt_data, energy_total, active_power_l1, active_power_l2, active_power_l3,
+      energy_total, active_power_l1, active_power_l2, active_power_l3,
       reactive_power_l1, reactive_power_l2, reactive_power_l3,
       power_factor_l1, power_factor_l2, power_factor_l3,
       voltage_l1, voltage_l2, voltage_l3,
diff --git a/sonoff/xsns_26_lm75ad.ino b/sonoff/xsns_26_lm75ad.ino
index b7b92fca7..88769b3aa 100644
--- a/sonoff/xsns_26_lm75ad.ino
+++ b/sonoff/xsns_26_lm75ad.ino
@@ -85,7 +85,7 @@ void LM75ADShow(bool json)
     dtostrfd(t, Settings.flag2.temperature_resolution, temperature);
 
     if (json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"LM75AD\":{\"" D_JSON_TEMPERATURE "\":%s}"), mqtt_data, temperature);
+      ResponseAppend_P(PSTR(",\"LM75AD\":{\"" D_JSON_TEMPERATURE "\":%s}"), temperature);
 #ifdef USE_DOMOTICZ
       if (0 == tele_period) DomoticzSensor(DZ_TEMP, temperature);
 #endif  // USE_DOMOTICZ
diff --git a/sonoff/xsns_27_apds9960.ino b/sonoff/xsns_27_apds9960.ino
index 5be8b0e5b..7594a5322 100644
--- a/sonoff/xsns_27_apds9960.ino
+++ b/sonoff/xsns_27_apds9960.ino
@@ -1874,7 +1874,7 @@ void APDS9960_loop(void)
   if (recovery_loop_counter == 1 && APDS9960_overload){  //restart sensor just before the end of recovery from long press
     enableGestureSensor();
     APDS9960_overload = false;
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("{\"Gesture\":\"On\"}"));
+    Response_P(PSTR("{\"Gesture\":\"On\"}"));
     MqttPublishPrefixTopic_P(RESULT_OR_TELE, mqtt_data); // only after the long break we report, that we are online again
     gesture_mode = 1;
   }
@@ -1887,7 +1887,7 @@ void APDS9960_loop(void)
         {
         disableGestureSensor();
         recovery_loop_counter = APDS9960_LONG_RECOVERY;  // long pause after overload/long press - number of stateloops
-        snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("{\"Gesture\":\"Off\"}"));
+        Response_P(PSTR("{\"Gesture\":\"Off\"}"));
         MqttPublishPrefixTopic_P(RESULT_OR_TELE, mqtt_data);
         gesture_mode = 0;
         }
@@ -1959,8 +1959,8 @@ void APDS9960_show(bool json)
     sprintf (cct_chr, "%u", color_data.cct);
 
     if (json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"Red\":%s,\"Green\":%s,\"Blue\":%s,\"Ambient\":%s,\"CCT\":%s,\"Proximity\":%s}"),
-        mqtt_data, APDS9960stype, red_chr, green_chr, blue_chr, ambient_chr, cct_chr, prox_chr);
+      ResponseAppend_P(PSTR(",\"%s\":{\"Red\":%s,\"Green\":%s,\"Blue\":%s,\"Ambient\":%s,\"CCT\":%s,\"Proximity\":%s}"),
+        APDS9960stype, red_chr, green_chr, blue_chr, ambient_chr, cct_chr, prox_chr);
 #ifdef USE_WEBSERVER
     } else {
       WSContentSend_PD(HTTP_APDS_9960_SNS, red_chr, green_chr, blue_chr, ambient_chr, cct_chr, prox_chr );
@@ -1969,7 +1969,7 @@ void APDS9960_show(bool json)
   }
   else {
     if (json && (currentGesture[0] != '\0' )) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"%s\":1}"), mqtt_data, APDS9960stype, currentGesture);
+      ResponseAppend_P(PSTR(",\"%s\":{\"%s\":1}"), APDS9960stype, currentGesture);
       currentGesture[0] = '\0';
     }
   }
@@ -2025,7 +2025,7 @@ bool APDS9960CommandSensor(void)
       }
     break;
   }
-  snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SENSOR_INDEX_SVALUE, XSNS_27, GetStateText(gesture_mode));
+  Response_P(S_JSON_SENSOR_INDEX_SVALUE, XSNS_27, GetStateText(gesture_mode));
 
   return serviced;
 }
diff --git a/sonoff/xsns_29_mcp230xx.ino b/sonoff/xsns_29_mcp230xx.ino
index 5aa4992dd..bef4e1738 100644
--- a/sonoff/xsns_29_mcp230xx.ino
+++ b/sonoff/xsns_29_mcp230xx.ino
@@ -303,9 +303,8 @@ void MCP230xx_CheckForInterrupt(void) {
                       break;
                   }
                   if (int_tele) {
-                    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("{\"" D_JSON_TIME "\":\"%s\""), GetDateAndTime(DT_LOCAL).c_str());
-                    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"MCP230XX_INT\":{\"D%i\":%i,\"MS\":%lu}"), mqtt_data, intp+(mcp230xx_port*8), ((mcp230xx_intcap >> intp) & 0x01),millis_since_last_int);
-                    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s}"), mqtt_data);
+                    Response_P(PSTR("{\"" D_JSON_TIME "\":\"%s\",\"MCP230XX_INT\":{\"D%i\":%i,\"MS\":%lu}}"),
+                      GetDateAndTime(DT_LOCAL).c_str(), intp+(mcp230xx_port*8), ((mcp230xx_intcap >> intp) & 0x01),millis_since_last_int);
                     MqttPublishPrefixTopic_P(RESULT_OR_STAT, PSTR("MCP230XX_INT"));
                   }
                   if (int_event) {
@@ -329,14 +328,14 @@ void MCP230xx_Show(bool json)
     if (json) {
       if (mcp230xx_type > 0) { // we have at least 8 pins
         uint8_t gpio = MCP230xx_readGPIO(0);
-        snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"MCP230XX\":{\"D0\":%i,\"D1\":%i,\"D2\":%i,\"D3\":%i,\"D4\":%i,\"D5\":%i,\"D6\":%i,\"D7\":%i"),
-                   mqtt_data,(gpio>>0)&1,(gpio>>1)&1,(gpio>>2)&1,(gpio>>3)&1,(gpio>>4)&1,(gpio>>5)&1,(gpio>>6)&1,(gpio>>7)&1);
+        ResponseAppend_P(PSTR(",\"MCP230XX\":{\"D0\":%i,\"D1\":%i,\"D2\":%i,\"D3\":%i,\"D4\":%i,\"D5\":%i,\"D6\":%i,\"D7\":%i"),
+                   (gpio>>0)&1,(gpio>>1)&1,(gpio>>2)&1,(gpio>>3)&1,(gpio>>4)&1,(gpio>>5)&1,(gpio>>6)&1,(gpio>>7)&1);
         if (2 == mcp230xx_type) {
           gpio = MCP230xx_readGPIO(1);
-          snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"D8\":%i,\"D9\":%i,\"D10\":%i,\"D11\":%i,\"D12\":%i,\"D13\":%i,\"D14\":%i,\"D15\":%i"),
-                     mqtt_data,(gpio>>0)&1,(gpio>>1)&1,(gpio>>2)&1,(gpio>>3)&1,(gpio>>4)&1,(gpio>>5)&1,(gpio>>6)&1,(gpio>>7)&1);
+          ResponseAppend_P(PSTR(",\"D8\":%i,\"D9\":%i,\"D10\":%i,\"D11\":%i,\"D12\":%i,\"D13\":%i,\"D14\":%i,\"D15\":%i"),
+                     (gpio>>0)&1,(gpio>>1)&1,(gpio>>2)&1,(gpio>>3)&1,(gpio>>4)&1,(gpio>>5)&1,(gpio>>6)&1,(gpio>>7)&1);
         }
-        snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s%s"),mqtt_data,"}");
+        ResponseAppend_P(PSTR("}"));
       }
     }
   }
@@ -384,9 +383,9 @@ void MCP230xx_SetOutPin(uint8_t pin,uint8_t pinstate) {
   if (interlock && (pinmo == Settings.mcp230xx_config[pin+pinadd].pinmode)) {
     char stt1[4];
     sprintf(stt1,ConvertNumTxt((portpins >> (pin+pinadd-(port*8))&1), pinmo));
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("{\"S29cmnd_D%i\":{\"COMMAND\":\"%s\",\"STATE\":\"%s\"},\"S29cmnd_D%i\":{\"STATE\":\"%s\"}}"),pin, cmnd, stt, pin+pinadd, stt1);
+    Response_P(PSTR("{\"S29cmnd_D%i\":{\"COMMAND\":\"%s\",\"STATE\":\"%s\"},\"S29cmnd_D%i\":{\"STATE\":\"%s\"}}"),pin, cmnd, stt, pin+pinadd, stt1);
   } else {
-    snprintf_P(mqtt_data, sizeof(mqtt_data), MCP230XX_CMND_RESPONSE, pin, cmnd, stt);
+    Response_P(MCP230XX_CMND_RESPONSE, pin, cmnd, stt);
   }
 }
 
@@ -420,7 +419,7 @@ void MCP230xx_Reset(uint8_t pinmode) {
   uint8_t intmode = 3;
   if ((pinmode > 1) && (pinmode < 5)) { intmode = 0; }
   sprintf(intmodetxt,IntModeTxt(intmode));
-  snprintf_P(mqtt_data, sizeof(mqtt_data), MCP230XX_SENSOR_RESPONSE,99,pinmode,pulluptxt,intmodetxt,"");
+  Response_P(MCP230XX_SENSOR_RESPONSE,99,pinmode,pulluptxt,intmodetxt,"");
 }
 
 bool MCP230xx_Command(void) {
@@ -454,11 +453,11 @@ bool MCP230xx_Command(void) {
       uint8_t intpri = atoi(subStr(sub_string, XdrvMailbox.data, ",", 2));
       if ((intpri >= 0) && (intpri <= 20)) {
         Settings.mcp230xx_int_prio = intpri;
-        snprintf_P(mqtt_data, sizeof(mqtt_data), MCP230XX_INTCFG_RESPONSE,"PRI",99,Settings.mcp230xx_int_prio);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
+        Response_P(MCP230XX_INTCFG_RESPONSE,"PRI",99,Settings.mcp230xx_int_prio);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
         return serviced;
       }
     } else { // No parameter was given for INTPRI so we return the current configured value
-      snprintf_P(mqtt_data, sizeof(mqtt_data), MCP230XX_INTCFG_RESPONSE,"PRI",99,Settings.mcp230xx_int_prio);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
+      Response_P(MCP230XX_INTCFG_RESPONSE,"PRI",99,Settings.mcp230xx_int_prio);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
       return serviced;
     }
   }
@@ -469,11 +468,11 @@ bool MCP230xx_Command(void) {
       if ((inttim >= 0) && (inttim <= 3600)) {
         Settings.mcp230xx_int_timer = inttim;
         MCP230xx_CheckForIntCounter(); // update register on whether or not we should be counting interrupts
-        snprintf_P(mqtt_data, sizeof(mqtt_data), MCP230XX_INTCFG_RESPONSE,"TIMER",99,Settings.mcp230xx_int_timer);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
+        Response_P(MCP230XX_INTCFG_RESPONSE,"TIMER",99,Settings.mcp230xx_int_timer);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
         return serviced;
       }
     } else { // No parameter was given for INTTIM so we return the current configured value
-      snprintf_P(mqtt_data, sizeof(mqtt_data), MCP230XX_INTCFG_RESPONSE,"TIMER",99,Settings.mcp230xx_int_timer);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
+      Response_P(MCP230XX_INTCFG_RESPONSE,"TIMER",99,Settings.mcp230xx_int_timer);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
       return serviced;
     }
   }
@@ -498,14 +497,14 @@ bool MCP230xx_Command(void) {
               MCP230xx_CheckForIntCounter();
               AddLog_P2(LOG_LEVEL_INFO, PSTR("*** WARNING *** - Disabled INTCNT for pin D%i"),pin);
             }
-            snprintf_P(mqtt_data, sizeof(mqtt_data), MCP230XX_INTCFG_RESPONSE,"DEF",pin,Settings.mcp230xx_config[pin].int_report_defer);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
+            Response_P(MCP230XX_INTCFG_RESPONSE,"DEF",pin,Settings.mcp230xx_config[pin].int_report_defer);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
             return serviced;
           } else {
             serviced=false;
             return serviced;
           }
         } else {
-          snprintf_P(mqtt_data, sizeof(mqtt_data), MCP230XX_INTCFG_RESPONSE,"DEF",pin,Settings.mcp230xx_config[pin].int_report_defer);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
+          Response_P(MCP230XX_INTCFG_RESPONSE,"DEF",pin,Settings.mcp230xx_config[pin].int_report_defer);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
           return serviced;
         }
       }
@@ -544,14 +543,14 @@ bool MCP230xx_Command(void) {
               AddLog_P2(LOG_LEVEL_INFO, PSTR("*** WARNING *** - INTCNT enabled for pin D%i but global INTTIMER is disabled!"),pin);
             }
             MCP230xx_CheckForIntCounter(); // update register on whether or not we should be counting interrupts
-            snprintf_P(mqtt_data, sizeof(mqtt_data), MCP230XX_INTCFG_RESPONSE,"CNT",pin,Settings.mcp230xx_config[pin].int_count_en);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
+            Response_P(MCP230XX_INTCFG_RESPONSE,"CNT",pin,Settings.mcp230xx_config[pin].int_count_en);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
             return serviced;
           } else {
             serviced=false;
             return serviced;
           }
         } else {
-          snprintf_P(mqtt_data, sizeof(mqtt_data), MCP230XX_INTCFG_RESPONSE,"CNT",pin,Settings.mcp230xx_config[pin].int_count_en);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
+          Response_P(MCP230XX_INTCFG_RESPONSE,"CNT",pin,Settings.mcp230xx_config[pin].int_count_en);  // "{\"MCP230xx_INT%s\":{\"D_%i\":%i}}";
           return serviced;
         }
       }
@@ -578,7 +577,7 @@ bool MCP230xx_Command(void) {
           uint8_t int_retain = atoi(subStr(sub_string, XdrvMailbox.data, ",", 3));
           if ((int_retain >= 0) && (int_retain <= 1)) {
             Settings.mcp230xx_config[pin].int_retain_flag=int_retain;
-            snprintf_P(mqtt_data, sizeof(mqtt_data), MCP230XX_INTCFG_RESPONSE,"INT_RETAIN",pin,Settings.mcp230xx_config[pin].int_retain_flag);
+            Response_P(MCP230XX_INTCFG_RESPONSE,"INT_RETAIN",pin,Settings.mcp230xx_config[pin].int_retain_flag);
             MCP230xx_CheckForIntRetainer();
             return serviced;
           } else {
@@ -586,7 +585,7 @@ bool MCP230xx_Command(void) {
             return serviced;
           }
         } else {
-          snprintf_P(mqtt_data, sizeof(mqtt_data), MCP230XX_INTCFG_RESPONSE,"INT_RETAIN",pin,Settings.mcp230xx_config[pin].int_retain_flag);
+          Response_P(MCP230XX_INTCFG_RESPONSE,"INT_RETAIN",pin,Settings.mcp230xx_config[pin].int_retain_flag);
           return serviced;
         }
       }
@@ -619,10 +618,10 @@ bool MCP230xx_Command(void) {
 #ifdef USE_MCP230xx_OUTPUT
       uint8_t pinmod = Settings.mcp230xx_config[pin].pinmode;
       sprintf(pinstatustxtr,ConvertNumTxt(portdata>>(pin-(port*8))&1,pinmod));
-      snprintf_P(mqtt_data, sizeof(mqtt_data), MCP230XX_SENSOR_RESPONSE,pin,pinmod,pulluptxtr,intmodetxt,pinstatustxtr);
+      Response_P(MCP230XX_SENSOR_RESPONSE,pin,pinmod,pulluptxtr,intmodetxt,pinstatustxtr);
 #else // not USE_MCP230xx_OUTPUT
       sprintf(pinstatustxtr,ConvertNumTxt(portdata>>(pin-(port*8))&1));
-      snprintf_P(mqtt_data, sizeof(mqtt_data), MCP230XX_SENSOR_RESPONSE,pin,Settings.mcp230xx_config[pin].pinmode,pulluptxtr,intmodetxt,pinstatustxtr);
+      Response_P(MCP230XX_SENSOR_RESPONSE,pin,Settings.mcp230xx_config[pin].pinmode,pulluptxtr,intmodetxt,pinstatustxtr);
 #endif //USE_MCP230xx_OUTPUT
       return serviced;
     }
@@ -682,7 +681,7 @@ bool MCP230xx_Command(void) {
 #else  // not USE_MCP230xx_OUTPUT
       sprintf(pinstatustxtc,ConvertNumTxt(portdata>>(pin-(port*8))&1));
 #endif // USE_MCP230xx_OUTPUT
-      snprintf_P(mqtt_data, sizeof(mqtt_data), MCP230XX_SENSOR_RESPONSE,pin,pinmode,pulluptxtc,intmodetxt,pinstatustxtc);
+      Response_P(MCP230XX_SENSOR_RESPONSE,pin,pinmode,pulluptxtc,intmodetxt,pinstatustxtc);
       return serviced;
     }
   } else {
@@ -730,14 +729,14 @@ void MCP230xx_OutputTelemetry(void) {
   }
   if (outputcount) {
     char stt[7];
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("{\"" D_JSON_TIME "\":\"%s\",\"MCP230_OUT\": {"), GetDateAndTime(DT_LOCAL).c_str());
+    Response_P(PSTR("{\"" D_JSON_TIME "\":\"%s\",\"MCP230_OUT\": {"), GetDateAndTime(DT_LOCAL).c_str());
     for (uint8_t pinx = 0;pinx < mcp230xx_pincount;pinx++) {
       if (Settings.mcp230xx_config[pinx].pinmode >= 5) {
         sprintf(stt,ConvertNumTxt(((gpiototal>>pinx)&1),Settings.mcp230xx_config[pinx].pinmode));
-        snprintf_P(mqtt_data,sizeof(mqtt_data), PSTR("%s\"OUT_D%i\":\"%s\","),mqtt_data,pinx,stt);
+        ResponseAppend_P(PSTR("\"OUT_D%i\":\"%s\","),pinx,stt);
       }
     }
-    snprintf_P(mqtt_data,sizeof(mqtt_data),PSTR("%s\"END\":1}}"),mqtt_data);
+    ResponseAppend_P(PSTR("\"END\":1}}"));
     MqttPublishPrefixTopic_P(TELE, PSTR(D_RSLT_SENSOR), Settings.flag.mqtt_sensor_retain);
   }
 }
@@ -745,29 +744,29 @@ void MCP230xx_OutputTelemetry(void) {
 #endif // USE_MCP230xx_OUTPUT
 
 void MCP230xx_Interrupt_Counter_Report(void) {
-  snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("{\"" D_JSON_TIME "\":\"%s\",\"MCP230_INTTIMER\": {"), GetDateAndTime(DT_LOCAL).c_str());
+  Response_P(PSTR("{\"" D_JSON_TIME "\":\"%s\",\"MCP230_INTTIMER\": {"), GetDateAndTime(DT_LOCAL).c_str());
   for (uint8_t pinx = 0;pinx < mcp230xx_pincount;pinx++) {
     if (Settings.mcp230xx_config[pinx].int_count_en) { // Counting is enabled for this pin so we add to report
-      snprintf_P(mqtt_data,sizeof(mqtt_data), PSTR("%s\"INTCNT_D%i\":%i,"),mqtt_data,pinx,mcp230xx_int_counter[pinx]);
+      ResponseAppend_P(PSTR("\"INTCNT_D%i\":%i,"),pinx,mcp230xx_int_counter[pinx]);
       mcp230xx_int_counter[pinx]=0;
     }
   }
-  snprintf_P(mqtt_data,sizeof(mqtt_data),PSTR("%s\"END\":1}}"),mqtt_data);
+  ResponseAppend_P(PSTR("\"END\":1}}"));
   MqttPublishPrefixTopic_P(TELE, PSTR(D_RSLT_SENSOR), Settings.flag.mqtt_sensor_retain);
   mcp230xx_int_sec_counter = 0;
 }
 
 void MCP230xx_Interrupt_Retain_Report(void) {
   uint16_t retainresult = 0;
-  snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("{\"" D_JSON_TIME "\":\"%s\",\"MCP_INTRETAIN\": {"), GetDateAndTime(DT_LOCAL).c_str());
+  Response_P(PSTR("{\"" D_JSON_TIME "\":\"%s\",\"MCP_INTRETAIN\": {"), GetDateAndTime(DT_LOCAL).c_str());
   for (uint8_t pinx = 0;pinx < mcp230xx_pincount;pinx++) {
     if (Settings.mcp230xx_config[pinx].int_retain_flag) {
-      snprintf_P(mqtt_data,sizeof(mqtt_data), PSTR("%s\"D%i\":%i,"),mqtt_data,pinx,mcp230xx_int_retainer[pinx]);
+      ResponseAppend_P(PSTR("\"D%i\":%i,"),pinx,mcp230xx_int_retainer[pinx]);
       retainresult |= (((mcp230xx_int_retainer[pinx])&1) << pinx);
       mcp230xx_int_retainer[pinx]=0;
     }
   }
-  snprintf_P(mqtt_data,sizeof(mqtt_data),PSTR("%s\"Value\":%u}}"),mqtt_data,retainresult);
+  ResponseAppend_P(PSTR("\"Value\":%u}}"),retainresult);
   MqttPublishPrefixTopic_P(TELE, PSTR(D_RSLT_SENSOR), Settings.flag.mqtt_sensor_retain);
 }
 
diff --git a/sonoff/xsns_30_mpr121.ino b/sonoff/xsns_30_mpr121.ino
index 10ea46078..6f23117c6 100644
--- a/sonoff/xsns_30_mpr121.ino
+++ b/sonoff/xsns_30_mpr121.ino
@@ -343,7 +343,7 @@ void Mpr121Show(struct mpr121 *pS, uint8_t function)
 
 			// Append sensor to JSON message string
 			if (FUNC_JSON_APPEND == function) {
-				snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"MPR121%c\":{"), mqtt_data, pS->id[i]);
+				ResponseAppend_P(PSTR(",\"MPR121%c\":{"), pS->id[i]);
 			}
 			// Loop through buttons
 			for (uint8_t j = 0; j < 13; j++) {
@@ -351,7 +351,7 @@ void Mpr121Show(struct mpr121 *pS, uint8_t function)
 				// Add sensor, button and state to MQTT JSON message string
 				if ((FUNC_EVERY_50_MSECOND == function)
 				    && (BITC(i, j) != BITP(i, j))) {
-					snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("{\"MPR121%c\":{\"Button%i\":%i}}"), pS->id[i], j, BITC(i, j));
+					Response_P(PSTR("{\"MPR121%c\":{\"Button%i\":%i}}"), pS->id[i], j, BITC(i, j));
 					MqttPublishPrefixTopic_P(RESULT_OR_STAT, mqtt_data);
 				}
 				// Add buttons to web string
@@ -363,7 +363,7 @@ void Mpr121Show(struct mpr121 *pS, uint8_t function)
 
 				// Append JSON message string
 				if (FUNC_JSON_APPEND == function) {
-					snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s%s\"Button%i\":%i"), mqtt_data, (j > 0 ? "," : ""), j, BITC(i, j));
+					ResponseAppend_P(PSTR("%s\"Button%i\":%i"), (j > 0 ? "," : ""), j, BITC(i, j));
 				}
 			}	// for-loop j
 
@@ -372,7 +372,7 @@ void Mpr121Show(struct mpr121 *pS, uint8_t function)
 
 			// Append JSON message string
 			if (FUNC_JSON_APPEND == function) {
-				snprintf_P(mqtt_data, sizeof(mqtt_data), "%s}", mqtt_data);
+				ResponseAppend_P(PSTR("}"));
 			}
 		}		// if->running
 	}			// for-loop i
diff --git a/sonoff/xsns_31_ccs811.ino b/sonoff/xsns_31_ccs811.ino
index 9ce63b228..2624d0b8c 100644
--- a/sonoff/xsns_31_ccs811.ino
+++ b/sonoff/xsns_31_ccs811.ino
@@ -85,7 +85,7 @@ void CCS811Show(bool json)
 {
   if (CCS811_ready) {
     if (json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"CCS811\":{\"" D_JSON_ECO2 "\":%d,\"" D_JSON_TVOC "\":%d}"), mqtt_data,eCO2,TVOC);
+      ResponseAppend_P(PSTR(",\"CCS811\":{\"" D_JSON_ECO2 "\":%d,\"" D_JSON_TVOC "\":%d}"), eCO2,TVOC);
 #ifdef USE_DOMOTICZ
       if (0 == tele_period) DomoticzSensor(DZ_AIRQUALITY, eCO2);
 #endif  // USE_DOMOTICZ
diff --git a/sonoff/xsns_32_mpu6050.ino b/sonoff/xsns_32_mpu6050.ino
index e7dddd953..6ac8763bd 100644
--- a/sonoff/xsns_32_mpu6050.ino
+++ b/sonoff/xsns_32_mpu6050.ino
@@ -205,8 +205,8 @@ void MPU_6050Show(bool json)
       snprintf_P(json_axis_gy, sizeof(json_axis_gy), PSTR(",\"" D_JSON_AXIS_GY "\":%s"), axis_gy);
       char json_axis_gz[25];
       snprintf_P(json_axis_gz, sizeof(json_axis_gz), PSTR(",\"" D_JSON_AXIS_GZ "\":%s"), axis_gz);
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_TEMPERATURE "\":%s%s%s%s%s%s%s}"),
-      mqtt_data, D_SENSOR_MPU6050, temperature, json_axis_ax, json_axis_ay, json_axis_az, json_axis_gx, json_axis_gy, json_axis_gz);
+      ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_TEMPERATURE "\":%s%s%s%s%s%s%s}"),
+        D_SENSOR_MPU6050, temperature, json_axis_ax, json_axis_ay, json_axis_az, json_axis_gx, json_axis_gy, json_axis_gz);
 #ifdef USE_DOMOTICZ
       DomoticzSensor(DZ_TEMP, temperature);
 #endif // USE_DOMOTICZ
diff --git a/sonoff/xsns_34_hx711.ino b/sonoff/xsns_34_hx711.ino
index 272e35a9e..b72ef0a9f 100644
--- a/sonoff/xsns_34_hx711.ino
+++ b/sonoff/xsns_34_hx711.ino
@@ -128,7 +128,7 @@ void HxCalibrationStateTextJson(uint8_t msg_id)
   char cal_text[30];
 
   hx_calibrate_msg = msg_id;
-  snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SENSOR_INDEX_SVALUE, XSNS_34, GetTextIndexed(cal_text, sizeof(cal_text), hx_calibrate_msg, kHxCalibrationStates));
+  Response_P(S_JSON_SENSOR_INDEX_SVALUE, XSNS_34, GetTextIndexed(cal_text, sizeof(cal_text), hx_calibrate_msg, kHxCalibrationStates));
 
   if (msg_id < 3) { MqttPublishPrefixTopic_P(RESULT_OR_STAT, PSTR("Sensor34")); }
 }
@@ -162,7 +162,7 @@ bool HxCommand(void)
   switch (XdrvMailbox.payload) {
     case 1:  // Reset scale
       HxReset();
-      snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SENSOR_INDEX_SVALUE, XSNS_34, "Reset");
+      Response_P(S_JSON_SENSOR_INDEX_SVALUE, XSNS_34, "Reset");
       break;
     case 2:  // Calibrate
       if (strstr(XdrvMailbox.data, ",")) {
@@ -206,7 +206,7 @@ bool HxCommand(void)
   if (show_parms) {
     char item[33];
     dtostrfd((float)Settings.weight_item / 10, 1, item);
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("{\"Sensor34\":{\"" D_JSON_WEIGHT_REF "\":%d,\"" D_JSON_WEIGHT_CAL "\":%d,\"" D_JSON_WEIGHT_MAX "\":%d,\"" D_JSON_WEIGHT_ITEM "\":%s}}"),
+    Response_P(PSTR("{\"Sensor34\":{\"" D_JSON_WEIGHT_REF "\":%d,\"" D_JSON_WEIGHT_CAL "\":%d,\"" D_JSON_WEIGHT_MAX "\":%d,\"" D_JSON_WEIGHT_ITEM "\":%s}}"),
       Settings.weight_reference, Settings.weight_calibration, Settings.weight_max * 1000, item);
   }
 
@@ -348,7 +348,7 @@ void HxShow(bool json)
   dtostrfd(weight, Settings.flag2.weight_resolution, weight_chr);
 
   if (json) {
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"HX711\":{\"" D_JSON_WEIGHT "\":%s%s}"), mqtt_data, weight_chr, scount);
+    ResponseAppend_P(PSTR(",\"HX711\":{\"" D_JSON_WEIGHT "\":%s%s}"), weight_chr, scount);
 #ifdef USE_WEBSERVER
   } else {
     WSContentSend_PD(HTTP_HX711_WEIGHT, weight_chr);
diff --git a/sonoff/xsns_35_tx20.ino b/sonoff/xsns_35_tx20.ino
index 444c5231d..b5e8a2091 100644
--- a/sonoff/xsns_35_tx20.ino
+++ b/sonoff/xsns_35_tx20.ino
@@ -182,8 +182,8 @@ void Tx20Show(bool json)
   GetTextIndexed(wind_direction_string, sizeof(wind_direction_string), tx20_wind_direction, kTx20Directions);
 
   if (json) {
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"TX20\":{\"Speed\":%s,\"SpeedAvg\":%s,\"SpeedMax\":%s,\"Direction\":\"%s\"}"),
-      mqtt_data, wind_speed_string, wind_speed_avg_string, wind_speed_max_string, wind_direction_string);
+    ResponseAppend_P(PSTR(",\"TX20\":{\"Speed\":%s,\"SpeedAvg\":%s,\"SpeedMax\":%s,\"Direction\":\"%s\"}"),
+      wind_speed_string, wind_speed_avg_string, wind_speed_max_string, wind_direction_string);
 #ifdef USE_WEBSERVER
   } else {
     WSContentSend_PD(HTTP_SNS_TX20, wind_speed_string, wind_speed_avg_string, wind_speed_max_string, wind_direction_string);
diff --git a/sonoff/xsns_36_mgc3130.ino b/sonoff/xsns_36_mgc3130.ino
index c767c192c..055126c6d 100644
--- a/sonoff/xsns_36_mgc3130.ino
+++ b/sonoff/xsns_36_mgc3130.ino
@@ -529,8 +529,8 @@ void MGC3130_show(bool json)
   if (json) {
     if (MGC3130_mode == 3 && !MGC3130_triggeredByTouch) {
       if (MGC_data.out.systemInfo.positionValid && !(MGC_data.out.x == MGC3130_lastSentX && MGC_data.out.y == MGC3130_lastSentY && MGC_data.out.z == MGC3130_lastSentZ)) {
-        snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"X\":%u,\"Y\":%u,\"Z\":%u}"),
-          mqtt_data, MGC3130stype, MGC_data.out.x/64, MGC_data.out.y/64, (MGC_data.out.z-(uint16_t)MGC3130_MIN_ZVALUE)/64);
+        ResponseAppend_P(PSTR(",\"%s\":{\"X\":%u,\"Y\":%u,\"Z\":%u}"),
+          MGC3130stype, MGC_data.out.x/64, MGC_data.out.y/64, (MGC_data.out.z-(uint16_t)MGC3130_MIN_ZVALUE)/64);
         MGC3130_lastSentX = MGC_data.out.x;
         MGC3130_lastSentY = MGC_data.out.y;
         MGC3130_lastSentZ = MGC_data.out.z;
@@ -540,7 +540,7 @@ void MGC3130_show(bool json)
 
     if (MGC3130_mode == 2) {
       if (MGC_data.out.systemInfo.airWheelValid && (MGC3130_rotValue != MGC3130_lastSentRotValue)) {
-        snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"AW\":%i}"), mqtt_data, MGC3130stype, MGC3130_rotValue);
+        ResponseAppend_P(PSTR(",\"%s\":{\"AW\":%i}"), MGC3130stype, MGC3130_rotValue);
         MGC3130_lastSentRotValue = MGC3130_rotValue;
       }
     }
@@ -549,7 +549,7 @@ void MGC3130_show(bool json)
       if (millis() - MGC3130_touchTimeStamp > 220 ) {
         MGC3130_touchCounter = 1;
       }
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"%s\":%u}"), mqtt_data, MGC3130stype, MGC3130_currentGesture, MGC3130_touchCounter);
+      ResponseAppend_P(PSTR(",\"%s\":{\"%s\":%u}"), MGC3130stype, MGC3130_currentGesture, MGC3130_touchCounter);
       MGC3130_currentGesture[0] = '\0';
       MGC3130_touchTimeStamp = millis();
     }
diff --git a/sonoff/xsns_37_rfsensor.ino b/sonoff/xsns_37_rfsensor.ino
index 7230ae692..4a94e2d77 100644
--- a/sonoff/xsns_37_rfsensor.ino
+++ b/sonoff/xsns_37_rfsensor.ino
@@ -268,16 +268,16 @@ void RfSnsTheoV2Show(bool json)
 
       if (rfsns_theo_v2_t1[i].time < LocalTime() - RFSNS_VALID_WINDOW) {
         if (json) {
-          snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_RFRECEIVED "\":\"%s\",\"" D_JSON_VOLTAGE "\":%s}"),
-            mqtt_data, sensor, GetDT(rfsns_theo_v2_t1[i].time).c_str(), voltage);
+          ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_RFRECEIVED "\":\"%s\",\"" D_JSON_VOLTAGE "\":%s}"),
+            sensor, GetDT(rfsns_theo_v2_t1[i].time).c_str(), voltage);
         }
       } else {
         char temperature[33];
         dtostrfd(ConvertTemp((float)rfsns_theo_v2_t1[i].temp / 100), Settings.flag2.temperature_resolution, temperature);
 
         if (json) {
-          snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_ILLUMINANCE "\":%d,\"" D_JSON_VOLTAGE "\":%s}"),
-            mqtt_data, sensor, temperature, rfsns_theo_v2_t1[i].lux, voltage);
+          ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_ILLUMINANCE "\":%d,\"" D_JSON_VOLTAGE "\":%s}"),
+            sensor, temperature, rfsns_theo_v2_t1[i].lux, voltage);
 #ifdef USE_DOMOTICZ
           if ((0 == tele_period) && !sensor_once) {
             DomoticzSensor(DZ_TEMP, temperature);
@@ -305,8 +305,8 @@ void RfSnsTheoV2Show(bool json)
 
       if (rfsns_theo_v2_t2[i].time < LocalTime() - RFSNS_VALID_WINDOW) {
         if (json) {
-          snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_RFRECEIVED" \":\"%s\",\"" D_JSON_VOLTAGE "\":%s}"),
-            mqtt_data, sensor, GetDT(rfsns_theo_v2_t2[i].time).c_str(), voltage);
+          ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_RFRECEIVED" \":\"%s\",\"" D_JSON_VOLTAGE "\":%s}"),
+            sensor, GetDT(rfsns_theo_v2_t2[i].time).c_str(), voltage);
         }
       } else {
         float temp = ConvertTemp((float)rfsns_theo_v2_t2[i].temp / 100);
@@ -317,8 +317,8 @@ void RfSnsTheoV2Show(bool json)
         dtostrfd(humi, Settings.flag2.humidity_resolution, humidity);
 
         if (json) {
-          snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s,\"" D_JSON_VOLTAGE "\":%s}"),
-            mqtt_data, sensor, temperature, humidity, voltage);
+          ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s,\"" D_JSON_VOLTAGE "\":%s}"),
+            sensor, temperature, humidity, voltage);
           if ((0 == tele_period) && !sensor_once) {
 #ifdef USE_DOMOTICZ
             DomoticzTempHumSensor(temperature, humidity);  //
@@ -552,8 +552,7 @@ void RfSnsAlectoV2Show(bool json)
   if (rfsns_alecto_v2->time) {
     if (rfsns_alecto_v2->time < LocalTime() - RFSNS_VALID_WINDOW) {
       if (json) {
-        snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"" D_ALECTOV2 "\":{\"" D_JSON_RFRECEIVED "\":\"%s\"}"),
-          mqtt_data, GetDT(rfsns_alecto_v2->time).c_str());
+        ResponseAppend_P(PSTR(",\"" D_ALECTOV2 "\":{\"" D_JSON_RFRECEIVED "\":\"%s\"}"), GetDT(rfsns_alecto_v2->time).c_str());
       }
     } else {
       float temp = ConvertTemp(rfsns_alecto_v2->temp);
@@ -576,8 +575,8 @@ void RfSnsAlectoV2Show(bool json)
       }
 
       if (json) {
-        snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"" D_ALECTOV2 "\":{\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s,\"Rain\":%s,\"Wind\":%s,\"Gust\":%s%s}"),
-          mqtt_data, temperature, humidity, rain, wind, gust, (rfsns_alecto_v2->type) ? direction : "");
+        ResponseAppend_P(PSTR(",\"" D_ALECTOV2 "\":{\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s,\"Rain\":%s,\"Wind\":%s,\"Gust\":%s%s}"),
+          temperature, humidity, rain, wind, gust, (rfsns_alecto_v2->type) ? direction : "");
         if (0 == tele_period) {
 #ifdef USE_DOMOTICZ
         // Use a rules to send data to Domoticz where also a local BMP280 is connected:
diff --git a/sonoff/xsns_38_az7798.ino b/sonoff/xsns_38_az7798.ino
index 953832d6f..2aecab9a1 100644
--- a/sonoff/xsns_38_az7798.ino
+++ b/sonoff/xsns_38_az7798.ino
@@ -258,7 +258,7 @@ void AzShow(bool json)
   dtostrfd(az_humidity, Settings.flag2.humidity_resolution, humidity);
 
   if (json) {
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_CO2 "\":%d,\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s}"), mqtt_data, ktype, az_co2, temperature, humidity);
+    ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_CO2 "\":%d,\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s}"), ktype, az_co2, temperature, humidity);
 #ifdef USE_DOMOTICZ
     if (0 == tele_period) DomoticzSensor(DZ_AIRQUALITY, az_co2);
 #endif  // USE_DOMOTICZ
diff --git a/sonoff/xsns_39_max31855.ino b/sonoff/xsns_39_max31855.ino
index a6275caa7..fc43ecac1 100644
--- a/sonoff/xsns_39_max31855.ino
+++ b/sonoff/xsns_39_max31855.ino
@@ -125,8 +125,8 @@ void MAX31855_Show(bool Json){
     dtostrfd(MAX31855_Result.ReferenceTemperature, Settings.flag2.temperature_resolution, referencetemp);
 
     if(Json){
-        snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_PROBETEMPERATURE "\":%s,\"" D_JSON_REFERENCETEMPERATURE "\":%s,\"" D_JSON_ERROR "\":%d}"), \
-            mqtt_data, "MAX31855", probetemp, referencetemp, MAX31855_Result.ErrorCode);
+        ResponseAppend_P(PSTR(",\"MAX31855\":{\"" D_JSON_PROBETEMPERATURE "\":%s,\"" D_JSON_REFERENCETEMPERATURE "\":%s,\"" D_JSON_ERROR "\":%d}"), \
+          probetemp, referencetemp, MAX31855_Result.ErrorCode);
 #ifdef USE_DOMOTICZ
         if (0 == tele_period) {
           DomoticzSensor(DZ_TEMP, probetemp);
diff --git a/sonoff/xsns_40_pn532.ino b/sonoff/xsns_40_pn532.ino
index 0bfa8bda1..491996327 100644
--- a/sonoff/xsns_40_pn532.ino
+++ b/sonoff/xsns_40_pn532.ino
@@ -497,12 +497,12 @@ void PN532_ScanForTag(void)
       pn532_function = 0;
 #endif // USE_PN532_DATA_FUNCTION
 
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("{\"" D_JSON_TIME "\":\"%s\""), GetDateAndTime(DT_LOCAL).c_str());
+      Response_P(PSTR("{\"" D_JSON_TIME "\":\"%s\""), GetDateAndTime(DT_LOCAL).c_str());
 
 #ifdef USE_PN532_DATA_FUNCTION
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"PN532\":{\"UID\":\"%s\", \"DATA\":\"%s\"}}"), mqtt_data, uids, card_datas);
+      ResponseAppend_P(PSTR(",\"PN532\":{\"UID\":\"%s\", \"DATA\":\"%s\"}}"), uids, card_datas);
 #else
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"PN532\":{\"UID\":\"%s\"}}"), mqtt_data, uids);
+      ResponseAppend_P(PSTR(",\"PN532\":{\"UID\":\"%s\"}}"), uids);
 #endif // USE_PN532_DATA_FUNCTION
 
       MqttPublishPrefixTopic_P(TELE, PSTR(D_RSLT_SENSOR), Settings.flag.mqtt_sensor_retain);
@@ -544,8 +544,7 @@ bool PN532_Command(void)
   if (!strcmp(subStr(sub_string, XdrvMailbox.data, ",", 1),"E")) {
     pn532_function = 1; // Block 1 of next card/tag will be reset to 0x00...
     AddLog_P(LOG_LEVEL_INFO, PSTR("NFC: PN532 NFC - Next scanned tag data block 1 will be erased"));
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("{\"" D_JSON_TIME "\":\"%s\""), GetDateAndTime(DT_LOCAL).c_str());
-    snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"PN532\":{\"COMMAND\":\"E\"\"}}"), mqtt_data);
+    Response_P(PSTR("{\"" D_JSON_TIME "\":\"%s\",\"PN532\":{\"COMMAND\":\"E\"}}"), GetDateAndTime(DT_LOCAL).c_str());
     return serviced;
   }
   if (!strcmp(subStr(sub_string, XdrvMailbox.data, ",", 1),"S")) {
@@ -561,8 +560,7 @@ bool PN532_Command(void)
       pn532_newdata[pn532_newdata_len] = 0x00; // Null terminate the string
       pn532_function = 2;
       AddLog_P2(LOG_LEVEL_INFO, PSTR("NFC: PN532 NFC - Next scanned tag data block 1 will be set to '%s'"), pn532_newdata);
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("{\"" D_JSON_TIME "\":\"%s\""), GetDateAndTime(DT_LOCAL).c_str());
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"PN532\":{\"COMMAND\":\"S\"\"}}"), mqtt_data);
+      Response_P(PSTR("{\"" D_JSON_TIME "\":\"%s\",\"PN532\":{\"COMMAND\":\"S\"}}"), GetDateAndTime(DT_LOCAL).c_str());
       return serviced;
     }
   }
diff --git a/sonoff/xsns_41_max44009.ino b/sonoff/xsns_41_max44009.ino
index 58a809ed9..891b36815 100644
--- a/sonoff/xsns_41_max44009.ino
+++ b/sonoff/xsns_41_max44009.ino
@@ -128,9 +128,7 @@ void Max4409Show(bool json)
     dtostrf(max44009_illuminance, sizeof(illum_str) -1, prec, illum_str);
 
     if (json) {
-      snprintf_P(mqtt_data, sizeof(mqtt_data),
-                 PSTR("%s,\"%s\":{\"" D_JSON_ILLUMINANCE "\":%s}"),
-                 mqtt_data, max44009_types, illum_str);
+      ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_ILLUMINANCE "\":%s}"), max44009_types, illum_str);
 #ifdef USE_DOMOTICZ
       if (0 == tele_period) {
         DomoticzSensor(DZ_ILLUMINANCE, illum_str);
diff --git a/sonoff/xsns_42_scd30.ino b/sonoff/xsns_42_scd30.ino
index defa01892..44e23ea49 100644
--- a/sonoff/xsns_42_scd30.ino
+++ b/sonoff/xsns_42_scd30.ino
@@ -401,7 +401,7 @@ bool Scd30CommandSensor()
           Scd30GetCommand(command_code, &value);
         }
 
-        snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SCD30_COMMAND_NVALUE, command, value);
+        Response_P(S_JSON_SCD30_COMMAND_NVALUE, command, value);
       }
         break;
 
@@ -421,7 +421,7 @@ bool Scd30CommandSensor()
         }
         else
         {
-          snprintf_P(mqtt_data, sizeof(mqtt_data), S_JSON_SCD30_COMMAND_NFW_VALUE, command, major, minor);
+          Response_P(S_JSON_SCD30_COMMAND_NFW_VALUE, command, major, minor);
         }
       }
         break;
@@ -445,8 +445,9 @@ void Scd30Show(bool json)
     dtostrfd(scd30_Humid, Settings.flag2.humidity_resolution, humidity);
     dtostrfd(ConvertTemp(scd30_Temp), Settings.flag2.temperature_resolution, temperature);
     if (json) {
-      //snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"SCD30\":{\"" D_JSON_CO2 "\":%d,\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s}"), mqtt_data, scd30_CO2, temperature, humidity);
-      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"SCD30\":{\"" D_JSON_CO2 "\":%d,\"" D_JSON_ECO2 "\":%d,\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s}"), mqtt_data, scd30_CO2, scd30_CO2EAvg, temperature, humidity);
+      //ResponseAppend_P(PSTR(",\"SCD30\":{\"" D_JSON_CO2 "\":%d,\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s}"), scd30_CO2, temperature, humidity);
+      ResponseAppend_P(PSTR(",\"SCD30\":{\"" D_JSON_CO2 "\":%d,\"" D_JSON_ECO2 "\":%d,\"" D_JSON_TEMPERATURE "\":%s,\"" D_JSON_HUMIDITY "\":%s}"),
+        scd30_CO2, scd30_CO2EAvg, temperature, humidity);
 #ifdef USE_DOMOTICZ
       if (0 == tele_period) DomoticzSensor(DZ_AIRQUALITY, scd30_CO2);
 #endif  // USE_DOMOTICZ