diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8f13d7b..8f31d08 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -25,7 +25,7 @@ idf_component_register(
     PRIV_INCLUDE_DIRS ${libespfs_PRIV_INCLUDE_DIRS}
     PRIV_REQUIRES ${libespfs_PRIV_REQUIRES}
     
-    SRCS "src/WebGUIAppMain.c"
+    SRCS "src/SysConfiguration.c"
     	 "src/romfs.c"
     	 "src/spifs.c"
     	 "src/HTTPServer.c"
@@ -41,6 +41,9 @@ idf_component_register(
     	 "src/MQTT.c"
     	 "src/MQTTSysHandler.c"
     	  src/OTA.c
+    	  src/RestApiHandler.c
+    	  src/SysComm.c
+    	  src/SysErr.c
 #   	 	 "src/mDNS.c"
     	    
     INCLUDE_DIRS  "."
diff --git a/include/HTTPServer.h b/include/HTTPServer.h
index 93d22d4..87a687e 100644
--- a/include/HTTPServer.h
+++ b/include/HTTPServer.h
@@ -41,7 +41,7 @@
 #include "esp_netif.h"
 #include "esp_eth.h"
 #include "mbedtls/base64.h"
-#include "WebGUIAppMain.h"
+#include "SysConfiguration.h"
 
 #define MAX_DYNVAR_NAME_LENGTH 32
 #define MAX_DYNVAR_LENGTH 256
diff --git a/include/WebGUIAppMain.h b/include/SysConfiguration.h
similarity index 93%
rename from include/WebGUIAppMain.h
rename to include/SysConfiguration.h
index e714d49..75f28fc 100644
--- a/include/WebGUIAppMain.h
+++ b/include/SysConfiguration.h
@@ -29,6 +29,24 @@
 #include "esp_netif.h"
 #include "sdkconfig.h"
 
+typedef enum{
+    VAR_BOOL = 0,
+    VAR_INT,
+    VAR_STRING
+} rest_var_types;
+
+typedef struct
+{
+  int id;
+  char alias[32];
+  void* ref;
+  rest_var_types vartype;
+  int minlen;
+  int maxlen;
+} rest_var_t;
+
+
+
 // Application-dependent structure used to contain address information
 
     /**
diff --git a/include/SystemApplication.h b/include/SystemApplication.h
new file mode 100644
index 0000000..64197d2
--- /dev/null
+++ b/include/SystemApplication.h
@@ -0,0 +1,96 @@
+ /*! Copyright 2023 Bogdan Pilyugin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ *  	 \file SystemApplication.h
+ *    \version 1.0
+ * 		 \date 2023-07-26
+ *     \author Bogdan Pilyugin
+ * 	    \brief    
+ *    \details 
+ *	\copyright Apache License, Version 2.0
+ */
+
+#ifndef COMPONENTS_WEBGUIAPP_INCLUDE_SYSTEMAPPLICATION_H_
+#define COMPONENTS_WEBGUIAPP_INCLUDE_SYSTEMAPPLICATION_H_
+#include "webguiapp.h"
+#include "esp_err.h"
+#include "jRead.h"
+#include "jWrite.h"
+
+#define EXPECTED_MAX_DATA_RESPONSE_SIZE (4096)
+
+typedef enum
+{
+    SYS_OK_DATA = 0,
+    SYS_OK,
+
+    SYS_ERROR_WRONG_JSON_FORMAT = 200,
+    SYS_ERROR_PARSE_DATA,
+    SYS_ERROR_SHA256_DATA,
+
+    SYS_ERROR_PARSE_SIGNATURE,
+    SYS_ERROR_PARSE_MESSAGEID,
+    SYS_ERROR_PARSE_MSGTYPE,
+    SYS_ERROR_PARSE_PAYLOADTYPE,
+
+    SYS_ERROR_PARSE_KEY1,
+    SYS_ERROR_PARSE_KEY2,
+
+    SYS_ERROR_NO_MEMORY = 300,
+    SYS_ERROR_UNKNOWN,
+
+} sys_error_code;
+
+typedef enum
+{
+    MSG_COMMAND = 1,
+    MSG_REQUEST,
+    MSG_RESPONSE
+} msg_type;
+
+typedef struct
+{
+int key1;
+int key2;
+
+} payload_type_50;
+
+
+#define DATA_MESSAGE_TYPE_COMMAND  (1)
+#define DATA_MESSAGE_TYPE_REQUEST  (2)
+#define DATA_MESSAGE_TYPE_RESPONSE  (3)
+
+typedef struct
+{
+    char *inputDataBuffer;
+    int inputDataLength;
+    int chlidx;
+    char *outputDataBuffer;
+    int outputDataLength;
+    struct
+    {
+        uint64_t msgID;
+        time_t time;
+        int msgType;
+        int payloadType;
+        void *payload;
+        unsigned char sha256[32];
+    } parsedData;
+    int err_code;
+} data_message_t;
+
+esp_err_t SysServiceDataHandler(data_message_t *MSG);
+void GetSysErrorDetales(sys_error_code err, const char **br, const char **ds);
+
+#endif /* COMPONENTS_WEBGUIAPP_INCLUDE_SYSTEMAPPLICATION_H_ */
diff --git a/src/ETHTransport.c b/src/ETHTransport.c
index 2d86364..ef8d975 100644
--- a/src/ETHTransport.c
+++ b/src/ETHTransport.c
@@ -21,7 +21,7 @@
 
 #include <stdio.h>
 #include <string.h>
-#include <WebGUIAppMain.h>
+#include <SysConfiguration.h>
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
 #include "esp_netif.h"
diff --git a/src/GSMTransport.c b/src/GSMTransport.c
index c446603..1a1c93c 100644
--- a/src/GSMTransport.c
+++ b/src/GSMTransport.c
@@ -21,7 +21,7 @@
 
 #include <string.h>
 
-#include "../include/WebGUIAppMain.h"
+#include "../include/SysConfiguration.h"
 #include "freertos/FreeRTOS.h"
 #include "freertos/event_groups.h"
 #include "freertos/task.h"
diff --git a/src/HTTPAPISystem.c b/src/HTTPAPISystem.c
index 14d844a..0808be3 100644
--- a/src/HTTPAPISystem.c
+++ b/src/HTTPAPISystem.c
@@ -20,10 +20,10 @@
  */
 
 #include "HTTPServer.h"
-#include "jWrite.h"
-#include "jRead.h"
+#include "SystemApplication.h"
 
-#define API_VER "1.00"
+#define SYS_API_VER "1.00"
+#define TAG "HTTPAPISystem"
 
 HTTP_IO_RESULT HTTPPostSysAPI(httpd_req_t *req, char *PostData)
 {
@@ -31,23 +31,26 @@ HTTP_IO_RESULT HTTPPostSysAPI(httpd_req_t *req, char *PostData)
     httpd_req_get_hdr_value_str(req, "Content-Type", (char*) data, 31);
     if (!memcmp(data, "application/json", sizeof("application/json")))
     {
-        char key[32] = {0};
-        struct jReadElement result;
-        jRead(PostData, "", &result);
-        if (result.dataType == JREAD_OBJECT)
+        char *respbuf = malloc(EXPECTED_MAX_DATA_RESPONSE_SIZE);
+        if (respbuf)
         {
-            jRead_string(PostData, "{'key'", key, sizeof(key), NULL);
+            data_message_t M = { 0 };
+            M.inputDataBuffer = PostData;
+            M.inputDataLength = strlen(PostData);
+            M.chlidx = 100;
+            M.outputDataBuffer = respbuf;
+            M.outputDataLength = EXPECTED_MAX_DATA_RESPONSE_SIZE;
+            SysServiceDataHandler(&M);
+            httpd_resp_sendstr(req, respbuf);
+            free(respbuf);
+            return HTTP_IO_DONE_API;
+        }
+        else
+        {
+            ESP_LOGE(TAG, "Out of free RAM for HTTP API handle");
+            httpd_resp_set_status(req, HTTPD_500);
+            return HTTP_IO_DONE_API;
         }
-
-        //ESP_LOGI(TAG, "JSON data:%s", PostData);
-        jwOpen(data, sizeof(data), JW_OBJECT, JW_COMPACT);
-        jwObj_string("apiver", API_VER);
-        jwObj_string("key", key);;
-        jwObj_raw("result", "OK");
-        jwEnd();
-        jwClose();
-        httpd_resp_sendstr(req, data);
-        return HTTP_IO_DONE_API;
     }
 
     httpd_resp_set_status(req, HTTPD_400);
diff --git a/src/HTTPServer.c b/src/HTTPServer.c
index bdb2704..b9f6a54 100644
--- a/src/HTTPServer.c
+++ b/src/HTTPServer.c
@@ -363,11 +363,8 @@ static esp_err_t GETHandler(httpd_req_t *req)
 
 
 //check if the file can contains dynamic variables
-    if (IS_FILE_EXT(filename, ".html") ||
-            IS_FILE_EXT(filename, ".json") ||
-            IS_FILE_EXT(filename, ".css") ||
-            IS_FILE_EXT(filename, ".js"))
-        isDynamicVars = false;
+    if (IS_FILE_EXT(filename, ".json") )
+        isDynamicVars = true;
 
 
 //check if file is compressed by GZIP and add correspondent header
diff --git a/src/LoRaWAN.c b/src/LoRaWAN.c
index 0baef4a..81c193f 100644
--- a/src/LoRaWAN.c
+++ b/src/LoRaWAN.c
@@ -28,7 +28,8 @@
 #include "NetTransport.h"
 #include "webguiapp.h"
 #include "LoRaWAN.h"
-#include "../include/WebGUIAppMain.h"
+
+#include "../include/SysConfiguration.h"
 
 // Pins and other resources
 /*Defined in global configuration*/
diff --git a/src/MQTT.c b/src/MQTT.c
index fa2d35a..61e7ac1 100644
--- a/src/MQTT.c
+++ b/src/MQTT.c
@@ -18,7 +18,8 @@
  *      Author: Bogdan Pilyugin
  * Description:	
  */
-#include <WebGUIAppMain.h>
+#include <SysConfiguration.h>
+#include <SystemApplication.h>
 #include "esp_log.h"
 #include "Helpers.h"
 #include "NetTransport.h"
@@ -108,6 +109,30 @@ void ComposeTopic(char *topic, int idx, char *service_name, char *direct)
     strcat((char*) topic, direct);  // Data direction UPLINK or DOWNLINK
 }
 
+esp_err_t SysServiceMQTTSend(char *data, int len, int idx)
+{
+    if (GetMQTTHandlesPool(idx)->mqtt_queue == NULL)
+        return ESP_ERR_NOT_FOUND;
+    char *buf = (char*) malloc(len);
+    if (buf)
+    {
+        memcpy(buf, data, len);
+        MQTT_DATA_SEND_STRUCT DSS;
+        ComposeTopic(DSS.topic, idx, "SYSTEM", "UPLINK");
+        DSS.raw_data_ptr = buf;
+        DSS.data_length = len;
+        if (xQueueSend(GetMQTTHandlesPool(idx)->mqtt_queue, &DSS, pdMS_TO_TICKS(1000)) == pdPASS)
+            return ESP_OK;
+        else
+        {
+            free(buf);
+            return ESP_ERR_TIMEOUT;
+        }
+    }
+    return ESP_ERR_NO_MEM;
+}
+
+
 static void mqtt_system_event_handler(int idx, void *handler_args, esp_event_base_t base, int32_t event_id,
                                       void *event_data)
 {
@@ -174,10 +199,26 @@ static void mqtt_system_event_handler(int idx, void *handler_args, esp_event_bas
             ComposeTopic(topic, idx, "SYSTEM", "DWLINK");
             if (!memcmp(topic, event->topic, event->topic_len))
             {
-                SystemDataHandler(event->data, event->data_len, idx);
-#if MQTT_DEBUG_MODE > 0
-                ESP_LOGI(TAG, "Control data handler on client %d", idx);
+                //SystemDataHandler(event->data, event->data_len, idx);  //Old API
+                char *respbuf = malloc(EXPECTED_MAX_DATA_RESPONSE_SIZE);
+                if (respbuf != NULL)
+                {
+                    data_message_t M = { 0 };
+                    M.inputDataBuffer = event->data;
+                    M.inputDataLength = event->data_len;
+                    M.chlidx = idx;
+                    M.outputDataBuffer = respbuf;
+                    M.outputDataLength = EXPECTED_MAX_DATA_RESPONSE_SIZE;
+                    SysServiceDataHandler(&M);
+                    SysServiceMQTTSend(M.outputDataBuffer, strlen(M.outputDataBuffer), idx);
+                    free(respbuf);
+#if(MQTT_DEBUG_MODE > 0)
+                    ESP_LOGI(TAG, "SERVICE data handler on client %d", idx);
 #endif
+                }
+                else
+                    ESP_LOGE(TAG, "Out of free RAM for MQTT API handle");
+
             }
         break;
         case MQTT_EVENT_ERROR:
diff --git a/src/NetTransport.c b/src/NetTransport.c
index f225d70..0d2dd1e 100644
--- a/src/NetTransport.c
+++ b/src/NetTransport.c
@@ -19,7 +19,7 @@
  * Description:	
  */
 
-#include <WebGUIAppMain.h>
+#include <SysConfiguration.h>
 #include "NetTransport.h"
 #include "sdkconfig.h"
 #include "lwip/netif.h"
diff --git a/src/OTA.c b/src/OTA.c
index 464a747..741305b 100644
--- a/src/OTA.c
+++ b/src/OTA.c
@@ -34,7 +34,7 @@
 #include "nvs.h"
 
 #include <sys/socket.h>
-#include <WebGUIAppMain.h>
+#include <SysConfiguration.h>
 #include "NetTransport.h"
 
 TaskHandle_t ota_task_handle;
diff --git a/src/RestApiHandler.c b/src/RestApiHandler.c
new file mode 100644
index 0000000..2bad915
--- /dev/null
+++ b/src/RestApiHandler.c
@@ -0,0 +1,88 @@
+ /*! Copyright 2023 Bogdan Pilyugin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ *  	 \file RestApiHandler.c
+ *    \version 1.0
+ * 		 \date 2023-07-26
+ *     \author Bogdan Pilyugin
+ * 	    \brief    
+ *    \details 
+ *	\copyright Apache License, Version 2.0
+ */
+
+#include <SysConfiguration.h>
+#include <webguiapp.h>
+
+extern SYS_CONFIG SysConfig;
+
+const rest_var_t ConfigVariables[] =
+{
+        {0, "netname", &SysConfig.NetBIOSName, VAR_STRING, 3, 31},
+        {1, "otaurl", &SysConfig.OTAURL, VAR_STRING, 3, 128}
+
+};
+
+esp_err_t SetConfVar(char* valias, rest_var_types* vtype, void* val)
+{
+    rest_var_t *V = NULL;
+    for (int i = 0; i< sizeof(ConfigVariables)/sizeof(rest_var_t); ++i)
+    {
+        if (!strcmp(ConfigVariables[i].alias, valias))
+        {
+            V = &ConfigVariables[i];
+            break;
+        }
+    }
+    if (!V) return ESP_ERR_NOT_FOUND;
+    int vallen = strlen(val);
+    if (vallen < V->minlen || vallen >= V->maxlen)
+        return ESP_ERR_INVALID_ARG;
+
+    switch(*vtype)
+    {
+        case VAR_BOOL:
+            V->ref = (val)?true:false;
+            break;
+        case VAR_INT:
+            V->ref = (int*)val;
+            break;
+        case VAR_STRING:
+            strcpy(V->ref, (char*)val);
+            break;
+
+    }
+    return ESP_OK;
+}
+
+
+esp_err_t GetConfVar(char* valias, rest_var_types* vtype, void* val)
+{
+    rest_var_types *faketp  = vtype;
+    void *fakepointer = val;
+    rest_var_t *V = NULL;
+    for (int i = 0; i< sizeof(ConfigVariables)/sizeof(rest_var_t); ++i)
+    {
+        if (!strcmp(ConfigVariables[i].alias, valias))
+        {
+            V = &ConfigVariables[i];
+            break;
+        }
+    }
+    if (!V) return ESP_ERR_NOT_FOUND;
+    vtype = &V->vartype;
+    val = V->ref;
+    return ESP_OK;
+}
+
+
diff --git a/src/SysComm.c b/src/SysComm.c
new file mode 100644
index 0000000..cec89a8
--- /dev/null
+++ b/src/SysComm.c
@@ -0,0 +1,263 @@
+/*! Copyright 2023 Bogdan Pilyugin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ *  	 \file SysComm.c
+ *    \version 1.0
+ * 		 \date 2023-07-26
+ *     \author Bogdan Pilyugin
+ * 	    \brief    
+ *    \details 
+ *	\copyright Apache License, Version 2.0
+ */
+
+/*
+ //Example of remote transaction [payloadtype=1]  start[msgtype=1]
+ {
+ "data":{
+ "msgid":123456789,
+ "time":"2023-06-03T12:25:24+00:00",
+ "msgtype":1,
+ "payloadtype":50,
+ "payload":{
+ "key1":"value1",
+ "key2":"value2"}},
+ "signature":"6a11b872e8f766673eb82e127b6918a0dc96a42c5c9d184604f9787f3d27bcef"}
+
+
+ //Example of request [msgtype=2] of information related to transaction [payloadtype=1]
+ {
+ "data":{
+ "msgid":123456789,
+ "time":"2023-06-03T12:25:24+00:00",
+ "msgtype":2,
+ "payloadtype":50},
+ "signature":"3c1254d5b0e7ecc7e662dd6397554f02622ef50edba18d0b30ecb5d53e409bcb"}
+
+
+ //Example of response [msgtype=3] to request related to the transaction [payloadtype=1]
+ {
+ "data":{
+ "msgid":123456789,
+ "time":"2023-06-03T12:25:24+00:00",
+ "msgtype": 3,
+ "payloadtype":50,
+ "payload":{
+ "key1":"value1",
+ "key2":"value2"},
+ "error":"SYS_OK",
+ "error_descr":"Result successful"},
+ "signature":"0d3b545b7c86274a6bf5a6e606b260f32b1999de40cb7d29d0949ecc9389cd9d"}
+
+ */
+
+#include "webguiapp.h"
+#include "SystemApplication.h"
+#include "mbedtls/md.h"
+
+#define TAG "SysComm"
+
+#define MAX_JSON_DATA_SIZE 1024
+
+static esp_err_t SHA256hmacHash(unsigned char *data,
+                                int datalen,
+                                unsigned char *key,
+                                int keylen,
+                                unsigned char *res)
+{
+    mbedtls_md_context_t ctx;
+    mbedtls_md_type_t md_type = MBEDTLS_MD_SHA256;
+    mbedtls_md_init(&ctx);
+    mbedtls_md_setup(&ctx, mbedtls_md_info_from_type(md_type), 1);
+    mbedtls_md_hmac_starts(&ctx, key, keylen);
+    mbedtls_md_hmac_update(&ctx, (const unsigned char*) data, datalen);
+    mbedtls_md_hmac_finish(&ctx, res);
+    mbedtls_md_free(&ctx);
+    return ESP_OK;
+}
+
+static void Timestamp(char *ts)
+{
+    struct timeval tp;
+    gettimeofday(&tp, NULL);
+    unsigned long long ms = (((unsigned long long) tp.tv_sec) * 1000000 + tp.tv_usec);
+    sprintf(ts, "%llu", ms);
+}
+
+void PrepareResponsePayloadType50(data_message_t *MSG)
+{
+    const char *err_br;
+    const char *err_desc;
+    jwOpen(MSG->outputDataBuffer, MSG->outputDataLength, JW_OBJECT, JW_PRETTY);
+    jwObj_int("msgid", MSG->parsedData.msgID);
+    char time[RFC3339_TIMESTAMP_LENGTH];
+    GetRFC3339Time(time);
+    jwObj_string("time", time);
+    jwObj_int("messtype", DATA_MESSAGE_TYPE_RESPONSE);
+    jwObj_int("payloadtype", 50);
+    //PAYLOAD BEGIN
+    jwObj_object("payload");
+
+    jwObj_string("param1", "value1");
+    jwObj_string("param2", "value2");
+
+    jwEnd();
+    GetSysErrorDetales((sys_error_code) MSG->err_code, &err_br, &err_desc);
+    jwObj_string("error", (char*) err_br);
+    jwObj_string("error_descr", (char*) err_desc);
+    jwEnd();
+    jwClose();
+}
+
+static sys_error_code SysPayloadType50Handler(data_message_t *MSG)
+{
+    struct jReadElement result;
+    payload_type_50 *payload;
+    payload = ((payload_type_50*) (MSG->parsedData.payload));
+    if (MSG->parsedData.msgType == DATA_MESSAGE_TYPE_COMMAND)
+    {
+        //Extract 'key1' or throw exception
+        jRead(MSG->inputDataBuffer, "{'data'{'payload'{'key1'", &result);
+        if (result.elements == 1)
+        {
+
+        }
+        else
+            return SYS_ERROR_PARSE_KEY1;
+
+        //Extract 'key1' or throw exception
+        jRead(MSG->inputDataBuffer, "{'data'{'payload'{'key2'", &result);
+        if (result.elements == 1)
+        {
+
+        }
+        else
+            return SYS_ERROR_PARSE_KEY2;
+        //return StartTransactionPayloadType1(MSG);
+
+    }
+
+    else if (MSG->parsedData.msgType == DATA_MESSAGE_TYPE_REQUEST)
+    {
+        PrepareResponsePayloadType50(MSG);
+        return SYS_OK_DATA;
+    }
+    else
+        return SYS_ERROR_PARSE_MSGTYPE;
+
+    return SYS_OK;
+}
+
+static sys_error_code SysDataParser(data_message_t *MSG)
+{
+    struct jReadElement result;
+    jRead(MSG->inputDataBuffer, "", &result);
+    if (result.dataType != JREAD_OBJECT)
+        return SYS_ERROR_WRONG_JSON_FORMAT;
+    MSG->parsedData.msgID = 0;
+
+    char *hashbuf = malloc(MSG->inputDataLength);
+    if (hashbuf == NULL)
+        return SYS_ERROR_NO_MEMORY;
+    jRead_string(MSG->inputDataBuffer, "{'data'", hashbuf, MSG->inputDataLength, 0);
+    if (strlen(hashbuf) > 0)
+    {
+        SHA256hmacHash((unsigned char*) hashbuf, strlen(hashbuf), (unsigned char*) "mykey", sizeof("mykey"),
+                       MSG->parsedData.sha256);
+        unsigned char sha_print[32 * 2 + 1];
+        BytesToStr(MSG->parsedData.sha256, sha_print, 32);
+        sha_print[32 * 2] = 0x00;
+        ESP_LOGI(TAG, "SHA256 of DATA object is %s", sha_print);
+        free(hashbuf);
+    }
+    else
+    {
+        free(hashbuf);
+        return SYS_ERROR_PARSE_DATA;
+    }
+
+    jRead(MSG->inputDataBuffer, "{'signature'", &result);
+    if (result.elements == 1)
+    {
+        ESP_LOGI(TAG, "Signature is %.*s", 64, (char* )result.pValue);
+        //Here compare calculated and received signature;
+    }
+    else
+        return SYS_ERROR_PARSE_SIGNATURE;
+
+    //Extract 'messidx' or throw exception
+    jRead(MSG->inputDataBuffer, "{'data'{'msgid'", &result);
+    if (result.elements == 1)
+    {
+        MSG->parsedData.msgID = jRead_long(MSG->inputDataBuffer, "{'data'{'msgid'", 0);
+        if (MSG->parsedData.msgID == 0)
+            return SYS_ERROR_PARSE_MESSAGEID;
+    }
+    else
+        return SYS_ERROR_PARSE_MESSAGEID;
+
+    //Extract 'msgtype' or throw exception
+    jRead(MSG->inputDataBuffer, "{'data'{'msgtype'", &result);
+    if (result.elements == 1)
+    {
+        MSG->parsedData.msgType = atoi((char*) result.pValue);
+        if (MSG->parsedData.msgType > 2 || MSG->parsedData.msgType < 1)
+            return SYS_ERROR_PARSE_MSGTYPE;
+    }
+    else
+        return SYS_ERROR_PARSE_MSGTYPE;
+
+    //Extract 'payloadtype' or throw exception
+    jRead(MSG->inputDataBuffer, "{'data'{'payloadtype'", &result);
+    if (result.elements == 1)
+    {
+        MSG->parsedData.payloadType = atoi((char*) result.pValue);
+        if (MSG->parsedData.payloadType < 1 && MSG->parsedData.payloadType > 100)
+            return SYS_ERROR_PARSE_PAYLOADTYPE;
+        MSG->parsedData.payload = malloc(sizeof(payload_type_50));
+    }
+    else
+        return SYS_ERROR_PARSE_PAYLOADTYPE;
+
+    switch (MSG->parsedData.payloadType)
+    {
+        case 50:
+            return SysPayloadType50Handler(MSG);
+        break;
+    }
+
+    return SYS_ERROR_UNKNOWN;
+}
+
+esp_err_t SysServiceDataHandler(data_message_t *MSG)
+{
+    MSG->err_code = (int) SysDataParser(MSG);
+    if (MSG->err_code)
+    {
+        jwOpen(MSG->outputDataBuffer, MSG->outputDataLength, JW_OBJECT, JW_PRETTY);
+        jwObj_int("msgid", MSG->parsedData.msgID);
+        char time[RFC3339_TIMESTAMP_LENGTH];
+        GetRFC3339Time(time);
+        jwObj_string("time", time);
+        jwObj_int("messtype", DATA_MESSAGE_TYPE_RESPONSE);
+        const char *err_br;
+        const char *err_desc;
+        GetSysErrorDetales((sys_error_code) MSG->err_code, &err_br, &err_desc);
+        jwObj_string("error", (char*) err_br);
+        jwObj_string("error_descr", (char*) err_desc);
+        jwEnd();
+        jwClose();
+    }
+
+    return ESP_OK;
+}
diff --git a/src/WebGUIAppMain.c b/src/SysConfiguration.c
similarity index 96%
rename from src/WebGUIAppMain.c
rename to src/SysConfiguration.c
index 6d7560c..62c13e7 100644
--- a/src/WebGUIAppMain.c
+++ b/src/SysConfiguration.c
@@ -21,8 +21,9 @@
  *	\copyright Apache License, Version 2.0
  */
 
-#include "WebGUIAppMain.h"
+#include "../include/SysConfiguration.h"
 
+#include "SystemApplication.h"
 #include <webguiapp.h>
 #include "stdlib.h"
 #include "string.h"
diff --git a/src/SysErr.c b/src/SysErr.c
new file mode 100644
index 0000000..e34442f
--- /dev/null
+++ b/src/SysErr.c
@@ -0,0 +1,72 @@
+ /*! Copyright 2023 Bogdan Pilyugin
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ *  	 \file SysErr.c
+ *    \version 1.0
+ * 		 \date 2023-07-26
+ *     \author Bogdan Pilyugin
+ * 	    \brief    
+ *    \details 
+ *	\copyright Apache License, Version 2.0
+ */
+
+#include "SystemApplication.h"
+
+typedef struct
+{
+    sys_error_code errcode;
+    char *errbreaf;
+    char *errdescr;
+} sys_error_t;
+
+const sys_error_t SysErrors[] = {
+        {SYS_OK_DATA, "SYS_OK_DATA", "Result successful, data attached" },
+        {SYS_OK, "SYS_OK", "Result successful" },
+
+        { SYS_ERROR_WRONG_JSON_FORMAT, "SYS_ERROR_WRONG_JSON_FORMAT", "Wrong JSON format or not JSON data" },
+        { SYS_ERROR_PARSE_DATA, "SYS_ERROR_PARSE_PAYLOAD", "Payload object not found"},
+        { SYS_ERROR_SHA256_DATA, "SYS_ERROR_SHA256_PAYLOAD", "SHA256 signature is not valid"},
+        { SYS_ERROR_PARSE_SIGNATURE, "SYS_ERROR_PARSE_SIGNATURE", "Key 'signature' not found"},
+        { SYS_ERROR_PARSE_MESSAGEID, "SYS_ERROR_PARSE_MESSAGEID", "Key 'msgid' not found or have illegal value" },
+        { SYS_ERROR_PARSE_MSGTYPE, "SYS_ERROR_PARSE_MSGTYPE", "Key 'msgtype' not found or have illegal value"},
+        { SYS_ERROR_PARSE_PAYLOADTYPE, "SYS_ERROR_PARSE_PAYLOADTYPE", "Key 'payloadtype' not found or have illegal value"},
+
+        { SYS_ERROR_PARSE_KEY1, "SYS_ERROR_PARSE_KEY1", "Key 'key1' not found or have illegal value"},
+        { SYS_ERROR_PARSE_KEY2, "SYS_ERROR_PARSE_KEY2", "Key 'key2' not found or have illegal value"},
+
+        { SYS_ERROR_NO_MEMORY, "SYS_ERROR_NO_MEMORY", "ERROR allocate memory for JSON parser" },
+        { SYS_ERROR_UNKNOWN, "SYS_ERROR_UNKNOWN", "Unknown ERROR" }
+
+};
+
+void GetSysErrorDetales(sys_error_code err, const char **br, const char **ds)
+{
+    *br = SysErrors[sizeof(SysErrors) / sizeof(sys_error_t) - 1].errbreaf;
+    *ds = SysErrors[sizeof(SysErrors) / sizeof(sys_error_t) - 1].errdescr;
+
+    for (int i = 0; i < sizeof(SysErrors) / sizeof(sys_error_t); i++)
+    {
+        if (err == SysErrors[i].errcode)
+        {
+            *br = SysErrors[i].errbreaf;
+            *ds = SysErrors[i].errdescr;
+            return;
+        }
+    }
+    return;
+}
+
+#define TAG "SysErr"
+
+
diff --git a/src/WiFiTransport.c b/src/WiFiTransport.c
index 7a0fc5c..7706b9b 100644
--- a/src/WiFiTransport.c
+++ b/src/WiFiTransport.c
@@ -19,7 +19,7 @@
  * Description:	
  */
 
-#include "WebGUIAppMain.h"
+#include <SysConfiguration.h>
 #include "esp_log.h"
 #include "Helpers.h"
 #include "esp_system.h"