diff --git a/Makefile b/Makefile
index 4138886..ccf379f 100644
--- a/Makefile
+++ b/Makefile
@@ -101,7 +101,7 @@ LED_SERIAL_PIN      ?= 14
 # --------------- esp-link modules config options ---------------
 
 # Optional Modules mqtt
-MODULES ?= mqtt rest syslog
+MODULES ?= mqtt rest syslog web-server
 
 # --------------- esphttpd config options ---------------
 
@@ -220,6 +220,10 @@ ifneq (,$(findstring syslog,$(MODULES)))
 	CFLAGS		+= -DSYSLOG
 endif
 
+ifneq (,$(findstring web-server,$(MODULES)))
+	CFLAGS		+= -DWEBSERVER
+endif
+
 # which modules (subdirectories) of the project to include in compiling
 LIBRARIES_DIR 	= libraries
 MODULES		  	+= espfs httpd user serial cmd esp-link
diff --git a/WEB-SERVER.md b/WEB-SERVER.md
new file mode 100644
index 0000000..6bd2a3c
--- /dev/null
+++ b/WEB-SERVER.md
@@ -0,0 +1,44 @@
+ESP-LINK web-server tutorial
+============================
+
+LED flashing sample
+--------------------
+
+Circuit:
+
+ - 1: connect a Nodemcu (ESP8266) board and an Arduino Nano / UNO:
+   (RX - levelshifter - TX, TX - levelshifter - RX)
+ - 2: optionally connect RESET-s with a level shifter
+
+
+Installation steps:
+
+ - 1: install the latest Arduino on the PC
+ - 2: install EspLink library from arduino/libraries path
+ - 3: open EspLinkWebSimpleLedControl sample from Arduino
+ - 4: upload the code onto an Arduino Nano/Uno
+ - 5: install esp-link
+ - 6: jump to the Web Server page on esp-link UI
+ - 7: upload SimpleLED.html ( arduino/libraries/EspLink/examples/EspLinkWebSimpleLedControl/SimpleLED.html )
+ - 8: jump to SimpleLED page on esp-link UI
+ - 9: turn on/off the LED
+
+Complex application sample
+--------------------------
+
+Circuit:
+
+ - 1: connect a Nodemcu (ESP8266) board and an Arduino Nano / UNO:
+   (RX - levelshifter - TX, TX - levelshifter - RX)
+ - 2: optionally connect RESET-s with a level shifter
+ - 3: add a trimmer to A0 for Voltage measurement
+
+Installation steps:
+
+ - 1: open EspLinkWebApp sample from Arduino
+ - 2: upload the code onto an Arduino Nano/Uno
+ - 3: jump to the Web Server page on esp-link UI
+ - 4: upload web-page.espfs.img (  arduino/libraries/EspLink/examples/EspLinkWebApp/web-page.espfs.img )
+ - 5: jump to LED/User/Voltage pages
+ - 6: try out different settings
+ 
diff --git a/arduino/libraries/EspLink/EspLink.cpp b/arduino/libraries/EspLink/EspLink.cpp
new file mode 100644
index 0000000..0e2972a
--- /dev/null
+++ b/arduino/libraries/EspLink/EspLink.cpp
@@ -0,0 +1,207 @@
+#include "EspLink.h"
+
+#define READ_BUF_DFLT_SIZE 64
+
+// Standard SLIP escape chars from RFC
+#define SLIP_END      0300    // indicates end of packet
+#define SLIP_ESC      0333    // indicates byte stuffing
+#define SLIP_ESC_END  0334    // ESC ESC_END means END data byte
+#define SLIP_ESC_ESC  0335    // ESC ESC_ESC means ESC data byte
+
+EspLink::EspLink(Stream &streamIn, CmdRequestCB callback):stream(streamIn),requestCb(callback)
+{
+  readBuf = NULL;
+  readLastChar = 0;
+}
+
+EspLink::~EspLink()
+{
+  if( readBuf != NULL )
+    free( readBuf );
+  readBuf = NULL;
+}
+    
+void EspLink::writeChar(uint8_t data)
+{
+  switch(data)
+  {
+  case SLIP_END:
+    stream.write(SLIP_ESC);
+    stream.write(SLIP_ESC_END);
+    break;
+  case SLIP_ESC:
+    stream.write(SLIP_ESC);
+    stream.write(SLIP_ESC_ESC);
+    break;
+  default:
+    stream.write(data);
+  }
+
+  crc16_add(data, &crc16_out);
+}
+
+/* CITT CRC16 polynomial ^16 + ^12 + ^5 + 1 */
+/*---------------------------------------------------------------------------*/
+void EspLink::crc16_add(uint8_t b, uint16_t *crc)
+{
+  *crc ^= b;
+  *crc  = (*crc >> 8) | (*crc << 8);
+  *crc ^= (*crc & 0xff00) << 4;
+  *crc ^= (*crc >> 8) >> 4;
+  *crc ^= (*crc & 0xff00) >> 5;
+}
+
+void EspLink::writeBuf(uint8_t * buf, uint16_t len)
+{
+  while(len-- > 0)
+    writeChar(*buf++);
+}
+
+void EspLink::sendPacketStart(uint16_t cmd, uint32_t value, uint16_t argc)
+{
+  crc16_out = 0;
+  stream.write( SLIP_END );
+  writeBuf((uint8_t*)&cmd, 2);
+  writeBuf((uint8_t*)&argc, 2);
+  writeBuf((uint8_t*)&value, 4);
+}
+
+void EspLink::sendPacketArg(uint16_t len, uint8_t * data)
+{
+  writeBuf((uint8_t*)&len, 2);
+  writeBuf(data, len);
+
+  uint16_t pad = ((len+3)&~3) - len; // get to multiple of 4
+  if (pad > 0) {
+    uint32_t temp = 0;
+    writeBuf((uint8_t*)&temp, pad);
+  }
+}
+
+void EspLink::sendPacketEnd() {
+  uint16_t crc = crc16_out;
+  writeBuf((uint8_t*)&crc, 2);
+  stream.write(SLIP_END);
+}
+
+void EspLink::parseSlipPacket()
+{
+  CmdRequest req;
+  req.cmd = (CmdPacket *)readBuf;
+  req.arg_num = 0;
+  req.arg_ptr = readBuf + sizeof(CmdPacket);
+
+  requestCb(&req);
+
+  free(readBuf);
+  readBuf = NULL;
+}
+
+void EspLink::checkPacket()
+{
+  if( readBufPtr <= 3 )
+    return;
+  uint16_t crc = 0;
+  for(uint16_t i=0; i < readBufPtr - 2; i++)
+    crc16_add(readBuf[i], &crc);
+
+  uint16_t crcpacket = *(uint16_t*)(readBuf + readBufPtr - 2);
+
+  if( crc == crcpacket )
+  {
+    readBufPtr -= 2;
+    parseSlipPacket();
+  }
+}
+
+void EspLink::readLoop()
+{
+  if( stream.available() > 0 )
+  {
+    int byt = stream.read();
+
+    switch(readState)
+    {
+      case WAIT_FOR_SLIP_START:
+        if( byt == SLIP_END )
+        {
+          if(readBuf != NULL)
+            free(readBuf);
+          readBufPtr = 0;
+          readBufMax = READ_BUF_DFLT_SIZE;
+          readBuf = (uint8_t *)malloc(readBufMax);
+          readState = READ_SLIP_PACKAGE;
+        }
+        break;
+      case READ_SLIP_PACKAGE:
+        if( byt == SLIP_END )
+        {
+          readState = WAIT_FOR_SLIP_START;
+          checkPacket();
+          break;
+        }
+        if( byt == SLIP_ESC )
+          break;
+        if( readLastChar == SLIP_ESC && byt == SLIP_ESC_END )
+          byt = SLIP_END;
+        else if( readLastChar == SLIP_ESC && byt == SLIP_ESC_ESC )
+          byt = SLIP_ESC;
+
+        if( readBufPtr >= readBufMax )
+        {
+          readBufMax = readBufMax + READ_BUF_DFLT_SIZE;
+          readBuf = (uint8_t *)realloc(readBuf, readBufMax);
+          if( readBuf == NULL )
+          {
+            readState = WAIT_FOR_SLIP_START; // TODO
+            break;
+          }
+        }
+        readBuf[readBufPtr++] = byt;
+        break;
+    }
+
+    readLastChar = byt;
+  }
+}
+
+// Return the number of arguments given a command struct
+uint32_t EspLink::cmdGetArgc(CmdRequest *req) {
+  return req->cmd->argc;
+}
+
+// Copy the next argument from a command structure into the data pointer, returns 0 on success
+// -1 on error
+int32_t EspLink::cmdPopArg(CmdRequest *req, void *data, uint16_t len) {
+  uint16_t length;
+
+  if (req->arg_num >= req->cmd->argc)
+    return -1;
+
+  length = *(uint16_t*)req->arg_ptr;
+  if (length != len) return -1; // safety check
+
+  memcpy(data, req->arg_ptr + 2, length);
+  req->arg_ptr += (length+5)&~3; // round up to multiple of 4
+
+  req->arg_num ++;
+  return 0;
+}
+
+// Skip the next argument
+void EspLink::cmdSkipArg(CmdRequest *req) {
+  uint16_t length;
+
+  if (req->arg_num >= req->cmd->argc) return;
+
+  length = *(uint16_t*)req->arg_ptr;
+
+  req->arg_ptr += (length+5)&~3;
+  req->arg_num ++;
+}
+
+// Return the length of the next argument
+uint16_t EspLink::cmdArgLen(CmdRequest *req) {
+  return *(uint16_t*)req->arg_ptr;
+}
+
diff --git a/arduino/libraries/EspLink/EspLink.h b/arduino/libraries/EspLink/EspLink.h
new file mode 100644
index 0000000..aff43f9
--- /dev/null
+++ b/arduino/libraries/EspLink/EspLink.h
@@ -0,0 +1,91 @@
+#ifndef ESP_LINK_H
+#define ESP_LINK_H
+
+#include <inttypes.h>
+#include <Stream.h>
+
+typedef struct __attribute__((__packed__)) {
+  uint16_t  len;      // length of data
+  uint8_t   data[0];  // really data[len]
+} CmdArg;
+
+typedef struct __attribute__((__packed__)) {
+  uint16_t  cmd;      // command to perform, from CmdName enum
+  uint16_t  argc;     // number of arguments to command
+  uint32_t  value;    // callback pointer for response or first argument
+  CmdArg    args[0];  // really args[argc]
+} CmdPacket;
+
+typedef struct {
+  CmdPacket *cmd;     // command packet header
+  uint32_t  arg_num;  // number of args parsed
+  uint8_t   *arg_ptr; // pointer to ??
+} CmdRequest;
+
+typedef void (* CmdRequestCB)(CmdRequest *);
+
+typedef enum {
+  CMD_NULL = 0,
+  CMD_SYNC,           // synchronize and clear
+  CMD_RESP_V,         // response with a value
+  CMD_RESP_CB,        // response with a callback
+  CMD_WIFI_STATUS,    // get the current wifi status
+  CMD_CB_ADD,
+  CMD_CB_EVENTS,
+  CMD_GET_TIME,       // get current time in seconds since the unix epoch
+
+  CMD_MQTT_SETUP = 10,  // set-up callbacks
+  CMD_MQTT_PUBLISH,     // publish a message
+  CMD_MQTT_SUBSCRIBE,   // subscribe to a topic
+  CMD_MQTT_LWT,         // set the last-will-topic and messge
+
+  CMD_REST_SETUP = 20,
+  CMD_REST_REQUEST,
+  CMD_REST_SETHEADER,
+  
+  CMD_WEB_DATA = 30,
+  CMD_WEB_REQ_CB,
+} CmdName;
+
+typedef enum
+{
+  WAIT_FOR_SLIP_START,
+  READ_SLIP_PACKAGE,
+} ReadState;
+
+class EspLink
+{
+  private:
+    uint16_t     crc16_out;
+    Stream      &stream;
+    ReadState    readState;
+    uint8_t  *   readBuf;
+    uint16_t     readBufPtr;
+    uint16_t     readBufMax;
+    int          readLastChar;
+    CmdRequestCB requestCb;
+
+    void crc16_add(uint8_t b, uint16_t *crc);
+    void writeChar(uint8_t chr);
+    void writeBuf(uint8_t * buf, uint16_t len);
+    void checkPacket();
+    void parseSlipPacket();
+
+  public:
+    EspLink(Stream &stream, CmdRequestCB callback);
+    ~EspLink();
+
+    void sendPacketStart(uint16_t cmd, uint32_t value, uint16_t argc);
+    void sendPacketArg(uint16_t len, uint8_t * data);
+    void sendPacketEnd();
+
+    void readLoop();
+
+    uint32_t cmdGetArgc(CmdRequest *req);
+    int32_t  cmdPopArg(CmdRequest *req, void *data, uint16_t len);
+    void     cmdSkipArg(CmdRequest *req);
+    uint16_t cmdArgLen(CmdRequest *req);
+};
+
+#endif /* ESP_LINK_H */
+
diff --git a/arduino/libraries/EspLink/WebServer.cpp b/arduino/libraries/EspLink/WebServer.cpp
new file mode 100644
index 0000000..6a5c270
--- /dev/null
+++ b/arduino/libraries/EspLink/WebServer.cpp
@@ -0,0 +1,214 @@
+#include "WebServer.h"
+#include "Arduino.h"
+
+#define RESUBSCRIBE_LIMIT 1000
+
+WebServer  * WebServer::instance = NULL;
+
+void webServerCallback(CmdRequest *req)
+{
+  WebServer::getInstance()->handleRequest(req);
+}
+
+WebServer::WebServer(Stream &streamIn, const WebMethod * PROGMEM methodsIn):espLink(streamIn, webServerCallback),methods(methodsIn),stream(streamIn),esplink_cb(NULL)
+{
+  instance = this;
+}
+
+void WebServer::init()
+{
+  registerCallback();
+}
+
+void WebServer::loop()
+{
+  // resubscribe periodically
+  uint32_t elapsed = millis() - last_connect_ts;
+  if( elapsed > RESUBSCRIBE_LIMIT )
+    registerCallback();
+  espLink.readLoop();
+}
+
+void WebServer::registerCallback()
+{
+  espLink.sendPacketStart(CMD_CB_ADD, 100, 1);
+  espLink.sendPacketArg(5, (uint8_t *)"webCb");
+  espLink.sendPacketEnd();
+  last_connect_ts = millis();
+}
+
+void WebServer::invokeMethod(RequestReason reason, WebMethod * method, CmdRequest *req)
+{
+  switch(reason)
+  {
+    case WS_BUTTON:
+      {
+        uint16_t len = espLink.cmdArgLen(req);
+        char bf[len+1];
+        bf[len] = 0;
+        espLink.cmdPopArg(req, bf, len);
+
+        method->callback(BUTTON_PRESS, bf, len);
+      }
+      break;
+    case WS_SUBMIT:
+      {
+        int arg_len = espLink.cmdGetArgc( req );
+        int cnt = 4;
+
+        while( cnt < arg_len )
+        {
+          uint16_t len = espLink.cmdArgLen(req);
+          char bf[len+1];
+          bf[len] = 0;
+          espLink.cmdPopArg(req, bf, len);
+
+          value_ptr = bf + 2 + strlen(bf+1);
+          method->callback(SET_FIELD, bf+1, strlen(bf+1));
+          
+          cnt++;
+        }
+      }
+      return;
+    case WS_LOAD:
+    case WS_REFRESH:
+      break;
+    default:
+      return;
+  }
+
+  espLink.sendPacketStart(CMD_WEB_DATA, 100, 255);
+  espLink.sendPacketArg(4, remote_ip);
+  espLink.sendPacketArg(2, (uint8_t *)&remote_port);
+
+  method->callback( reason == WS_LOAD ? LOAD : REFRESH, NULL, 0);
+
+  espLink.sendPacketArg(0, NULL);
+  espLink.sendPacketEnd();
+}
+
+void WebServer::handleRequest(CmdRequest *req)
+{
+  if( req->cmd->cmd != CMD_WEB_REQ_CB )
+  {
+    if( esplink_cb != NULL )
+      esplink_cb(req);
+    return;
+  }
+
+  uint16_t shrt;
+  espLink.cmdPopArg(req, &shrt, 2);
+  RequestReason reason = (RequestReason)shrt;
+
+  espLink.cmdPopArg(req, &remote_ip, 4);
+  espLink.cmdPopArg(req, &remote_port, 2);
+
+  {
+    uint16_t len = espLink.cmdArgLen(req);
+    char bf[len+1];
+    bf[len] = 0;
+    espLink.cmdPopArg(req, bf, len);
+
+    const WebMethod * meth = methods;
+    do
+    {
+      WebMethod m;
+      memcpy_P(&m, meth, sizeof(WebMethod));
+      if( m.url == NULL || m.callback == NULL )
+        break;
+
+      if( strcmp_P(bf, m.url) == 0 )
+      {
+        invokeMethod(reason, &m, req);
+        return;
+      }
+      meth++;
+    }while(1);
+  }
+
+  if( reason == WS_SUBMIT )
+    return;
+
+  // empty response
+  espLink.sendPacketStart(CMD_WEB_DATA, 100, 2);
+  espLink.sendPacketArg(4, remote_ip);
+  espLink.sendPacketArg(2, (uint8_t *)&remote_port);
+  espLink.sendPacketEnd();
+}
+
+void WebServer::setArgString(const char * name, const char * value)
+{
+  uint8_t nlen = strlen(name);
+  uint8_t vlen = strlen(value);
+  char buf[nlen + vlen + 3];
+  buf[0] = WEB_STRING;
+  strcpy(buf+1, name);
+  strcpy(buf+2+nlen, value);
+  espLink.sendPacketArg(nlen+vlen+2, (uint8_t *)buf);
+}
+
+void WebServer::setArgStringP(const char * name, const char * value)
+{
+  uint8_t nlen = strlen(name);
+  uint8_t vlen = strlen_P(value);
+  char buf[nlen + vlen + 3];
+  buf[0] = WEB_STRING;
+  strcpy(buf+1, name);
+  strcpy_P(buf+2+nlen, value);
+  espLink.sendPacketArg(nlen+vlen+2, (uint8_t *)buf);
+}
+
+void WebServer::setArgBoolean(const char * name, uint8_t value)
+{
+  uint8_t nlen = strlen(name);
+  char buf[nlen + 4];
+  buf[0] = WEB_BOOLEAN;
+  strcpy(buf+1, name);
+  buf[2 + nlen] = value;
+  espLink.sendPacketArg(nlen+3, (uint8_t *)buf);
+}
+
+void WebServer::setArgJson(const char * name, const char * value)
+{
+  uint8_t nlen = strlen(name);
+  uint8_t vlen = strlen(value);
+  char buf[nlen + vlen + 3];
+  buf[0] = WEB_JSON;
+  strcpy(buf+1, name);
+  strcpy(buf+2+nlen, value);
+  espLink.sendPacketArg(nlen+vlen+2, (uint8_t *)buf);
+}
+
+void WebServer::setArgInt(const char * name, int32_t value)
+{
+  uint8_t nlen = strlen(name);
+  char buf[nlen + 7];
+  buf[0] = WEB_INTEGER;
+  strcpy(buf+1, name);
+  memcpy(buf+2+nlen, &value, 4);
+  espLink.sendPacketArg(nlen+6, (uint8_t *)buf);
+}
+
+int32_t WebServer::getArgInt()
+{
+  return (int32_t)atol(value_ptr);
+}
+
+char * WebServer::getArgString()
+{
+  return value_ptr;
+}
+
+uint8_t WebServer::getArgBoolean()
+{
+  if( strcmp_P(value_ptr, PSTR("on")) == 0 )
+    return 1;
+  if( strcmp_P(value_ptr, PSTR("true")) == 0 )
+    return 1;
+  if( strcmp_P(value_ptr, PSTR("yes")) == 0 )
+    return 1;
+  if( strcmp_P(value_ptr, PSTR("1")) == 0 )
+    return 1;
+  return 0;
+}
+
diff --git a/arduino/libraries/EspLink/WebServer.h b/arduino/libraries/EspLink/WebServer.h
new file mode 100644
index 0000000..59f1cb2
--- /dev/null
+++ b/arduino/libraries/EspLink/WebServer.h
@@ -0,0 +1,91 @@
+#ifndef WEB_SERVER_H
+#define WEB_SERVER_H
+
+#include "EspLink.h"
+
+typedef enum
+{
+  BUTTON_PRESS,
+  SET_FIELD,
+  REFRESH,
+  LOAD,
+} WebServerCommand;
+
+typedef void (*WebServerCallback)(WebServerCommand command, char * data, int dataLen);
+
+typedef struct
+{
+  const char *  PROGMEM  url;
+  WebServerCallback      callback;
+} WebMethod;
+
+
+typedef enum {
+  WS_LOAD=0,
+  WS_REFRESH,
+  WS_BUTTON,
+  WS_SUBMIT,
+} RequestReason;
+
+typedef enum
+{
+  WEB_STRING=0,
+  WEB_NULL,
+  WEB_INTEGER,
+  WEB_BOOLEAN,
+  WEB_FLOAT,
+  WEB_JSON
+} WebValueType;
+
+class WebServer
+{
+  friend void webServerCallback(CmdRequest *req);
+  
+  private:
+    const WebMethod * PROGMEM methods;
+    Stream                   &stream;
+    static WebServer *        instance;
+
+    void                      invokeMethod(RequestReason reason, WebMethod * method, CmdRequest *req);
+    void                      handleRequest(CmdRequest *req);
+
+    uint8_t                   remote_ip[4];
+    uint16_t                  remote_port;
+
+    char *                    value_ptr;
+
+    uint32_t                  last_connect_ts;
+    
+    CmdRequestCB              esplink_cb;
+    
+  protected:
+    EspLink espLink;
+    
+  public:
+    WebServer(Stream &stream, const WebMethod * PROGMEM methods);
+
+    void init();
+    void loop();
+
+    void registerCallback();
+    
+    void setEspLinkCallback(CmdRequestCB cb) { esplink_cb = cb; }
+
+    static WebServer * getInstance() { return instance; }
+    uint8_t *          getRemoteIp() { return remote_ip; }
+    uint16_t           getRemotePort() { return remote_port; }
+
+    void               setArgInt(const char * name, int32_t value);
+    void               setArgJson(const char * name, const char * value);
+    void               setArgString(const char * name, const char * value);
+    void               setArgStringP(const char * name, const char * value);
+    void               setArgBoolean(const char * name, uint8_t value);
+
+    int32_t            getArgInt();
+    char *             getArgString();
+    uint8_t            getArgBoolean();
+    
+    EspLink *          getEspLink() { return &espLink; }
+};
+
+#endif /* WEB_SERVER_H */
diff --git a/arduino/libraries/EspLink/examples/EspLinkWebApp/EspLinkWebApp.ino b/arduino/libraries/EspLink/examples/EspLinkWebApp/EspLinkWebApp.ino
new file mode 100644
index 0000000..3f6dbaf
--- /dev/null
+++ b/arduino/libraries/EspLink/examples/EspLinkWebApp/EspLinkWebApp.ino
@@ -0,0 +1,35 @@
+#include "EspLink.h"
+#include "WebServer.h"
+#include "Pages.h"
+
+const char ledURL[] PROGMEM = "/LED.html.json";
+const char userURL[] PROGMEM = "/User.html.json";
+const char voltageURL[] PROGMEM = "/Voltage.html.json";
+
+const WebMethod PROGMEM methods[] = {
+  { ledURL, ledHtmlCallback },
+  { userURL, userHtmlCallback },
+  { voltageURL, voltageHtmlCallback },
+  { NULL, NULL },
+};
+
+WebServer webServer(Serial, methods);
+
+void setup()
+{
+  Serial.begin(57600);
+  webServer.init();
+
+  ledInit();
+  userInit();
+  voltageInit();
+}
+
+void loop()
+{
+  webServer.loop();
+
+  ledLoop();
+  voltageLoop();
+}
+
diff --git a/arduino/libraries/EspLink/examples/EspLinkWebApp/LedPage.ino b/arduino/libraries/EspLink/examples/EspLinkWebApp/LedPage.ino
new file mode 100644
index 0000000..494df83
--- /dev/null
+++ b/arduino/libraries/EspLink/examples/EspLinkWebApp/LedPage.ino
@@ -0,0 +1,188 @@
+#include "WebServer.h"
+
+#define LED_PIN  13
+
+int8_t  blinking = 0;
+int8_t  frequency = 10;
+uint8_t pattern = 2;
+uint16_t elapse = 100;
+uint16_t elapse_delta = 200;
+uint32_t next_ts = 0;
+
+#define MAX_LOGS 5
+uint32_t log_ts[MAX_LOGS];
+uint8_t  log_msg[MAX_LOGS];
+uint8_t  log_ptr = 0;
+
+void ledInit()
+{
+  pinMode(LED_PIN, OUTPUT);
+  digitalWrite(LED_PIN, false);
+}
+
+void ledLoop()
+{ 
+  if( blinking )
+  {
+    if( next_ts <= millis() )
+    {
+      digitalWrite(LED_PIN, !digitalRead(LED_PIN));
+      next_ts += elapse;
+      elapse = elapse_delta - elapse;
+    }
+  }
+}
+
+void ledAddLog(uint8_t msg)
+{
+  if( log_ptr >= MAX_LOGS )
+    log_ptr = MAX_LOGS - 1;
+
+  for(int8_t i=log_ptr-1; i >= 0; i--)
+  {
+    log_ts[i+1] = log_ts[i];
+    log_msg[i+1] = log_msg[i];
+  }
+  log_msg[0] = msg;
+  log_ts[0] = millis();
+  log_ptr++;
+}
+
+void ledHistoryToLog(char * buf)
+{
+  buf[0] = 0;
+  strcat(buf, "[");
+  for(uint8_t i=0; i < log_ptr; i++)
+  {
+    if( i != 0 )
+      strcat(buf, ",");
+    
+    char bf[20];
+    sprintf(bf, "\"%lds: ", log_ts[i] / 1000);
+    strcat(buf, bf);
+
+    uint8_t msg = log_msg[i];
+    if( msg == 0xE1 )
+    {
+      strcat_P(buf, PSTR("set pattern to 25%-75%"));
+    }
+    else if( msg == 0xE2 )
+    {
+      strcat_P(buf, PSTR("set pattern to 50%-50%"));
+    }
+    else if( msg == 0xE3 )
+    {
+      strcat_P(buf, PSTR("set pattern to 75%-25%"));
+    }
+    else if( msg == 0xF0 )
+    {
+      strcat_P(buf, PSTR("set led on"));
+    }
+    else if( msg == 0xF1 )
+    {
+      strcat_P(buf, PSTR("set led blinking"));
+    }
+    else if( msg == 0xF2 )
+    {
+      strcat_P(buf, PSTR("set led off"));
+    }
+    else
+    {
+      strcat_P(buf, PSTR("set frequency to "));
+      sprintf(bf, "%d Hz", msg);
+      strcat(buf, bf);
+    }
+    strcat(buf, "\"");
+  }
+  strcat(buf, "]");
+}
+
+
+void ledHtmlCallback(WebServerCommand command, char * data, int dataLen)
+{
+  switch(command)
+  {
+    case BUTTON_PRESS:
+      if( strcmp_P(data, PSTR("btn_on") ) == 0 )
+      {
+        if( blinking || digitalRead(LED_PIN) == false )
+          ledAddLog(0xF0);
+        blinking = 0;
+        digitalWrite(LED_PIN, true);
+      } else if( strcmp_P(data, PSTR("btn_off") ) == 0 )
+      {
+        if( blinking || digitalRead(LED_PIN) == true )
+          ledAddLog(0xF2);
+        blinking = 0;
+        digitalWrite(LED_PIN, false);
+      } else if( strcmp_P(data, PSTR("btn_blink") ) == 0 )
+      {
+        if( !blinking )
+          ledAddLog(0xF1);
+        blinking = 1;
+        next_ts = millis() + elapse;
+      }
+      break;
+    case SET_FIELD:
+      if( strcmp_P(data, PSTR("frequency") ) == 0 )
+      {
+        int8_t oldf = frequency;
+        frequency = webServer.getArgInt();
+        digitalWrite(LED_PIN, false);
+        elapse_delta = 2000 / frequency;
+        elapse = pattern * elapse_delta / 4;
+        if( oldf != frequency )
+          ledAddLog(frequency);
+      }
+      else if( strcmp_P(data, PSTR("pattern") ) == 0 )
+      {
+        int8_t oldp = pattern;
+        char * arg = webServer.getArgString();
+
+        if( strcmp_P(arg, PSTR("25_75")) == 0 )
+          pattern = 1;
+        else if( strcmp_P(arg, PSTR("50_50")) == 0 )
+          pattern = 2;
+        else if( strcmp_P(arg, PSTR("75_25")) == 0 )
+          pattern = 3;
+
+        digitalWrite(LED_PIN, false);
+        elapse = pattern * elapse_delta / 4;
+
+        if( oldp != pattern )
+          ledAddLog(0xE0 + pattern);
+      }
+      break;
+    case LOAD:
+      webServer.setArgInt("frequency", frequency);
+
+      switch(pattern)
+      {
+        case 1:
+          webServer.setArgStringP("pattern", PSTR("25_75"));
+          break;
+        case 2:
+          webServer.setArgStringP("pattern", PSTR("50_50"));
+          break;
+        case 3:
+          webServer.setArgStringP("pattern", PSTR("75_25"));
+          break;
+      }
+    case REFRESH:
+      {
+        if( blinking )
+          webServer.setArgStringP("text", PSTR("LED is blinking"));
+        else
+          webServer.setArgStringP("text", digitalRead(LED_PIN) ? PSTR("LED is turned on") : PSTR("LED is turned off"));
+
+        char buf[255];
+        ledHistoryToLog(buf);
+        webServer.setArgJson("led_history", buf);
+      }
+      break;
+    default:
+      break;
+  }
+}
+
+
diff --git a/arduino/libraries/EspLink/examples/EspLinkWebApp/Makefile.webpage b/arduino/libraries/EspLink/examples/EspLinkWebApp/Makefile.webpage
new file mode 100644
index 0000000..d0183b0
--- /dev/null
+++ b/arduino/libraries/EspLink/examples/EspLinkWebApp/Makefile.webpage
@@ -0,0 +1,8 @@
+all: user_img
+
+clean:
+	rm -rf web-page.espfs.img
+
+user_img:
+	../../../../../createEspFs.pl web-page web-page.espfs.img
+
diff --git a/arduino/libraries/EspLink/examples/EspLinkWebApp/Pages.h b/arduino/libraries/EspLink/examples/EspLinkWebApp/Pages.h
new file mode 100644
index 0000000..7043b9d
--- /dev/null
+++ b/arduino/libraries/EspLink/examples/EspLinkWebApp/Pages.h
@@ -0,0 +1,17 @@
+#ifndef PAGES_H
+#define PAGES_H
+
+void ledHtmlCallback(WebServerCommand command, char * data, int dataLen);
+void ledLoop();
+void ledInit();
+
+void userHtmlCallback(WebServerCommand command, char * data, int dataLen);
+void userInit();
+
+void voltageHtmlCallback(WebServerCommand command, char * data, int dataLen);
+void voltageLoop();
+void voltageInit();
+
+#endif /* PAGES_H */
+
+
diff --git a/arduino/libraries/EspLink/examples/EspLinkWebApp/UserPage.ino b/arduino/libraries/EspLink/examples/EspLinkWebApp/UserPage.ino
new file mode 100644
index 0000000..e6581a5
--- /dev/null
+++ b/arduino/libraries/EspLink/examples/EspLinkWebApp/UserPage.ino
@@ -0,0 +1,84 @@
+#include <EEPROM.h>
+#include "WebServer.h"
+
+#define MAGIC 0xABEF
+
+#define MAX_STR_LEN  32
+
+#define POS_MAGIC 0
+#define POS_FIRST_NAME (POS_MAGIC + 2)
+#define POS_LAST_NAME (POS_FIRST_NAME + MAX_STR_LEN)
+#define POS_AGE (POS_LAST_NAME + MAX_STR_LEN)
+#define POS_GENDER (POS_AGE+1)
+#define POS_NOTIFICATIONS (POS_GENDER+1)
+
+void userInit()
+{
+  uint16_t magic;
+  EEPROM.get(POS_MAGIC, magic);
+
+  if( magic != MAGIC )
+  {
+    magic = MAGIC;
+    EEPROM.put(POS_MAGIC, magic);
+    EEPROM.update(POS_FIRST_NAME, 0);
+    EEPROM.update(POS_LAST_NAME, 0);
+    EEPROM.update(POS_AGE, 0);
+    EEPROM.update(POS_GENDER, 'f');
+    EEPROM.update(POS_NOTIFICATIONS, 0);
+  }
+}
+
+void userWriteStr(char * str, int ndx)
+{
+  for(uint8_t i=0; i < MAX_STR_LEN-1; i++)
+  {
+    EEPROM.update(ndx + i, str[i]);
+    if( str[i] == 0 )
+      break;
+  }
+  EEPROM.update(ndx + MAX_STR_LEN - 1, 0);
+}
+
+void userReadStr(char * str, int ndx)
+{
+  for(uint8_t i=0; i < MAX_STR_LEN; i++)
+  {
+    str[i] = EEPROM[ndx + i];
+  }
+}
+
+void userHtmlCallback(WebServerCommand command, char * data, int dataLen)
+{
+  switch(command)
+  {
+    case SET_FIELD:
+      if( strcmp_P(data, PSTR("first_name")) == 0 )
+        userWriteStr(webServer.getArgString(), POS_FIRST_NAME);
+      if( strcmp_P(data, PSTR("last_name")) == 0 )
+        userWriteStr(webServer.getArgString(), POS_LAST_NAME);
+      if( strcmp_P(data, PSTR("age")) == 0 )
+        EEPROM.update(POS_AGE, (uint8_t)webServer.getArgInt());
+      if( strcmp_P(data, PSTR("gender")) == 0 )
+        EEPROM.update(POS_GENDER, (strcmp_P(webServer.getArgString(), PSTR("male")) == 0 ? 'm' : 'f'));
+      if( strcmp_P(data, PSTR("notifications")) == 0 )
+        EEPROM.update(POS_NOTIFICATIONS, (uint8_t)webServer.getArgBoolean());
+      break;
+    case LOAD:
+      {
+        char buf[MAX_STR_LEN];
+        userReadStr( buf, POS_FIRST_NAME );
+        webServer.setArgString("first_name", buf);
+        userReadStr( buf, POS_LAST_NAME );
+        webServer.setArgString("last_name", buf);
+        webServer.setArgInt("age", (uint8_t)EEPROM[POS_AGE]);
+        webServer.setArgStringP("gender", (EEPROM[POS_GENDER] == 'm') ? PSTR("male") : PSTR("female"));
+        webServer.setArgBoolean("notifications", EEPROM[POS_NOTIFICATIONS] != 0);
+      }
+      break;
+    case REFRESH:
+      // do nothing
+      break;
+  }
+}
+
diff --git a/arduino/libraries/EspLink/examples/EspLinkWebApp/VoltagePage.ino b/arduino/libraries/EspLink/examples/EspLinkWebApp/VoltagePage.ino
new file mode 100644
index 0000000..4080f75
--- /dev/null
+++ b/arduino/libraries/EspLink/examples/EspLinkWebApp/VoltagePage.ino
@@ -0,0 +1,125 @@
+#include "WebServer.h"
+
+#include <avr/io.h>
+
+#define SAMPLE_COUNT 100
+#define PERIOD_COUNT (135 * SAMPLE_COUNT)
+
+uint16_t smin = 0xFFFF;
+uint16_t smax = 0;
+uint32_t savg = 0;
+
+uint16_t count;
+uint32_t voltage = 0;
+uint16_t measured_voltage = 0;
+
+#define MAX_HISTORY 3
+
+uint8_t history_cnt = 0;
+uint32_t h_ts[MAX_HISTORY];
+uint16_t h_min[MAX_HISTORY];
+uint16_t h_max[MAX_HISTORY];
+uint16_t h_avg[MAX_HISTORY];
+
+uint16_t calibrate = 0x128; // calibrate this manually
+
+void voltageInit()
+{
+  analogReference(DEFAULT);
+
+  count = 0;
+}
+
+void voltageLoop()
+{
+  uint16_t adc = analogRead(A0);    
+
+  if( adc < smin )
+    smin = adc;
+  if( adc > smax )
+    smax = adc;
+  savg += adc;
+  
+  voltage += adc;
+  count++;
+
+  if( (count % SAMPLE_COUNT) == 0 )
+  {
+    voltage /= SAMPLE_COUNT;
+    measured_voltage = voltage * calibrate / 256;
+    voltage = 0;
+  }
+  if( count == PERIOD_COUNT )
+  {
+    for(int8_t i=MAX_HISTORY-2; i >=0; i-- )
+    {
+      h_ts[i+1] = h_ts[i];
+      h_min[i+1] = h_min[i];
+      h_max[i+1] = h_max[i];
+      h_avg[i+1] = h_avg[i];
+    }
+
+    h_ts[0] = millis();
+    h_min[0] = (uint32_t)smin * calibrate / 256;
+    h_max[0] = (uint32_t)smax * calibrate / 256;
+    h_avg[0] = (savg / PERIOD_COUNT) * calibrate / 256;
+
+    smin = 0xFFFF;
+    smax = 0;
+    savg = 0;
+
+    if( history_cnt < MAX_HISTORY )
+      history_cnt++;
+    count = 0;
+  }
+}
+
+void voltageHtmlCallback(WebServerCommand command, char * data, int dataLen)
+{
+  switch(command)
+  {
+    case BUTTON_PRESS:
+      // no buttons
+      break;   
+    case SET_FIELD:
+      /* TODO */
+      break;
+    case LOAD:
+    case REFRESH:
+      {
+        char buf[20];
+        uint8_t int_part = measured_voltage / 256;
+        uint8_t float_part = ((measured_voltage & 255) * 100) / 256;
+        sprintf(buf, "%d.%02d V", int_part, float_part);
+        webServer.setArgString("voltage", buf);
+
+        char tab[256];
+        tab[0] = 0;
+        strcat_P(tab, PSTR("[[\"Time\",\"Min\",\"AVG\",\"Max\"]"));
+
+        for(uint8_t i=0; i < history_cnt; i++ )
+        {
+          uint8_t min_i = h_min[i] / 256;
+          uint8_t min_f = ((h_min[i] & 255) * 100) / 256;
+          uint8_t max_i = h_max[i] / 256;
+          uint8_t max_f = ((h_max[i] & 255) * 100) / 256;
+          uint8_t avg_i = h_avg[i] / 256;
+          uint8_t avg_f = ((h_avg[i] & 255) * 100) / 256;
+
+          sprintf(buf, ",[\"%d s\",", h_ts[i] / 1000);
+          strcat(tab, buf);
+          sprintf(buf, "\"%d.%02d V\",", min_i, min_f);
+          strcat(tab, buf);
+          sprintf(buf, "\"%d.%02d V\",", avg_i, avg_f);
+          strcat(tab, buf);
+          sprintf(buf, "\"%d.%02d V\"]", max_i, max_f);
+          strcat(tab, buf);
+        }
+
+        strcat_P(tab, PSTR("]"));
+        webServer.setArgJson("table", tab);
+      }
+      break;
+  }
+}
+
diff --git a/arduino/libraries/EspLink/examples/EspLinkWebApp/web-page.espfs.img b/arduino/libraries/EspLink/examples/EspLinkWebApp/web-page.espfs.img
new file mode 100644
index 0000000..e7a760f
Binary files /dev/null and b/arduino/libraries/EspLink/examples/EspLinkWebApp/web-page.espfs.img differ
diff --git a/arduino/libraries/EspLink/examples/EspLinkWebApp/web-page/LED.html b/arduino/libraries/EspLink/examples/EspLinkWebApp/web-page/LED.html
new file mode 100644
index 0000000..a87f348
--- /dev/null
+++ b/arduino/libraries/EspLink/examples/EspLinkWebApp/web-page/LED.html
@@ -0,0 +1,36 @@
+  <!-- EspLink will add header here -->
+  
+  <div class="header">
+    <h1>LED configuration</h1>
+  </div>
+
+  <div class="content">
+    <div class="pure-g"><div class="pure-u-1 pure-u-md-1-2">
+      <div class="card">
+        <h1>Control</h1>
+        <button id="btn_on" type="button">Turn on</button>
+        <button id="btn_blink" type="button">Start blinking</button>
+        <button id="btn_off" type="button">Turn off</button>
+        <p id="text"/>
+      </div>
+      <div class="card">
+        <h1>Frequency and pattern</h1>
+        <form>
+          <b>Pattern:</b><br/>
+          <input type="radio" name="pattern" value="25_75">25% on 75% off</input><br/>
+          <input type="radio" name="pattern" value="50_50">50% on 50% off</input><br/>
+          <input type="radio" name="pattern" value="75_25">75% on 25% off</input><br/>
+        
+          <b>Frequency:</b><br/>
+          <input type="range" name="frequency" min="1" max="25"><br/>
+          <input type="submit">
+        </form>
+      </div></div>
+      <div class="pure-u-1 pure-u-md-1-2">
+      <div class="card" style="min-height: 400px">
+        <h1>Logs</h1>
+        <ul id="led_history"/>
+      </div>      
+    </div></div>
+  </div>
+</body></html>
diff --git a/arduino/libraries/EspLink/examples/EspLinkWebApp/web-page/User.html b/arduino/libraries/EspLink/examples/EspLinkWebApp/web-page/User.html
new file mode 100644
index 0000000..8dc4286
--- /dev/null
+++ b/arduino/libraries/EspLink/examples/EspLinkWebApp/web-page/User.html
@@ -0,0 +1,24 @@
+  <!-- EspLink will add header here -->
+  
+  <div class="header">
+    <h1>User setup</h1>
+  </div>
+
+  <div class="content">
+    <form>
+      First name:<br/><input name="first_name" type="text"/>
+      Last name:<br/><input name="last_name" type="text"/>
+      Age:
+      <input name="age" type="number"/>
+      Gender:
+      <select name="gender">
+        <option value="female">Female</option>
+        <option value="male">Male</option>
+      </select>
+      <br>
+      Notifications<input name="notifications" type="checkbox"/>
+      <br>
+      <input type="submit">
+    </form>
+  </div>
+</body></html>
diff --git a/arduino/libraries/EspLink/examples/EspLinkWebApp/web-page/Voltage.html b/arduino/libraries/EspLink/examples/EspLinkWebApp/web-page/Voltage.html
new file mode 100644
index 0000000..b52098e
--- /dev/null
+++ b/arduino/libraries/EspLink/examples/EspLinkWebApp/web-page/Voltage.html
@@ -0,0 +1,15 @@
+  <!-- EspLink will add header here -->
+  
+  <meta name="refresh-rate" content="500" />
+  
+  <div class="header">
+    <h1>Voltage measurement</h1>
+  </div>
+
+  <div class="content">
+    <p id="voltage" align="center" style="font-size: 800%"/>
+
+    <table class="pure-table pure-table-bordered" align="center" id="table"/>
+  </div>
+  
+</body></html>
diff --git a/arduino/libraries/EspLink/examples/EspLinkWebSimpleLedControl/EspLinkWebSimpleLedControl.ino b/arduino/libraries/EspLink/examples/EspLinkWebSimpleLedControl/EspLinkWebSimpleLedControl.ino
new file mode 100644
index 0000000..516a2ae
--- /dev/null
+++ b/arduino/libraries/EspLink/examples/EspLinkWebSimpleLedControl/EspLinkWebSimpleLedControl.ino
@@ -0,0 +1,49 @@
+#include "EspLink.h"
+#include "WebServer.h"
+
+#define LED_PIN 13
+
+void simpleLedHtmlCallback(WebServerCommand command, char * data, int dataLen);
+const char simpleLedURL[] PROGMEM = "/SimpleLED.html.json";
+
+const WebMethod PROGMEM methods[] = {
+  { simpleLedURL, simpleLedHtmlCallback },
+  { NULL, NULL },
+};
+
+WebServer webServer(Serial, methods);
+
+void simpleLedHtmlCallback(WebServerCommand command, char * data, int dataLen)
+{
+  switch(command)
+  {
+    case BUTTON_PRESS:
+      if( strcmp_P(data, PSTR("btn_on") ) == 0 )
+        digitalWrite(LED_PIN, true);
+      else if( strcmp_P(data, PSTR("btn_off") ) == 0 )
+        digitalWrite(LED_PIN, false);
+      break;
+    case SET_FIELD:
+      // no fields to set
+      break;
+    case LOAD:
+    case REFRESH:
+      if( digitalRead(LED_PIN) )
+        webServer.setArgString("text", "LED is on");
+      else
+        webServer.setArgString("text", "LED is off");
+      break;
+  }
+}
+
+void setup()
+{
+  Serial.begin(57600);
+  webServer.init();
+}
+
+void loop()
+{
+  webServer.loop();
+}
+
diff --git a/arduino/libraries/EspLink/examples/EspLinkWebSimpleLedControl/SimpleLED.html b/arduino/libraries/EspLink/examples/EspLinkWebSimpleLedControl/SimpleLED.html
new file mode 100644
index 0000000..27dc359
--- /dev/null
+++ b/arduino/libraries/EspLink/examples/EspLinkWebSimpleLedControl/SimpleLED.html
@@ -0,0 +1,7 @@
+  <!-- EspLink will add header here -->
+  
+  <h1 class="header">Simple LED control</h1>
+  <h2><div id="text"/></h2>
+  <button id="btn_on" type="button">Turn on</button>
+  <button id="btn_off" type="button">Turn off</button>
+</body></html>
diff --git a/arduino/libraries/readme.txt b/arduino/libraries/readme.txt
new file mode 100644
index 0000000..96ce674
--- /dev/null
+++ b/arduino/libraries/readme.txt
@@ -0,0 +1 @@
+For information on installing libraries, see: http://www.arduino.cc/en/Guide/Libraries
diff --git a/cmd/cmd.h b/cmd/cmd.h
index 6b4b018..be1e684 100644
--- a/cmd/cmd.h
+++ b/cmd/cmd.h
@@ -48,6 +48,9 @@ typedef enum {
   CMD_REST_SETUP = 20,
   CMD_REST_REQUEST,
   CMD_REST_SETHEADER,
+  
+  CMD_WEB_DATA = 30,  // MCU pushes data using this command
+  CMD_WEB_REQ_CB,     // esp-link WEB callback
 } CmdName;
 
 typedef void (*cmdfunc_t)(CmdPacket *cmd);
diff --git a/cmd/handlers.c b/cmd/handlers.c
index 9e719a7..af328e7 100644
--- a/cmd/handlers.c
+++ b/cmd/handlers.c
@@ -12,6 +12,7 @@
 #ifdef REST
 #include <rest.h>
 #endif
+#include <web-server.h>
 
 #ifdef CMD_DBG
 #define DBG(format, ...) do { os_printf(format, ## __VA_ARGS__); } while(0)
@@ -47,6 +48,7 @@ const CmdList commands[] = {
   {CMD_REST_REQUEST,    "REST_REQ",       REST_Request},
   {CMD_REST_SETHEADER,  "REST_SETHDR",    REST_SetHeader},
 #endif
+  {CMD_WEB_DATA,        "WEB_DATA",       WEB_Data},
 };
 
 //===== List of registered callbacks (to uC)
diff --git a/createEspFs.pl b/createEspFs.pl
new file mode 100755
index 0000000..1612098
--- /dev/null
+++ b/createEspFs.pl
@@ -0,0 +1,114 @@
+#!/usr/bin/perl
+
+use strict;
+use Data::Dumper;
+
+my $dir = shift @ARGV;
+my $out = shift @ARGV;
+
+my $espfs = '';
+
+my @structured = read_dir_structure($dir, "");
+
+for my $file (@structured)
+{
+  my $flags = 0;
+  my $name = $file;
+  my $compression = 0;
+  
+  if( $name =~ /\.gz$/ )
+  {
+    $flags |= 2;
+    $name =~ s/\.gz$//;
+  }
+
+  my $head = '<!doctype html><html><head><title>esp-link</title><link rel=stylesheet href="/pure.css"><link rel=stylesheet href="/style.css"><meta name=viewport content="width=device-width, initial-scale=1"><script src="/ui.js"></script><script src="/userpage.js"></script></head><body><div id=layout>';
+  
+  open IF, "<", "$dir/$file" or die "Can't read file: $!";
+  my @fc = <IF>;
+  close(IF);
+  my $cnt = join("", @fc);
+
+  if( $name =~ /\.html$/ )
+  {
+    if( ! ( $flags & 2 ) )
+    {
+      $cnt = "$head$cnt";
+    }
+    else
+    {
+      printf("TODO: prepend headers to GZipped HTML content!\n");
+    }
+  }
+  
+  $name .= chr(0);
+  $name .= chr(0) while( (length($name) & 3) != 0 );
+  
+  my $size = length($cnt);
+  
+  $espfs .= "ESfs";
+  $espfs .= chr($flags);
+  $espfs .= chr($compression);
+  $espfs .= chr( length($name) & 255 );
+  $espfs .= chr( length($name) / 256 );
+  $espfs .= chr( $size & 255 );
+  $espfs .= chr( ( $size / 0x100 ) & 255 );
+  $espfs .= chr( ( $size / 0x10000 ) & 255 );
+  $espfs .= chr( ( $size / 0x1000000 ) & 255 );
+  $espfs .= chr( $size & 255 );
+  $espfs .= chr( ( $size / 0x100 ) & 255 );
+  $espfs .= chr( ( $size / 0x10000 ) & 255 );
+  $espfs .= chr( ( $size / 0x1000000 ) & 255 );
+
+  $espfs .= $name;
+
+  
+  
+  $cnt .= chr(0) while( (length($cnt) & 3) != 0 );
+  $espfs .= $cnt;
+}
+
+$espfs .= "ESfs";
+$espfs .= chr(1);
+for(my $i=0; $i < 11; $i++)
+{
+  $espfs .= chr(0);
+}
+
+open FH, ">", $out or die "Can't open file for write, $!";
+print FH $espfs;
+close(FH);
+
+
+exit(0);
+
+sub read_dir_structure
+{
+  my ($dir, $base) = @_;
+
+  my @files;
+  
+  opendir my $dh, $dir or die "Could not open '$dir' for reading: $!\n";
+
+  while (my $file = readdir $dh) {
+    if ($file eq '.' or $file eq '..') {
+      next;
+    }
+
+    my $path = "$dir/$file";
+    if( -d "$path" )
+    {
+      my @sd = read_dir_structure($path, "$base/$file");
+      push @files, @sd ;
+    }
+    else
+    {
+      push @files, "$base/$file";
+    }
+  }
+
+  close( $dh );
+  
+  $_ =~ s/^\/// for(@files);
+  return @files;
+}
diff --git a/esp-link/cgi.c b/esp-link/cgi.c
index 96c03e9..76b1539 100644
--- a/esp-link/cgi.c
+++ b/esp-link/cgi.c
@@ -16,6 +16,7 @@ Some random cgi routines.
 #include <esp8266.h>
 #include "cgi.h"
 #include "config.h"
+#include "web-server.h"
 
 #ifdef CGI_DBG
 #define DBG(format, ...) do { os_printf(format, ## __VA_ARGS__); } while(0)
@@ -193,8 +194,7 @@ int ICACHE_FLASH_ATTR cgiMenu(HttpdConnData *connData) {
   if (connData->conn==NULL) return HTTPD_CGI_DONE; // Connection aborted. Clean up.
   char buff[1024];
   // don't use jsonHeader so the response does get cached
-  httpdStartResponse(connData, 200);
-  httpdHeader(connData, "Cache-Control", "max-age=3600, must-revalidate");
+  noCacheHeaders(connData, 200);
   httpdHeader(connData, "Content-Type", "application/json");
   httpdEndHeaders(connData);
   // limit hostname to 12 chars
@@ -213,12 +213,14 @@ int ICACHE_FLASH_ATTR cgiMenu(HttpdConnData *connData) {
 #ifdef MQTT
         "\"REST/MQTT\", \"/mqtt.html\", "
 #endif
-        "\"Debug log\", \"/log.html\""
+        "\"Debug log\", \"/log.html\", "
+        "\"Web Server\", \"/web-server.html\""
+	"%s"
       " ], "
       "\"version\": \"%s\", "
       "\"name\": \"%s\""
     " }",
-  esp_link_version, name);
+  WEB_UserPages(), esp_link_version, name);
 
   httpdSend(connData, buff, -1);
   return HTTPD_CGI_DONE;
diff --git a/esp-link/cgiservices.c b/esp-link/cgiservices.c
index 200039d..ef76287 100644
--- a/esp-link/cgiservices.c
+++ b/esp-link/cgiservices.c
@@ -68,6 +68,7 @@ int ICACHE_FLASH_ATTR cgiSystemInfo(HttpdConnData *connData) {
       "\"name\": \"%s\", "
       "\"reset cause\": \"%d=%s\", "
       "\"size\": \"%s\", "
+      "\"upload-size\": \"%d\", "
       "\"id\": \"0x%02X 0x%04X\", "
       "\"partition\": \"%s\", "
       "\"slip\": \"%s\", "
@@ -79,6 +80,7 @@ int ICACHE_FLASH_ATTR cgiSystemInfo(HttpdConnData *connData) {
     rst_info->reason,
     rst_codes[rst_info->reason],
     flash_maps[system_get_flash_size_map()],
+    getUserPageSectionEnd()-getUserPageSectionStart(),
     fid & 0xff, (fid & 0xff00) | ((fid >> 16) & 0xff),
     part_id ? "user2.bin" : "user1.bin",
     flashConfig.slip_enable ? "enabled" : "disabled",
diff --git a/esp-link/cgiwebserversetup.c b/esp-link/cgiwebserversetup.c
new file mode 100644
index 0000000..2a25950
--- /dev/null
+++ b/esp-link/cgiwebserversetup.c
@@ -0,0 +1,158 @@
+// Copyright (c) 2015 by Thorsten von Eicken, see LICENSE.txt in the esp-link repo
+
+#include <esp8266.h>
+#include <osapi.h>
+#include "cgi.h"
+#include "cgioptiboot.h"
+#include "multipart.h"
+#include "espfsformat.h"
+#include "config.h"
+#include "web-server.h"
+
+int upload_offset = 0;    // flash offset where to store page upload
+int html_header_len = 0;  // HTML header length (for uploading HTML files)
+
+// this is the header to add if user uploads HTML file
+const char * HTML_HEADER =   "<!doctype html><html><head><title>esp-link</title>"
+                             "<link rel=stylesheet href=\"/pure.css\"><link rel=stylesheet href=\"/style.css\">"
+                             "<meta name=viewport content=\"width=device-width, initial-scale=1\"><script src=\"/ui.js\">"
+                             "</script><script src=\"/userpage.js\"></script></head><body><div id=layout>    ";
+
+// multipart callback for uploading user defined pages
+int ICACHE_FLASH_ATTR webServerSetupMultipartCallback(MultipartCmd cmd, char *data, int dataLen, int position)
+{
+  switch(cmd)
+  {
+    case FILE_START:
+      upload_offset = 0;
+      html_header_len = 0;
+      // simple HTML file
+      if( ( dataLen > 5 ) && ( os_strcmp(data + dataLen - 5, ".html") == 0 ) ) // if the file ends with .html, wrap into an espfs image
+      {
+        // write the start block on esp-fs
+        int spi_flash_addr = getUserPageSectionStart();
+        spi_flash_erase_sector(spi_flash_addr/SPI_FLASH_SEC_SIZE);
+        EspFsHeader hdr;
+        hdr.magic = 0xFFFFFFFF; // espfs magic is invalid during upload
+        hdr.flags = 0;
+        hdr.compression = 0;
+        
+        int len = dataLen + 1;
+        while(( len & 3 ) != 0 )
+          len++;
+        
+        hdr.nameLen = len;
+        hdr.fileLenComp = hdr.fileLenDecomp = 0xFFFFFFFF;
+
+        spi_flash_write( spi_flash_addr + upload_offset, (uint32_t *)(&hdr), sizeof(EspFsHeader) );
+        upload_offset += sizeof(EspFsHeader);
+
+        char nameBuf[len];
+        os_memset(nameBuf, 0, len);
+        os_memcpy(nameBuf, data, dataLen);
+
+        spi_flash_write( spi_flash_addr + upload_offset, (uint32_t *)(nameBuf), len );
+        upload_offset += len;
+
+        html_header_len = os_strlen(HTML_HEADER) & ~3; // upload only 4 byte aligned part
+        char buf[html_header_len];
+        os_memcpy(buf, HTML_HEADER, html_header_len);
+        spi_flash_write( spi_flash_addr + upload_offset, (uint32_t *)(buf), html_header_len );
+        upload_offset += html_header_len;
+      }
+      break;
+    case FILE_DATA:
+      if(( position < 4 ) && (upload_offset == 0)) // for espfs images check the magic number
+      {
+        for(int p = position; p < 4; p++ )
+        {
+          if( data[p - position] != ((ESPFS_MAGIC >> (p * 8) ) & 255 ) )
+          {
+            os_printf("Not an espfs image!\n");
+            return 1;
+          }
+          data[p - position] = 0xFF;  // espfs magic is invalid during upload
+        }
+      }
+      
+      int spi_flash_addr = getUserPageSectionStart() + upload_offset + position;
+      int spi_flash_end_addr = spi_flash_addr + dataLen;
+      if( spi_flash_end_addr + dataLen >= getUserPageSectionEnd() )
+      {
+        os_printf("No more space in the flash!\n");
+        return 1;
+      }
+      
+      int ptr = 0;
+      while( spi_flash_addr < spi_flash_end_addr )
+      {
+        if (spi_flash_addr % SPI_FLASH_SEC_SIZE == 0){
+          spi_flash_erase_sector(spi_flash_addr/SPI_FLASH_SEC_SIZE);
+        }
+        
+        int max = (spi_flash_addr | (SPI_FLASH_SEC_SIZE - 1)) + 1;
+        int len = spi_flash_end_addr - spi_flash_addr;
+        if( spi_flash_end_addr > max )
+          len = max - spi_flash_addr;
+
+        spi_flash_write( spi_flash_addr, (uint32_t *)(data + ptr), len );
+        ptr += len;
+        spi_flash_addr += len;
+      }
+      
+      break;
+    case FILE_DONE:
+      {
+        if( html_header_len != 0 )
+        {
+          // write the terminating block on esp-fs
+          int spi_flash_addr = getUserPageSectionStart() + upload_offset + position;
+
+          uint32_t pad = 0;
+          uint8_t pad_cnt = (4 - position) & 3;
+          if( pad_cnt )
+            spi_flash_write( spi_flash_addr, &pad, pad_cnt );
+	  
+	  spi_flash_addr += pad_cnt;
+
+	  // create ESPFS image
+          EspFsHeader hdr;
+          hdr.magic = ESPFS_MAGIC; 
+          hdr.flags = 1;
+          hdr.compression = 0;
+          hdr.nameLen = 0;
+          hdr.fileLenComp = hdr.fileLenDecomp = 0;
+
+          spi_flash_write( spi_flash_addr, (uint32_t *)(&hdr), sizeof(EspFsHeader) );
+
+          uint32_t totallen = html_header_len + position;
+  
+	  // restore ESPFS magic
+          spi_flash_write( (int)getUserPageSectionStart(), (uint32_t *)&hdr.magic, sizeof(uint32_t) );
+	  // set file size
+          spi_flash_write( (int)getUserPageSectionStart() + 8, &totallen, sizeof(uint32_t) );
+          spi_flash_write( (int)getUserPageSectionStart() + 12, &totallen, sizeof(uint32_t) );
+        }
+        else
+        {
+	  // set espfs magic (set it valid)
+          uint32_t magic = ESPFS_MAGIC;
+          spi_flash_write( (int)getUserPageSectionStart(), (uint32_t *)&magic, sizeof(uint32_t) );
+	}
+        WEB_Init(); // reload the content
+      }
+      break;
+  }
+  return 0;
+}
+
+MultipartCtx * webServerContext = NULL; // multipart upload context for web server
+
+// this callback is called when user uploads the web-page
+int ICACHE_FLASH_ATTR cgiWebServerSetupUpload(HttpdConnData *connData)
+{
+  if( webServerContext == NULL )
+    webServerContext = multipartCreateContext( webServerSetupMultipartCallback );
+  
+  return multipartProcess(webServerContext, connData);
+}
diff --git a/esp-link/cgiwebserversetup.h b/esp-link/cgiwebserversetup.h
new file mode 100644
index 0000000..ffecb82
--- /dev/null
+++ b/esp-link/cgiwebserversetup.h
@@ -0,0 +1,8 @@
+#ifndef CGIWEBSERVER_H
+#define CGIWEBSERVER_H
+
+#include <httpd.h>
+
+int ICACHE_FLASH_ATTR cgiWebServerSetupUpload(HttpdConnData *connData);
+
+#endif /* CGIWEBSERVER_H */
diff --git a/esp-link/config.c b/esp-link/config.c
index 1af160a..10adc55 100644
--- a/esp-link/config.c
+++ b/esp-link/config.c
@@ -195,3 +195,43 @@ getFlashSize() {
     return 0;
   return 1 << size_id;
 }
+
+const uint32_t getUserPageSectionStart()
+{
+  enum flash_size_map map = system_get_flash_size_map();
+  switch(map)
+  {
+    case FLASH_SIZE_4M_MAP_256_256:
+      return FLASH_SECT + FIRMWARE_SIZE - 3*FLASH_SECT;// bootloader + firmware - 12KB (highly risky...)
+    case FLASH_SIZE_8M_MAP_512_512:
+      return FLASH_SECT + FIRMWARE_SIZE;
+    case FLASH_SIZE_16M_MAP_512_512:
+    case FLASH_SIZE_16M_MAP_1024_1024:
+    case FLASH_SIZE_32M_MAP_512_512:
+    case FLASH_SIZE_32M_MAP_1024_1024:
+      return 0x100000;
+    default:
+      return 0xFFFFFFFF;
+  }
+}
+
+const uint32_t getUserPageSectionEnd()
+{
+  enum flash_size_map map = system_get_flash_size_map();
+  switch(map)
+  {
+    case FLASH_SIZE_4M_MAP_256_256:
+      return FLASH_SECT + FIRMWARE_SIZE - 2*FLASH_SECT;
+    case FLASH_SIZE_8M_MAP_512_512:
+      return FLASH_SECT + FIRMWARE_SIZE + 2*FLASH_SECT;
+    case FLASH_SIZE_16M_MAP_512_512:
+    case FLASH_SIZE_16M_MAP_1024_1024:
+      return 0x1FC000;
+    case FLASH_SIZE_32M_MAP_512_512:
+    case FLASH_SIZE_32M_MAP_1024_1024:
+      return 0x3FC000;
+    default:
+      return 0xFFFFFFFF;
+  }
+}
+
diff --git a/esp-link/config.h b/esp-link/config.h
index 341d7e1..bf08df4 100644
--- a/esp-link/config.h
+++ b/esp-link/config.h
@@ -46,4 +46,7 @@ bool configRestore(void);
 void configWipe(void);
 const size_t getFlashSize();
 
+const uint32_t getUserPageSectionStart();
+const uint32_t getUserPageSectionEnd();
+
 #endif
diff --git a/esp-link/main.c b/esp-link/main.c
index 49a228a..596cfbd 100644
--- a/esp-link/main.c
+++ b/esp-link/main.c
@@ -19,6 +19,7 @@
 #include "cgimqtt.h"
 #include "cgiflash.h"
 #include "cgioptiboot.h"
+#include "cgiwebserversetup.h"
 #include "auth.h"
 #include "espfs.h"
 #include "uart.h"
@@ -30,6 +31,7 @@
 #include "log.h"
 #include "gpio.h"
 #include "cgiservices.h"
+#include "web-server.h"
 
 #ifdef SYSLOG
 #include "syslog.h"
@@ -96,6 +98,8 @@ HttpdBuiltInUrl builtInUrls[] = {
 #ifdef MQTT
   { "/mqtt", cgiMqtt, NULL },
 #endif
+  { "/web-server/upload", cgiWebServerSetupUpload, NULL },
+  { "*.json", WEB_CgiJsonHook, NULL }, //Catch-all cgi JSON queries
   { "*", cgiEspFsHook, NULL }, //Catch-all cgi function for the filesystem
   { NULL, NULL, NULL }
 };
@@ -147,11 +151,14 @@ void user_init(void) {
   // Wifi
   wifiInit();
   // init the flash filesystem with the html stuff
-  espFsInit(&_binary_espfs_img_start);
+  espFsInit(espLinkCtx, &_binary_espfs_img_start, ESPFS_MEMORY);
+  
   //EspFsInitResult res = espFsInit(&_binary_espfs_img_start);
   //os_printf("espFsInit %s\n", res?"ERR":"ok");
   // mount the http handlers
   httpdInit(builtInUrls, 80);
+  WEB_Init();
+  
   // init the wifi-serial transparent bridge (port 23)
   serbridgeInit(23, 2323);
   uart_add_recv_cb(&serbridgeUartCb);
diff --git a/espfs/espfs.c b/espfs/espfs.c
index f9942f3..111bfd7 100644
--- a/espfs/espfs.c
+++ b/espfs/espfs.c
@@ -30,6 +30,7 @@ It's written for use with httpd, but doesn't need to be used as such.
 #define os_malloc malloc
 #define os_free free
 #define os_memcpy memcpy
+#define os_memset memset
 #define os_strncmp strncmp
 #define os_strcmp strcmp
 #define os_strcpy strcpy
@@ -40,9 +41,21 @@ It's written for use with httpd, but doesn't need to be used as such.
 #include "espfsformat.h"
 #include "espfs.h"
 
-static char* espFsData = NULL;
+EspFsContext espLinkCtxDef;
+EspFsContext userPageCtxDef;
+
+EspFsContext * espLinkCtx = &espLinkCtxDef;
+EspFsContext * userPageCtx = &userPageCtxDef;
+
+struct EspFsContext
+{
+	char*       data;
+	EspFsSource source;
+	uint8_t     valid;
+};
 
 struct EspFsFile {
+	EspFsContext *ctx;
 	EspFsHeader *header;
 	char decompressor;
 	int32_t posDecomp;
@@ -67,29 +80,12 @@ Accessing the flash through the mem emulation at 0x40200000 is a bit hairy: All
 a memory exception, crashing the program.
 */
 
-EspFsInitResult ICACHE_FLASH_ATTR espFsInit(void *flashAddress) {
-	// base address must be aligned to 4 bytes
-	if (((int)flashAddress & 3) != 0) {
-		return ESPFS_INIT_RESULT_BAD_ALIGN;
-	}
-
-	// check if there is valid header at address
-	EspFsHeader testHeader;
-	os_memcpy(&testHeader, flashAddress, sizeof(EspFsHeader));
-	if (testHeader.magic != ESPFS_MAGIC) {
-		return ESPFS_INIT_RESULT_NO_IMAGE;
-	}
-
-	espFsData = (char *)flashAddress;
-	return ESPFS_INIT_RESULT_OK;
-}
-
 //Copies len bytes over from dst to src, but does it using *only*
 //aligned 32-bit reads. Yes, it's no too optimized but it's short and sweet and it works.
 
 //ToDo: perhaps os_memcpy also does unaligned accesses?
 #ifdef __ets__
-void ICACHE_FLASH_ATTR memcpyAligned(char *dst, char *src, int len) {
+void ICACHE_FLASH_ATTR memcpyAligned(char *dst, const char *src, int len) {
 	int x;
 	int w, b;
 	for (x=0; x<len; x++) {
@@ -106,6 +102,51 @@ void ICACHE_FLASH_ATTR memcpyAligned(char *dst, char *src, int len) {
 #define memcpyAligned memcpy
 #endif
 
+void ICACHE_FLASH_ATTR memcpyFromFlash(char *dst, const char *src, int len)
+{
+	if( spi_flash_read( (int)src, (void *)dst, len ) != SPI_FLASH_RESULT_OK )
+		os_memset( dst, 0, len ); // if read was not successful, reply with zeroes
+}
+
+// memcpy on MEMORY/FLASH file systems
+void espfs_memcpy( EspFsContext * ctx, void * dest, const void * src, int count )
+{
+	if( ctx->source == ESPFS_MEMORY )
+		os_memcpy( dest, src, count );
+	else
+		memcpyFromFlash(dest, src, count);
+}
+
+// aligned memcpy on MEMORY/FLASH file systems
+void espfs_memcpyAligned( EspFsContext * ctx, void * dest, const void * src, int count )
+{
+	if( ctx->source == ESPFS_MEMORY )
+		memcpyAligned(dest, src, count);
+	else
+		memcpyFromFlash(dest, src, count);
+}
+
+// initializes an EspFs context
+EspFsInitResult ICACHE_FLASH_ATTR espFsInit(EspFsContext *ctx, void *flashAddress, EspFsSource source) {
+	ctx->valid = 0;
+	ctx->source = source;
+	// base address must be aligned to 4 bytes
+	if (((int)flashAddress & 3) != 0) {
+		return ESPFS_INIT_RESULT_BAD_ALIGN;
+	}
+
+	// check if there is valid header at address
+	EspFsHeader testHeader;
+	espfs_memcpy(ctx, &testHeader, flashAddress, sizeof(EspFsHeader));
+	if (testHeader.magic != ESPFS_MAGIC) {
+		return ESPFS_INIT_RESULT_NO_IMAGE;
+	}
+
+	ctx->data = (char *)flashAddress;
+	ctx->valid = 1;
+	return ESPFS_INIT_RESULT_OK;
+}
+
 // Returns flags of opened file.
 int ICACHE_FLASH_ATTR espFsFlags(EspFsFile *fh) {
 	if (fh == NULL) {
@@ -116,57 +157,93 @@ int ICACHE_FLASH_ATTR espFsFlags(EspFsFile *fh) {
 	}
 
 	int8_t flags;
-	memcpyAligned((char*)&flags, (char*)&fh->header->flags, 1);
+	espfs_memcpyAligned(fh->ctx, (char*)&flags, (char*)&fh->header->flags, 1);
 	return (int)flags;
 }
 
+// creates and initializes an iterator over the espfs file system
+void ICACHE_FLASH_ATTR espFsIteratorInit(EspFsContext *ctx, EspFsIterator *iterator)
+{
+	if( ctx->data == NULL )
+	{
+		iterator->ctx = NULL;
+		return;
+	}
+	iterator->ctx = ctx;
+	iterator->position = NULL;
+}
+
+// moves iterator to the next file on espfs
+// returns 1 if iterator move was successful, otherwise 0 (last file)
+// iterator->header and iterator->name will contain file information
+int ICACHE_FLASH_ATTR espFsIteratorNext(EspFsIterator *iterator)
+{
+	if( iterator->ctx == NULL )
+		return 0;
+	
+	char * position = iterator->position;
+	if( position == NULL )
+		position = iterator->ctx->data; // first node
+	else
+	{
+		// jump the iterator to the next file
+		
+		position+=sizeof(EspFsHeader) + iterator->header.nameLen+iterator->header.fileLenComp;
+		if ((int)position&3) position+=4-((int)position&3); //align to next 32bit val
+	}
+	
+	iterator->position = position;
+	EspFsHeader * hdr = &iterator->header;
+	espfs_memcpy(iterator->ctx, hdr, position, sizeof(EspFsHeader));
+	
+	if (hdr->magic!=ESPFS_MAGIC) {
+#ifdef ESPFS_DBG
+		os_printf("Magic mismatch. EspFS image broken.\n");
+#endif
+		return 0;
+	}
+	if (hdr->flags&FLAG_LASTFILE) {
+		//os_printf("End of image.\n");
+		iterator->ctx = NULL; // invalidate the iterator
+		return 0;
+	}
+	
+	position += sizeof(EspFsHeader);
+	
+	//Grab the name of the file.
+	espfs_memcpy(iterator->ctx, iterator->name, position, sizeof(iterator->name));
+	
+	return 1;
+}
+
 //Open a file and return a pointer to the file desc struct.
-EspFsFile ICACHE_FLASH_ATTR *espFsOpen(char *fileName) {
-	if (espFsData == NULL) {
+EspFsFile ICACHE_FLASH_ATTR *espFsOpen(EspFsContext *ctx, char *fileName) {
+	EspFsIterator it;
+	espFsIteratorInit(ctx, &it);
+	if (it.ctx == NULL) {
 #ifdef ESPFS_DBG
 		os_printf("Call espFsInit first!\n");
 #endif
 		return NULL;
 	}
-	char *p=espFsData;
-	char *hpos;
-	char namebuf[256];
-	EspFsHeader h;
-	EspFsFile *r;
 	//Strip initial slashes
 	while(fileName[0]=='/') fileName++;
-	//Go find that file!
-	while(1) {
-		hpos=p;
-		//Grab the next file header.
-		os_memcpy(&h, p, sizeof(EspFsHeader));
-		if (h.magic!=ESPFS_MAGIC) {
-#ifdef ESPFS_DBG
-			os_printf("Magic mismatch. EspFS image broken.\n");
-#endif
-			return NULL;
-		}
-		if (h.flags&FLAG_LASTFILE) {
-			//os_printf("End of image.\n");
-			return NULL;
-		}
-		//Grab the name of the file.
-		p+=sizeof(EspFsHeader);
-		os_memcpy(namebuf, p, sizeof(namebuf));
-//		os_printf("Found file '%s'. Namelen=%x fileLenComp=%x, compr=%d flags=%d\n",
-//				namebuf, (unsigned int)h.nameLen, (unsigned int)h.fileLenComp, h.compression, h.flags);
-		if (os_strcmp(namebuf, fileName)==0) {
+	
+	//Search the file
+	while( espFsIteratorNext(&it) ) 
+	{
+		if (os_strcmp(it.name, fileName)==0) {
 			//Yay, this is the file we need!
-			p+=h.nameLen; //Skip to content.
-			r=(EspFsFile *)os_malloc(sizeof(EspFsFile)); //Alloc file desc mem
+			EspFsFile * r=(EspFsFile *)os_malloc(sizeof(EspFsFile)); //Alloc file desc mem
 			//os_printf("Alloc %p[%d]\n", r, sizeof(EspFsFile));
 			if (r==NULL) return NULL;
-			r->header=(EspFsHeader *)hpos;
-			r->decompressor=h.compression;
-			r->posComp=p;
-			r->posStart=p;
+			r->ctx = ctx;
+			r->header=(EspFsHeader *)it.position;
+			r->decompressor=it.header.compression;
+			r->posComp=it.position + it.header.nameLen  + sizeof(EspFsHeader);
+			r->posStart=it.position + it.header.nameLen  + sizeof(EspFsHeader);
 			r->posDecomp=0;
-			if (h.compression==COMPRESS_NONE) {
+			if (it.header.compression==COMPRESS_NONE) {
 				r->decompData=NULL;
 			} else {
 #ifdef ESPFS_DBG
@@ -176,10 +253,8 @@ EspFsFile ICACHE_FLASH_ATTR *espFsOpen(char *fileName) {
 			}
 			return r;
 		}
-		//We don't need this file. Skip name and file
-		p+=h.nameLen+h.fileLenComp;
-		if ((int)p&3) p+=4-((int)p&3); //align to next 32bit val
 	}
+	return NULL;
 }
 
 //Read len bytes from the given file into buff. Returns the actual amount of bytes read.
@@ -187,15 +262,15 @@ int ICACHE_FLASH_ATTR espFsRead(EspFsFile *fh, char *buff, int len) {
 	int flen, fdlen;
 	if (fh==NULL) return 0;
 	//Cache file length.
-	memcpyAligned((char*)&flen, (char*)&fh->header->fileLenComp, 4);
-	memcpyAligned((char*)&fdlen, (char*)&fh->header->fileLenDecomp, 4);
+	espfs_memcpyAligned(fh->ctx, (char*)&flen, (char*)&fh->header->fileLenComp, 4);
+	espfs_memcpyAligned(fh->ctx, (char*)&fdlen, (char*)&fh->header->fileLenDecomp, 4);
 	//Do stuff depending on the way the file is compressed.
 	if (fh->decompressor==COMPRESS_NONE) {
 		int toRead;
 		toRead=flen-(fh->posComp-fh->posStart);
 		if (len>toRead) len=toRead;
 //		os_printf("Reading %d bytes from %x\n", len, (unsigned int)fh->posComp);
-		memcpyAligned(buff, fh->posComp, len);
+		espfs_memcpyAligned(fh->ctx, buff, fh->posComp, len);
 		fh->posDecomp+=len;
 		fh->posComp+=len;
 //		os_printf("Done reading %d bytes, pos=%x\n", len, fh->posComp);
@@ -211,5 +286,8 @@ void ICACHE_FLASH_ATTR espFsClose(EspFsFile *fh) {
 	os_free(fh);
 }
 
-
+// checks if the file system is valid (detect if the content is an espfs image or random data)
+int ICACHE_FLASH_ATTR espFsIsValid(EspFsContext *ctx) {
+	return ctx->valid;
+}
 
diff --git a/espfs/espfs.h b/espfs/espfs.h
index c8e13e7..654bc27 100644
--- a/espfs/espfs.h
+++ b/espfs/espfs.h
@@ -1,19 +1,42 @@
 #ifndef ESPFS_H
 #define ESPFS_H
 
+#include "espfsformat.h"
+
 typedef enum {
 	ESPFS_INIT_RESULT_OK,
 	ESPFS_INIT_RESULT_NO_IMAGE,
 	ESPFS_INIT_RESULT_BAD_ALIGN,
 } EspFsInitResult;
 
+// Only 1 MByte of the flash can be directly accessed with ESP8266
+// If flash size is >1 Mbyte, SDK API is required to retrieve flash content
+typedef enum {
+	ESPFS_MEMORY, // read data directly from memory (fast, max 1 MByte)
+	ESPFS_FLASH,  // read data from flash using SDK API (no limit for the size)
+} EspFsSource;
+
 typedef struct EspFsFile EspFsFile;
+typedef struct EspFsContext EspFsContext;
+
+typedef struct {
+	EspFsHeader   header;      // the header of the current file
+	EspFsContext *ctx;         // pointer to espfs context
+	char          name[256];   // the name of the current file
+	char         *position;    // position of the iterator (pointer on the file system)
+} EspFsIterator;
+
+extern EspFsContext * espLinkCtx;
+extern EspFsContext * userPageCtx;
 
-EspFsInitResult espFsInit(void *flashAddress);
-EspFsFile *espFsOpen(char *fileName);
+EspFsInitResult espFsInit(EspFsContext *ctx, void *flashAddress, EspFsSource source);
+EspFsFile *espFsOpen(EspFsContext *ctx, char *fileName);
+int espFsIsValid(EspFsContext *ctx);
 int espFsFlags(EspFsFile *fh);
 int espFsRead(EspFsFile *fh, char *buff, int len);
 void espFsClose(EspFsFile *fh);
 
+void espFsIteratorInit(EspFsContext *ctx, EspFsIterator *iterator);
+int espFsIteratorNext(EspFsIterator *iterator);
 
 #endif
\ No newline at end of file
diff --git a/html/home.html b/html/home.html
index 138222e..de9862f 100644
--- a/html/home.html
+++ b/html/home.html
@@ -123,6 +123,12 @@
                 <div class="popup pop-left">Size configured into bootloader, must match chip size</div>
               </div>
             </td></tr>
+            <tr><td>Webpage size</td><td>
+              <div>
+                <span class="system-upload-size"></span>
+                <div class="popup pop-left">The maximal size of the custom web page a user can upload.</div>
+              </div>
+            </td></tr>
             <tr><td>Current partition</td><td class="system-partition"></td></tr>
             <tr><td colspan=2 class="popup-target">Description:<br>
                 <div class="click-to-edit system-description">
diff --git a/html/userpage.js b/html/userpage.js
new file mode 100644
index 0000000..e9e7555
--- /dev/null
+++ b/html/userpage.js
@@ -0,0 +1,242 @@
+//===== Java script for user pages
+
+var loadCounter = 0;
+var refreshRate = 0;
+var refreshTimer;
+var hiddenInputs = [];
+
+function notifyResponse( data )
+{
+  Object.keys(data).forEach(function(v) {
+    var elems = document.getElementsByName(v);
+    var ndx;
+    for(ndx = 0; ndx < elems.length; ndx++ )
+    {
+      var el = elems[ndx];
+      if(el.tagName == "INPUT")
+      {
+        if( el.type == "radio" )
+        {
+          el.checked = data[v] == el.value;
+        }
+        else if( el.type == "checkbox" )
+        {
+          if( data[v] == "on" )
+            el.checked = true;
+          else if( data[v] == "off" )
+            el.checked = false;
+          else if( data[v] == true )
+            el.checked = true;
+          else
+            el.checked = false;
+        }
+        else
+        {
+          el.value = data[v];
+        }
+      }
+      if(el.tagName == "SELECT")
+      {
+        el.value = data[v];
+      }
+    }
+    var elem = document.getElementById(v);
+    if( elem != null )
+    {
+      if(elem.tagName == "P" || elem.tagName == "DIV" || elem.tagName == "SPAN" || elem.tagName == "TR" || elem.tagName == "TH" || elem.tagName == "TD" ||
+         elem.tagName == "TEXTAREA" )
+      {
+        elem.innerHTML = data[v];
+      }
+      if(elem.tagName == "UL" || elem.tagName == "OL")
+      {
+        var list = data[v];
+        var html = "";
+
+        for (var i=0; i<list.length; i++) {
+          html = html.concat("<li>" + list[i] + "</li>");
+        }
+
+        elem.innerHTML = html;
+      }
+      if(elem.tagName == "TABLE")
+      {
+        var list = data[v];
+        var html = "";
+
+        if( list.length > 0 )
+        {
+          var ths = list[0];
+          html = html.concat("<tr>");
+
+          for (var i=0; i<ths.length; i++) {
+            html = html.concat("<th>" + ths[i] + "</th>");
+          }
+
+          html = html.concat("</tr>");
+        }
+
+        for (var i=1; i<list.length; i++) {
+          var tds = list[i];
+          html = html.concat("<tr>");
+
+          for (var j=0; j<tds.length; j++) {
+            html = html.concat("<td>" + tds[j] + "</td>");
+          }
+          
+          html = html.concat("</tr>");
+        }
+        
+        elem.innerHTML = html;
+      }
+    }
+  });
+  
+  if( refreshRate != 0 )
+  {
+    clearTimeout(refreshTimer);
+    refreshTimer = setTimeout( function () {
+      ajaxJson("GET", window.location.pathname + ".json?reason=refresh", notifyResponse );
+    }, refreshRate );
+  }
+}
+
+function notifyButtonPressed( btnId )
+{
+  ajaxJson("POST", window.location.pathname + ".json?reason=button\&id=" + btnId, notifyResponse);
+}
+
+function refreshFormData()
+{
+  setTimeout( function () {
+    ajaxJson("GET", window.location.pathname + ".json?reason=refresh", function (resp) {
+      notifyResponse(resp);
+      if( loadCounter > 0 )
+      {
+        loadCounter--;
+        refreshFormData();
+      }
+    } );
+  } , 250);
+}
+
+function recalculateHiddenInputs()
+{
+  for(var i=0; i < hiddenInputs.length; i++)
+  {
+    var hinput = hiddenInputs[i];
+    var name = hinput.name;
+    
+    var elems = document.getElementsByName(name);
+    for(var j=0; j < elems.length; j++ )
+    {
+      var chk = elems[j];
+      var inptp = chk.type;
+      if( inptp == "checkbox" ) {
+        if( chk.checked )
+        {
+          hinput.disabled = true;
+          hinput.value = "on";
+        }
+        else
+        {
+          hinput.disabled = false;
+          hinput.value = "off";
+        }
+      }
+    }
+  }
+}
+
+document.addEventListener("DOMContentLoaded", function(){
+  // collect buttons
+  var btns = document.getElementsByTagName("button");
+  var ndx;
+
+  for (ndx = 0; ndx < btns.length; ndx++) {
+    var btn = btns[ndx];
+    var id = btn.getAttribute("id");
+    var onclk = btn.getAttribute("onclick");
+    var type = btn.getAttribute("type");
+    
+    if( id != null && onclk == null && type == "button" )
+    {
+      var fn;
+      eval( "fn = function() { notifyButtonPressed(\"" + id + "\") }" );
+      btn.onclick = fn;
+    }
+  }
+
+  // collect forms
+  var frms = document.getElementsByTagName("form");
+
+  for (ndx = 0; ndx < frms.length; ndx++) {
+    var frm = frms[ndx];
+    
+    var method = frm.method;
+    var action = frm.action;
+    
+    frm.method = "POST";
+    frm.action = window.location.pathname + ".json?reason=submit";
+    loadCounter = 4;
+
+    frm.onsubmit = function () {
+      recalculateHiddenInputs();
+      refreshFormData();
+      return true;
+    };
+  }
+
+  // collect metas
+  var metas = document.getElementsByTagName("meta");
+
+  for (ndx = 0; ndx < metas.length; ndx++) {
+    var meta = metas[ndx];
+    if( meta.getAttribute("name") == "refresh-rate" )
+    {
+      refreshRate = meta.getAttribute("content");
+    }
+  }
+
+  // collect checkboxes
+  var inputs = document.getElementsByTagName("input");
+
+  for (ndx = 0; ndx < inputs.length; ndx++) {
+    var inp = inputs[ndx];
+    if( inp.getAttribute("type") == "checkbox" )
+    {
+      var name = inp.getAttribute("name");
+      var hasHidden = false;
+      if( name != null )
+      {
+        var inpelems = document.getElementsByName(name);
+        for(var i=0; i < inpelems.length; i++ )
+        {
+           var inptp = inpelems[i].type;
+           if( inptp == "hidden" )
+             hasHidden = true;
+        }
+      }
+      
+      if( !hasHidden )
+      {
+        var parent = inp.parentElement;
+ 
+        var input = document.createElement("input");
+        input.type = "hidden";
+        input.name = inp.name;
+
+	parent.appendChild(input);
+        hiddenInputs.push(input);
+      }
+    }
+  }
+
+  // load variables at first time
+  var loadVariables = function() {
+    ajaxJson("GET", window.location.pathname + ".json?reason=load", notifyResponse,
+      function () { setTimeout(loadVariables, 1000); }
+    );
+  };
+  loadVariables();
+});
diff --git a/html/web-server.html b/html/web-server.html
new file mode 100644
index 0000000..a5a1d41
--- /dev/null
+++ b/html/web-server.html
@@ -0,0 +1,29 @@
+  <div id="main">
+    <div class="header">
+      <h1>Web Server</h1>
+    </div>
+
+    <div class="content">
+      <p>User defined web pages can be uploaded to esp-link. This is useful if esp-link acts as a web server while MCU provides
+        the measurement data.</p>
+
+      <form method="post" action="web-server/upload" name="submit" enctype="multipart/form-data" onSubmit="return onSubmit()">
+        The custom web page to upload: <input type="file" name="webpage">
+        <input type="submit" name="submit" value="Submit">
+      </form>
+      
+    </div>
+    
+  </div>
+  
+  <script>
+   var allowSubmit = true;
+
+   function onSubmit() {
+      setTimeout(function() {
+                    window.location.reload();
+                 }, 1000);
+      return true;
+   }
+</script>
+</body></html>
diff --git a/httpd/httpd.c b/httpd/httpd.c
index f3c5594..bc16649 100644
--- a/httpd/httpd.c
+++ b/httpd/httpd.c
@@ -132,6 +132,7 @@ static void ICACHE_FLASH_ATTR httpdRetireConn(HttpdConnData *conn) {
   if (conn->post->buff != NULL) os_free(conn->post->buff);
   conn->cgi = NULL;
   conn->post->buff = NULL;
+  conn->post->multipartBoundary = NULL;
 }
 
 //Stupid li'l helper function that returns the value of a hex char.
@@ -354,14 +355,18 @@ static void ICACHE_FLASH_ATTR httpdProcessRequest(HttpdConnData *conn) {
     if (conn->cgi == NULL) {
       while (builtInUrls[i].url != NULL) {
         int match = 0;
+        int urlLen = os_strlen(builtInUrls[i].url);
         //See if there's a literal match
         if (os_strcmp(builtInUrls[i].url, conn->url) == 0) match = 1;
         //See if there's a wildcard match
-        if (builtInUrls[i].url[os_strlen(builtInUrls[i].url) - 1] == '*' &&
-          os_strncmp(builtInUrls[i].url, conn->url, os_strlen(builtInUrls[i].url) - 1) == 0) match = 1;
+        if (builtInUrls[i].url[urlLen - 1] == '*' &&
+          os_strncmp(builtInUrls[i].url, conn->url, urlLen - 1) == 0) match = 1;
+        else if (builtInUrls[i].url[0] == '*' && ( strlen(conn->url) >= urlLen -1 )  &&
+          os_strncmp(builtInUrls[i].url + 1, conn->url + strlen(conn->url) - urlLen + 1, urlLen - 1) == 0) match = 1;
         if (match) {
           //os_printf("Is url index %d\n", i);
           conn->cgiData = NULL;
+	  conn->cgiResponse = NULL;
           conn->cgi = builtInUrls[i].cgiCb;
           conn->cgiArg = builtInUrls[i].cgiArg;
           break;
@@ -509,6 +514,7 @@ static void ICACHE_FLASH_ATTR httpdRecvCb(void *arg, char *data, unsigned short
       if (data[x] == '\n' && (char *)os_strstr(conn->priv->head, "\r\n\r\n") != NULL) {
         //Indicate we're done with the headers.
         conn->post->len = 0;
+	conn->post->multipartBoundary = NULL;
         //Reset url data
         conn->url = NULL;
         //Iterate over all received headers and parse them.
@@ -621,3 +627,43 @@ void ICACHE_FLASH_ATTR httpdInit(HttpdBuiltInUrl *fixedUrls, int port) {
   espconn_accept(&httpdConn);
   espconn_tcp_set_max_con_allow(&httpdConn, MAX_CONN);
 }
+
+// looks up connection handle based on ip / port
+HttpdConnData * ICACHE_FLASH_ATTR  httpdLookUpConn(uint8_t * ip, int port) {
+  int i;
+
+  for (i = 0; i<MAX_CONN; i++)
+  {
+    HttpdConnData *conn = connData+i;
+    
+    if (conn->conn == NULL)
+      continue;
+    if (conn->cgi == NULL)
+      continue;
+    if (conn->conn->proto.tcp->remote_port != port )
+      continue;
+    if (os_memcmp(conn->conn->proto.tcp->remote_ip, ip, 4) != 0)
+      continue;
+    
+    return conn;
+  }
+  return NULL;
+}
+
+// this method is used for setting the response of a CGI handler outside of the HTTP callback
+// this method useful at the following scenario:
+//   Browser -> CGI handler -> MCU request
+//   MCU response -> CGI handler -> browser
+// when MCU response arrives, the handler looks up connection based on ip/port and call httpdSetCGIResponse with the data to transmit
+
+int ICACHE_FLASH_ATTR httpdSetCGIResponse(HttpdConnData * conn, void * response) {
+  char sendBuff[MAX_SENDBUFF_LEN];
+  conn->priv->sendBuff = sendBuff;
+  conn->priv->sendBuffLen = 0;
+
+  conn->cgiResponse = response;
+  httpdProcessRequest(conn);
+  conn->cgiResponse = NULL;
+    
+  return HTTPD_CGI_DONE;
+}
diff --git a/httpd/httpd.h b/httpd/httpd.h
index 33a0700..32d9394 100644
--- a/httpd/httpd.h
+++ b/httpd/httpd.h
@@ -30,6 +30,7 @@ struct HttpdConnData {
 	const void *cgiArg;
 	void *cgiData;
 	void *cgiPrivData; // Used for streaming handlers storing state between requests
+	void *cgiResponse; // used for forwarding response to the CGI handler
 	HttpdPriv *priv;
 	cgiSendCallback cgi;
 	HttpdPostData *post;
@@ -66,5 +67,7 @@ void ICACHE_FLASH_ATTR httpdEndHeaders(HttpdConnData *conn);
 int ICACHE_FLASH_ATTR httpdGetHeader(HttpdConnData *conn, char *header, char *ret, int retLen);
 int ICACHE_FLASH_ATTR httpdSend(HttpdConnData *conn, const char *data, int len);
 void ICACHE_FLASH_ATTR httpdFlush(HttpdConnData *conn);
+HttpdConnData * ICACHE_FLASH_ATTR  httpdLookUpConn(uint8_t * ip, int port);
+int ICACHE_FLASH_ATTR  httpdSetCGIResponse(HttpdConnData * conn, void *response);
 
 #endif
diff --git a/httpd/httpdespfs.c b/httpd/httpdespfs.c
index c6f2c0c..e080bdc 100644
--- a/httpd/httpdespfs.c
+++ b/httpd/httpdespfs.c
@@ -14,11 +14,12 @@ Connector to let httpd use the espfs filesystem to serve the files in it.
  */
 #include "httpdespfs.h"
 
+#define MAX_URL_LEN 255
+
 // The static files marked with FLAG_GZIP are compressed and will be served with GZIP compression.
 // If the client does not advertise that he accepts GZIP send following warning message (telnet users for e.g.)
 static const char *gzipNonSupportedMessage = "HTTP/1.0 501 Not implemented\r\nServer: esp8266-httpd/"HTTPDVER"\r\nConnection: close\r\nContent-Type: text/plain\r\nContent-Length: 52\r\n\r\nYour browser does not accept gzip-compressed data.\r\n";
 
-
 //This is a catch-all cgi function. It takes the url passed to it, looks up the corresponding
 //path in the filesystem and if it exists, passes the file through. This simulates what a normal
 //webserver would do with static files.
@@ -40,9 +41,21 @@ cgiEspFsHook(HttpdConnData *connData) {
 
 	if (file==NULL) {
 		//First call to this cgi. Open the file so we can read it.
-		file=espFsOpen(connData->url);
+		file=espFsOpen(espLinkCtx, connData->url);
 		if (file==NULL) {
-			return HTTPD_CGI_NOTFOUND;
+			if( espFsIsValid(userPageCtx) )
+			{
+				int maxLen = strlen(connData->url) * 2 + 1;
+				if( maxLen > MAX_URL_LEN )
+					maxLen = MAX_URL_LEN;
+				char decodedURL[maxLen];
+				httpdUrlDecode(connData->url, strlen(connData->url), decodedURL, maxLen);
+				file = espFsOpen(userPageCtx, decodedURL );
+				if( file == NULL )
+					return HTTPD_CGI_NOTFOUND;
+			}
+			else
+				return HTTPD_CGI_NOTFOUND;
 		}
 
 		// The gzip checking code is intentionally without #ifdefs because checking
diff --git a/httpd/multipart.c b/httpd/multipart.c
new file mode 100644
index 0000000..d709798
--- /dev/null
+++ b/httpd/multipart.c
@@ -0,0 +1,301 @@
+#include <esp8266.h>
+#include <osapi.h>
+
+#include "multipart.h"
+#include "cgi.h"
+
+#define BOUNDARY_SIZE 100
+
+typedef enum {
+  STATE_SEARCH_BOUNDARY = 0, // state: searching multipart boundary
+  STATE_SEARCH_HEADER,       // state: search multipart file header
+  STATE_SEARCH_HEADER_END,   // state: search the end of the file header
+  STATE_UPLOAD_FILE,         // state: read file content
+  STATE_ERROR,               // state: error (stop processing)
+} MultipartState;
+
+struct _MultipartCtx {
+  MultipartCallback callBack;           // callback for multipart events
+  int               position;           // current file position
+  int               startTime;          // timestamp when connection was initiated
+  int               recvPosition;       // receive position (how many bytes was processed from the HTTP post)
+  char *            boundaryBuffer;     // buffer used for boundary detection
+  int               boundaryBufferPtr;  // pointer in the boundary buffer
+  MultipartState    state;              // multipart processing state
+};
+
+// this method is responsible for creating the multipart context
+MultipartCtx * ICACHE_FLASH_ATTR multipartCreateContext(MultipartCallback callback)
+{
+  MultipartCtx * ctx = (MultipartCtx *)os_malloc(sizeof(MultipartCtx));
+  ctx->callBack = callback;
+  ctx->position = ctx->startTime = ctx->recvPosition = ctx->boundaryBufferPtr = 0;
+  ctx->boundaryBuffer = NULL;
+  ctx->state = STATE_SEARCH_BOUNDARY;
+  return ctx;
+}
+
+// for allocating buffer for multipart upload 
+void ICACHE_FLASH_ATTR multipartAllocBoundaryBuffer(MultipartCtx * context)
+{
+  if( context->boundaryBuffer == NULL )
+    context->boundaryBuffer = (char *)os_malloc(3*BOUNDARY_SIZE + 1);
+  context->boundaryBufferPtr = 0;
+}
+
+// for freeing multipart buffer
+void ICACHE_FLASH_ATTR multipartFreeBoundaryBuffer(MultipartCtx * context)
+{
+  if( context->boundaryBuffer != NULL )
+  {
+    os_free(context->boundaryBuffer);
+    context->boundaryBuffer = NULL;
+  }
+}
+
+// for destroying the context
+void ICACHE_FLASH_ATTR multipartDestroyContext(MultipartCtx * context)
+{
+  multipartFreeBoundaryBuffer(context);
+  os_free(context);
+}
+
+// this is because of os_memmem is missing
+void * mp_memmem(const void *l, size_t l_len, const void *s, size_t s_len)
+{
+	register char *cur, *last;
+	const char *cl = (const char *)l;
+	const char *cs = (const char *)s;
+
+	/* we need something to compare */
+	if (l_len == 0 || s_len == 0)
+		return NULL;
+
+	/* "s" must be smaller or equal to "l" */
+	if (l_len < s_len)
+		return NULL;
+
+	/* special case where s_len == 1 */
+	if (s_len == 1)
+		return memchr(l, (int)*cs, l_len);
+
+	/* the last position where its possible to find "s" in "l" */
+	last = (char *)cl + l_len - s_len;
+
+	for (cur = (char *)cl; cur <= last; cur++)
+		if (cur[0] == cs[0] && memcmp(cur, cs, s_len) == 0)
+			return cur;
+
+	return NULL;
+}
+
+
+// this method is for processing data coming from the HTTP post request
+//   context:   the multipart context
+//   boundary:  a string which indicates boundary
+//   data:      the received data
+//   len:       the received data length (can't be bigger than BOUNDARY_SIZE)
+//   last:      last packet indicator
+//
+// Detecting a boundary is not easy. One has to take care of boundaries which are splitted in 2 packets
+//   [Packet 1, 5 bytes of the boundary][Packet 2, remaining 10 bytes of the boundary];
+//
+// Algorythm:
+//   - create a buffer which size is 3*BOUNDARY_SIZE
+//   - put data into the buffer as long as the buffer size is smaller than 2*BOUNDARY_SIZE
+//   - search boundary in the received buffer, if found: boundary reached -> process data before boundary -> process boundary
+//   - if not found -> process the first BOUNDARY_SIZE amount of bytes from the buffer
+//   - remove processed data from the buffer
+// this algorythm guarantees that no boundary loss will happen
+
+int ICACHE_FLASH_ATTR multipartProcessData(MultipartCtx * context, char * boundary, char * data, int len, int last)
+{
+  if( len != 0 ) // add data to the boundary buffer
+  {
+    os_memcpy(context->boundaryBuffer + context->boundaryBufferPtr, data, len);
+    
+    context->boundaryBufferPtr += len;
+    context->boundaryBuffer[context->boundaryBufferPtr] = 0;
+  }
+  
+  while( context->boundaryBufferPtr > 0 )
+  {
+    if( ! last && context->boundaryBufferPtr <= 2 * BOUNDARY_SIZE ) // return if buffer is too small and not the last packet is processed
+      return 0;
+  
+    int dataSize = BOUNDARY_SIZE;
+  
+    char * boundaryLoc = mp_memmem( context->boundaryBuffer, context->boundaryBufferPtr, boundary, os_strlen(boundary) );
+    if( boundaryLoc != NULL )
+    {
+      int pos = boundaryLoc - context->boundaryBuffer;
+      if( pos > BOUNDARY_SIZE ) // process in the next call
+        boundaryLoc = NULL;
+      else
+        dataSize = pos;
+    }
+    
+    if( dataSize != 0 ) // data to process
+    {
+      switch( context->state )
+      {
+        case STATE_SEARCH_HEADER:
+        case STATE_SEARCH_HEADER_END:
+          {
+            char * chr = os_strchr( context->boundaryBuffer, '\n' );
+            if( chr != NULL )
+            {
+	      // chop datasize to contain only one line
+              int pos = chr - context->boundaryBuffer + 1;
+              if( pos < dataSize ) // if chop smaller than the dataSize, delete the boundary
+              {
+                dataSize = pos;
+                boundaryLoc = NULL; // process boundary next time
+              }
+              if( context->state == STATE_SEARCH_HEADER_END )
+              {
+                if( pos == 1 || ( ( pos == 2 ) && ( context->boundaryBuffer[0] == '\r' ) ) ) // empty line?
+                {
+                  context->state = STATE_UPLOAD_FILE;
+                  context->position = 0;
+                }
+              }
+              else if( os_strncmp( context->boundaryBuffer, "Content-Disposition:",  20 ) == 0 )
+              {
+                char * fnam = os_strstr( context->boundaryBuffer, "filename=" );
+                if( fnam != NULL )
+                {
+                  int pos = fnam - context->boundaryBuffer + 9;
+                  if( pos < dataSize )
+                  {
+                    while(context->boundaryBuffer[pos] == ' ') pos++; // skip spaces
+                    if( context->boundaryBuffer[pos] == '"' ) // quote start
+                    {
+                      pos++;
+                      int start = pos;
+                      while( pos < context->boundaryBufferPtr )
+                      {
+                        if( context->boundaryBuffer[pos] == '"' ) // quote end
+                          break;
+                        pos++;
+                      }
+                      if( pos < context->boundaryBufferPtr )
+                      {
+                        context->boundaryBuffer[pos] = 0; // terminating zero for the file name
+                        os_printf("Uploading file: %s\n", context->boundaryBuffer + start);
+                        if( context->callBack( FILE_START, context->boundaryBuffer + start, pos - start, 0 ) ) // FILE_START callback
+			  return 1; // if an error happened
+                        context->boundaryBuffer[pos] = '"'; // restore the original quote
+                        context->state = STATE_SEARCH_HEADER_END;
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+          break;
+        case STATE_UPLOAD_FILE:
+          {
+            char c = context->boundaryBuffer[dataSize];
+            context->boundaryBuffer[dataSize] = 0; // add terminating zero (for easier handling)
+            if( context->callBack( FILE_DATA, context->boundaryBuffer, dataSize, context->position ) ) // FILE_DATA callback
+	      return 1;
+            context->boundaryBuffer[dataSize] = c;
+            context->position += dataSize;
+          }
+          break;
+        default:
+          break;
+      }
+    }
+    
+    if( boundaryLoc != NULL ) // boundary found?
+    {
+      dataSize += os_strlen(boundary); // jump over the boundary
+      if( context->state == STATE_UPLOAD_FILE )
+      {
+        if( context->callBack( FILE_DONE, NULL, 0, context->position ) ) // file done callback
+	  return 1; // if an error happened
+        os_printf("File upload done\n");
+      }
+
+      context->state = STATE_SEARCH_HEADER; // search the next header
+    }
+    
+    // move the buffer back with dataSize
+    context->boundaryBufferPtr -= dataSize;
+    os_memcpy(context->boundaryBuffer, context->boundaryBuffer + dataSize, context->boundaryBufferPtr);
+  }
+  return 0;
+}
+
+// for processing multipart requests
+int ICACHE_FLASH_ATTR multipartProcess(MultipartCtx * context, HttpdConnData * connData )
+{
+  if (connData->conn==NULL) return HTTPD_CGI_DONE; // Connection aborted. Clean up.
+  
+  if (connData->requestType == HTTPD_METHOD_POST) {
+    HttpdPostData *post = connData->post;
+    
+    if( post->multipartBoundary == NULL )
+    {
+      errorResponse(connData, 404, "Only multipart POST is supported");
+      return HTTPD_CGI_DONE;
+    }
+
+    if( connData->startTime != context->startTime )
+    {
+      // reinitialize, as this is a new request
+      context->position = 0;
+      context->recvPosition = 0;
+      context->startTime = connData->startTime;
+      context->state = STATE_SEARCH_BOUNDARY;
+ 
+      multipartAllocBoundaryBuffer(context);
+    }
+
+    if( context->state != STATE_ERROR )
+    {
+      int feed = 0;
+      while( feed < post->buffLen )
+      {
+        int len = post->buffLen - feed;
+        if( len > BOUNDARY_SIZE )
+          len = BOUNDARY_SIZE;
+        if( multipartProcessData(context, post->multipartBoundary, post->buff + feed, len, 0) )
+        {
+          context->state = STATE_ERROR;
+          break;
+        }
+        feed += len;
+      }
+    }
+    
+    context->recvPosition += post->buffLen;
+    if( context->recvPosition < post->len )
+      return HTTPD_CGI_MORE;
+
+    if( context->state != STATE_ERROR )
+    {
+      // this is the last package, process the remaining data
+      if( multipartProcessData(context, post->multipartBoundary, NULL, 0, 1) )
+        context->state = STATE_ERROR;
+    }
+    
+    multipartFreeBoundaryBuffer( context );
+    
+    if( context->state == STATE_ERROR )
+      errorResponse(connData, 400, "Invalid file upload!");
+    else
+    {
+      httpdStartResponse(connData, 204);
+      httpdEndHeaders(connData);
+    }
+    return HTTPD_CGI_DONE;
+  }
+  else {
+    errorResponse(connData, 404, "Only multipart POST is supported");
+    return HTTPD_CGI_DONE;
+  }
+}
diff --git a/httpd/multipart.h b/httpd/multipart.h
new file mode 100644
index 0000000..87a4bb2
--- /dev/null
+++ b/httpd/multipart.h
@@ -0,0 +1,32 @@
+#ifndef MULTIPART_H
+#define MULTIPART_H
+
+#include <httpd.h>
+
+typedef enum {
+  FILE_START,   // multipart: the start of a new file 
+  FILE_DATA,    // multipart: file data
+  FILE_DONE,    // multipart: file end
+} MultipartCmd;
+
+// multipart callback
+// -> FILE_START : data+dataLen contains the filename, position is 0
+// -> FILE_DATA  : data+dataLen contains file data, position is the file position
+// -> FILE_DONE  : data+dataLen is 0, position is the complete file size
+
+typedef int (* MultipartCallback)(MultipartCmd cmd, char *data, int dataLen, int position);
+
+struct _MultipartCtx; // the context for multipart listening
+
+typedef struct _MultipartCtx MultipartCtx;
+
+// use this for creating a multipart context
+MultipartCtx * ICACHE_FLASH_ATTR multipartCreateContext(MultipartCallback callback);
+
+// for destroying multipart context
+void ICACHE_FLASH_ATTR multipartDestroyContext(MultipartCtx * context);
+
+// use this function for processing HTML multipart updates
+int ICACHE_FLASH_ATTR multipartProcess(MultipartCtx * context, HttpdConnData * post );
+
+#endif /* MULTIPART_H */
diff --git a/serial/serbridge.c b/serial/serbridge.c
index 66b180c..9f782bb 100644
--- a/serial/serbridge.c
+++ b/serial/serbridge.c
@@ -23,7 +23,7 @@ static struct espconn serbridgeConn2; // programming port
 static esp_tcp serbridgeTcp1, serbridgeTcp2;
 static int8_t mcu_reset_pin, mcu_isp_pin;
 
-extern uint8_t slip_disabled;   // disable slip to allow flashing of attached MCU
+uint8_t in_mcu_flashing;   // for disabling slip during MCU flashing
 
 void (*programmingCB)(char *buffer, short length) = NULL;
 
@@ -124,14 +124,14 @@ telnetUnwrap(uint8_t *inBuf, int len, uint8_t state)
 #ifdef SERBR_DBG
         else { os_printf("MCU isp: no pin\n"); }
 #endif
-        slip_disabled++;
+        in_mcu_flashing++;
         break;
       case RTS_OFF:
         if (mcu_isp_pin >= 0) {
           GPIO_OUTPUT_SET(mcu_isp_pin, 1);
           os_delay_us(100L);
         }
-        if (slip_disabled > 0) slip_disabled--;
+        if (in_mcu_flashing > 0) in_mcu_flashing--;
         break;
       }
       state = TN_end;
@@ -222,7 +222,7 @@ serbridgeRecvCb(void *arg, char *data, unsigned short len)
     //if (mcu_isp_pin >= 0) GPIO_OUTPUT_SET(mcu_isp_pin, 1);
     os_delay_us(1000L); // wait a millisecond before writing to the UART below
     conn->conn_mode = cmPGM;
-    slip_disabled++; // disable SLIP so it doesn't interfere with flashing
+    in_mcu_flashing++; // disable SLIP so it doesn't interfere with flashing
 #ifdef SKIP_AT_RESET
     serledFlash(50); // short blink on serial LED
     return;
@@ -355,7 +355,7 @@ serbridgeUartCb(char *buf, short length)
 {
   if (programmingCB) {
     programmingCB(buf, length);
-  } else if (!flashConfig.slip_enable || slip_disabled > 0) {
+  } else if (!flashConfig.slip_enable || in_mcu_flashing > 0) {
     //os_printf("SLIP: disabled got %d\n", length);
     console_process(buf, length);
   } else {
@@ -504,3 +504,8 @@ serbridgeInit(int port1, int port2)
   espconn_tcp_set_max_con_allow(&serbridgeConn2, MAX_CONN);
   espconn_regist_time(&serbridgeConn2, SER_BRIDGE_TIMEOUT, 0);
 }
+
+int  ICACHE_FLASH_ATTR serbridgeInMCUFlashing()
+{
+  return in_mcu_flashing;
+}
diff --git a/serial/serbridge.h b/serial/serbridge.h
index aad593e..ed661e1 100644
--- a/serial/serbridge.h
+++ b/serial/serbridge.h
@@ -36,6 +36,8 @@ void ICACHE_FLASH_ATTR serbridgeInitPins(void);
 void ICACHE_FLASH_ATTR serbridgeUartCb(char *buf, short len);
 void ICACHE_FLASH_ATTR serbridgeReset();
 
+int  ICACHE_FLASH_ATTR serbridgeInMCUFlashing();
+
 // callback when receiving UART chars when in programming mode
 extern void (*programmingCB)(char *buffer, short length);
 
diff --git a/serial/slip.c b/serial/slip.c
index 76d8f97..2f15186 100644
--- a/serial/slip.c
+++ b/serial/slip.c
@@ -13,8 +13,6 @@
 #define DBG(format, ...) do { } while(0)
 #endif
 
-uint8_t slip_disabled;   // temporarily disable slip to allow flashing of attached MCU
-
 extern void ICACHE_FLASH_ATTR console_process(char *buf, short len);
 
 // This SLIP parser tries to conform to RFC 1055 https://tools.ietf.org/html/rfc1055.
diff --git a/web-server/web-server.c b/web-server/web-server.c
new file mode 100644
index 0000000..0d323a2
--- /dev/null
+++ b/web-server/web-server.c
@@ -0,0 +1,454 @@
+#include "web-server.h"
+
+#include <espconn.h>
+
+#include "espfs.h"
+#include "config.h"
+#include "cgi.h"
+#include "cmd.h"
+#include "serbridge.h"
+
+// the file is responsible for handling user defined web-pages
+// - collects HTML files from user image, shows them on the left frame
+// - handles JSON data coming from the browser
+// - handles SLIP messages coming from MCU
+
+#define WEB_CB "webCb"
+#define MAX_ARGUMENT_BUFFER_SIZE 1024
+
+struct ArgumentBuffer
+{
+	char argBuffer[MAX_ARGUMENT_BUFFER_SIZE];
+	int  argBufferPtr;
+	int  numberOfArgs;
+};
+
+static char* web_server_reasons[] = {
+  "load",     // readable name for RequestReason::LOAD
+  "refresh",  // readable name for RequestReason::REFRESH
+  "button",   // readable name for RequestReason::BUTTON
+  "submit"    // readable name for RequestReason::SUBMIT
+};
+
+// this variable contains the names of the user defined pages
+// this information appears at the left frame below of the built in URL-s
+// format:    ,"UserPage1", "/UserPage1.html", "UserPage2", "/UserPage2.html", 
+char * webServerPages = NULL;
+
+char * ICACHE_FLASH_ATTR WEB_UserPages()
+{
+	return webServerPages;
+}
+
+// generates the content of webServerPages variable (called at booting/web page uploading)
+void ICACHE_FLASH_ATTR WEB_BrowseFiles()
+{
+	char buffer[1024];
+	buffer[0] = 0;
+	
+	if( espFsIsValid( userPageCtx ) )
+	{
+		EspFsIterator it;
+		espFsIteratorInit(userPageCtx, &it);
+		while( espFsIteratorNext(&it) )
+		{
+			int nameLen = os_strlen(it.name);
+			if( nameLen >= 6 )
+			{
+				// fetch HTML files
+				if( os_strcmp( it.name + nameLen-5, ".html" ) == 0 )
+				{
+					int slashPos = nameLen - 5;
+					
+					// chop path and .html from the name
+					while( slashPos > 0 && it.name[slashPos-1] != '/' )
+						slashPos--;
+					
+					// here we check buffer overrun
+					int maxLen = 10 + os_strlen( it.name ) + (nameLen - slashPos -5);
+					if( maxLen >= sizeof(buffer) )
+						break;
+					
+					os_strcat(buffer, ", \"");
+					
+					int writePos = os_strlen(buffer);
+					for( int i=slashPos; i < nameLen-5; i++ )
+					  buffer[writePos++] = it.name[i];
+					buffer[writePos] = 0; // terminating zero
+					
+					os_strcat(buffer, "\", \"/");
+					os_strcat(buffer, it.name);
+					os_strcat(buffer, "\"");
+				}
+			}
+		}
+	}
+	
+	if( webServerPages != NULL )
+		os_free( webServerPages );
+	
+	int len = os_strlen(buffer) + 1;
+	webServerPages = (char *)os_malloc( len );
+	os_memcpy( webServerPages, buffer, len );
+}
+
+// initializer
+void ICACHE_FLASH_ATTR WEB_Init()
+{
+	espFsInit(userPageCtx, (void *)getUserPageSectionStart(), ESPFS_FLASH);
+	if( espFsIsValid( userPageCtx ) )
+		os_printf("Valid user file system found!\n");
+	else
+		os_printf("No user file system found!\n");
+	WEB_BrowseFiles(); // collect user defined HTML files
+}
+
+// initializes the argument buffer
+static void WEB_argInit(struct ArgumentBuffer * argBuffer)
+{
+	argBuffer->numberOfArgs = 0;
+	argBuffer->argBufferPtr = 0;
+}
+
+// adds an argument to the argument buffer (returns 0 if successful)
+static int  WEB_addArg(struct ArgumentBuffer * argBuffer, char * arg, int argLen )
+{
+	if( argBuffer->argBufferPtr + argLen + sizeof(int) >= MAX_ARGUMENT_BUFFER_SIZE )
+		return -1; // buffer overflow
+	
+	os_memcpy(argBuffer->argBuffer + argBuffer->argBufferPtr, &argLen, sizeof(int));
+	
+	if( argLen != 0 )
+	{
+		os_memcpy( argBuffer->argBuffer + argBuffer->argBufferPtr + sizeof(int), arg, argLen );
+		argBuffer->numberOfArgs++;
+	}
+	
+	argBuffer->argBufferPtr += argLen + sizeof(int);
+	return 0;
+}
+
+// creates and sends a SLIP message from the argument buffer
+static void WEB_sendArgBuffer(struct ArgumentBuffer * argBuffer, HttpdConnData *connData, int id, RequestReason reason)
+{
+	cmdResponseStart(CMD_WEB_REQ_CB, id, 4 + argBuffer->numberOfArgs);
+	uint16_t r = (uint16_t)reason;
+	cmdResponseBody(&r, sizeof(uint16_t));                                      // 1st argument: reason
+	cmdResponseBody(&connData->conn->proto.tcp->remote_ip, 4);                  // 2nd argument: IP
+	cmdResponseBody(&connData->conn->proto.tcp->remote_port, sizeof(uint16_t)); // 3rd argument: port
+	cmdResponseBody(connData->url, os_strlen(connData->url));                   // 4th argument: URL
+	
+	int p = 0;
+	for( int j=0; j < argBuffer->numberOfArgs; j++ )
+	{
+		int argLen;
+		os_memcpy( &argLen, argBuffer->argBuffer + p, sizeof(int) );
+		
+		char * arg = argBuffer->argBuffer + p + sizeof(int);
+		cmdResponseBody(arg, argLen);
+		p += argLen + sizeof(int);
+	}
+	
+	cmdResponseEnd();
+}
+
+// this method processes SLIP data from MCU and converts to JSON
+// this method receives JSON from the browser, sends SLIP data to MCU
+static int ICACHE_FLASH_ATTR WEB_handleJSONRequest(HttpdConnData *connData)
+{
+	if( !flashConfig.slip_enable )
+	{
+		errorResponse(connData, 400, "Slip processing is disabled!");
+		return HTTPD_CGI_DONE;
+	}
+	CmdCallback* cb = cmdGetCbByName( WEB_CB );
+	if( cb == NULL )
+	{
+		errorResponse(connData, 500, "No MCU callback is registered!");
+		return HTTPD_CGI_DONE;
+	}
+	if( serbridgeInMCUFlashing() )
+	{
+		errorResponse(connData, 500, "Slip disabled at uploading program onto the MCU!");
+		return HTTPD_CGI_DONE;
+	}
+	
+	char reasonBuf[16];
+	int i;
+	int len = httpdFindArg(connData->getArgs, "reason", reasonBuf, sizeof(reasonBuf));
+	if( len < 0 )
+	{
+		errorResponse(connData, 400, "No reason specified!");
+			return HTTPD_CGI_DONE;
+	}
+	
+	RequestReason reason = INVALID;
+	for(i=0; i < sizeof(web_server_reasons)/sizeof(char *); i++)
+	{
+		if( os_strcmp( web_server_reasons[i], reasonBuf ) == 0 )
+			reason = (RequestReason)i;
+	}
+	
+	if( reason == INVALID )
+	{
+		errorResponse(connData, 400, "Invalid reason!");
+		return HTTPD_CGI_DONE;
+	}
+	
+	struct ArgumentBuffer argBuffer;
+	WEB_argInit( &argBuffer );
+	
+	switch(reason)
+	{
+		case BUTTON:
+			{
+				char id_buf[40];
+				
+				int id_len = httpdFindArg(connData->getArgs, "id", id_buf, sizeof(id_buf));
+				if( id_len <= 0 )
+				{
+					errorResponse(connData, 400, "No button ID specified!");
+					return HTTPD_CGI_DONE;
+				}
+				if( WEB_addArg(&argBuffer, id_buf, id_len) )
+				{
+					errorResponse(connData, 400, "Post too large!");
+					return HTTPD_CGI_DONE;
+				}
+			}
+			break;
+		case SUBMIT:
+			{
+				if( connData->post->received < connData->post->len )
+				{
+					errorResponse(connData, 400, "Post too large!");
+					return HTTPD_CGI_DONE;
+				}
+				
+				int bptr = 0;
+				
+				while( bptr < connData->post->len )
+				{
+					char * line = connData->post->buff + bptr;
+					
+					char * eo = os_strchr(line, '&' );
+					if( eo != NULL )
+					{
+						*eo = 0;
+						bptr = eo - connData->post->buff + 1;
+					}
+					else
+					{
+						eo = line + os_strlen( line );
+						bptr = connData->post->len;
+					}
+					
+					int len = os_strlen(line);
+					while( len >= 1 && ( line[len-1] == '\r' || line[len-1] == '\n' ))
+						len--;
+					line[len] = 0;
+					
+					char * val = os_strchr(line, '=');
+					if( val != NULL )
+					{
+						*val = 0;
+						char * name = line;
+						int vblen = os_strlen(val+1) * 2;
+						char value[vblen];
+						httpdUrlDecode(val+1, strlen(val+1), value, vblen);
+						
+						int namLen = os_strlen(name);
+						int valLen = os_strlen(value);
+						
+						char arg[namLen + valLen + 3];
+						int argPtr = 0;
+						arg[argPtr++] = (char)WEB_STRING;
+						os_strcpy( arg + argPtr, name );
+						argPtr += namLen;
+						arg[argPtr++] = 0;
+						os_strcpy( arg + argPtr, value );
+						argPtr += valLen;
+						
+						if( WEB_addArg(&argBuffer, arg, argPtr) )
+						{
+							errorResponse(connData, 400, "Post too large!");
+							return HTTPD_CGI_DONE;
+						}
+					}
+				}
+			}
+			break;
+		case LOAD:
+		case REFRESH:
+		default:
+			break;
+	}
+	
+	if( WEB_addArg(&argBuffer, NULL, 0) )
+	{
+		errorResponse(connData, 400, "Post too large!");
+		return HTTPD_CGI_DONE;
+	}
+	
+	os_printf("Web callback to MCU: %s\n", reasonBuf);
+	
+	WEB_sendArgBuffer(&argBuffer, connData, (uint32_t)cb->callback, reason );
+	
+	if( reason == SUBMIT )
+	{
+		httpdStartResponse(connData, 204);
+		httpdEndHeaders(connData);
+		return HTTPD_CGI_DONE;
+	}
+	
+	return HTTPD_CGI_MORE;
+}
+
+// this method receives SLIP data from MCU sends JSON to the browser
+static int ICACHE_FLASH_ATTR WEB_handleMCUResponse(HttpdConnData *connData, CmdRequest * response)
+{
+	char jsonBuf[1500];
+	int  jsonPtr = 0;
+	
+	
+	jsonBuf[jsonPtr++] = '{';
+	
+	int c = 2;
+	while( c++ < cmdGetArgc(response) )
+	{
+		int len = cmdArgLen(response);
+		char buf[len+1];
+		buf[len] = 0;
+		
+		cmdPopArg(response, buf, len);
+		
+		if(len == 0)
+			break; // last argument
+		
+		if( c > 3 ) // skip the first argument
+			jsonBuf[jsonPtr++] = ',';
+		
+		if( jsonPtr + 20 + len > sizeof(jsonBuf) )
+		{
+			errorResponse(connData, 500, "Response too large!");
+			return HTTPD_CGI_DONE;
+		}
+		
+		WebValueType type = (WebValueType)buf[0];
+		
+		int nameLen = os_strlen(buf+1);
+		jsonBuf[jsonPtr++] = '"';
+		os_memcpy(jsonBuf + jsonPtr, buf + 1, nameLen);
+		jsonPtr += nameLen;
+		jsonBuf[jsonPtr++] = '"';
+		jsonBuf[jsonPtr++] = ':';
+		
+		char * value = buf + 2 + nameLen;
+		
+		switch(type)
+		{
+			case WEB_NULL:
+				os_memcpy(jsonBuf + jsonPtr, "null", 4);
+				jsonPtr += 4;
+				break;
+			case WEB_INTEGER:
+				{
+					int v;
+					os_memcpy( &v, value, 4);
+					
+					char intbuf[20];
+					os_sprintf(intbuf, "%d", v);
+					os_strcpy(jsonBuf + jsonPtr, intbuf);
+					jsonPtr += os_strlen(intbuf);
+				}
+				break;
+			case WEB_BOOLEAN:
+				if( *value ) {
+					os_memcpy(jsonBuf + jsonPtr, "true", 4);
+					jsonPtr += 4;
+				} else {
+					os_memcpy(jsonBuf + jsonPtr, "false", 5);
+					jsonPtr += 5;
+				}
+				break;
+			case WEB_FLOAT:
+				{
+					float f;
+					os_memcpy( &f, value, 4);
+					
+					char intbuf[20];
+					os_sprintf(intbuf, "%f", f);
+					os_strcpy(jsonBuf + jsonPtr, intbuf);
+					jsonPtr += os_strlen(intbuf);
+				}
+				break;
+			case WEB_STRING:
+				jsonBuf[jsonPtr++] = '"';
+				while(*value)
+				{
+					if( *value == '\\' || *value == '"' )
+						jsonBuf[jsonPtr++] = '\\';
+					jsonBuf[jsonPtr++] = *(value++);
+				}
+				jsonBuf[jsonPtr++] = '"';
+				break;
+			case WEB_JSON:
+				os_memcpy(jsonBuf + jsonPtr, value, len - 2 - nameLen);
+				jsonPtr += len - 2 - nameLen;
+				break;
+		}
+	}
+	
+	jsonBuf[jsonPtr++] = '}';
+	
+	noCacheHeaders(connData, 200);
+	httpdHeader(connData, "Content-Type", "application/json");
+	
+	char cl[16];
+	os_sprintf(cl, "%d", jsonPtr);
+	httpdHeader(connData, "Content-Length", cl);
+	httpdEndHeaders(connData);
+	
+	httpdSend(connData, jsonBuf, jsonPtr);
+	return HTTPD_CGI_DONE;
+}
+
+// this method is responsible for the MCU <==JSON==> Browser communication
+int ICACHE_FLASH_ATTR WEB_CgiJsonHook(HttpdConnData *connData)
+{
+	if (connData->conn==NULL) return HTTPD_CGI_DONE; // Connection aborted. Clean up.
+	
+	void * cgiData = connData->cgiData;
+	
+	if( cgiData == NULL )
+	{
+		connData->cgiData = (void *)1; // indicate, that request was processed
+		return WEB_handleJSONRequest(connData);
+	}
+	
+	if( connData->cgiResponse != NULL ) // data from MCU
+		return WEB_handleMCUResponse(connData, (CmdRequest *)(connData->cgiResponse));
+	
+	return HTTPD_CGI_MORE;
+}
+
+// this method is called when MCU transmits WEB_DATA command
+void ICACHE_FLASH_ATTR WEB_Data(CmdPacket *cmd)
+{
+	CmdRequest req;
+	cmdRequest(&req, cmd);
+	
+	if (cmdGetArgc(&req) < 2) return;
+	
+	uint8_t ip[4];
+	cmdPopArg(&req, ip, 4);    // pop the IP address
+	
+	uint16_t port;
+	cmdPopArg(&req, &port, 2); // pop the HTTP port
+	
+	HttpdConnData * conn = httpdLookUpConn(ip, port);  // look up connection based on IP/port
+	if( conn != NULL && conn->cgi == WEB_CgiJsonHook ) // make sure that the right CGI handler is configured
+		httpdSetCGIResponse( conn, &req );
+	else
+		os_printf("WEB_DATA ignored as no valid HTTP connection found!\n");
+}
diff --git a/web-server/web-server.h b/web-server/web-server.h
new file mode 100644
index 0000000..0827229
--- /dev/null
+++ b/web-server/web-server.h
@@ -0,0 +1,37 @@
+#ifndef WEB_SERVER_H
+#define WEB_SERVER_H
+
+#include <esp8266.h>
+
+#include "httpd.h"
+#include "cmd.h"
+
+typedef enum
+{
+  LOAD=0,        // loading web-page content at the first time
+  REFRESH,       // loading web-page subsequently
+  BUTTON,        // HTML button pressed
+  SUBMIT,        // HTML form is submitted
+
+  INVALID=-1,
+} RequestReason;
+
+typedef enum
+{
+  WEB_STRING=0,  // the value is string
+  WEB_NULL,      // the value is NULL
+  WEB_INTEGER,   // the value is integer
+  WEB_BOOLEAN,   // the value is boolean
+  WEB_FLOAT,     // the value is float
+  WEB_JSON       // the value is JSON data
+} WebValueType;
+
+void   WEB_Init();
+
+char * WEB_UserPages();
+
+int    WEB_CgiJsonHook(HttpdConnData *connData);
+void   WEB_Data(CmdPacket *cmd);
+
+#endif /* WEB_SERVER_H */
+