diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
new file mode 100644
index 0000000..4007b47
--- /dev/null
+++ b/.github/workflows/build.yml
@@ -0,0 +1,76 @@
+name: Build
+
+on:
+  release:
+    types: [published]
+  workflow_dispatch:
+
+jobs:
+  build:
+    name: Build (${{ matrix.os }})
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - os: ubuntu-latest
+            script: build:linux
+            artifact: linux
+            paths: |
+              dist/*.AppImage
+              dist/*.deb
+              dist/*.rpm
+          - os: windows-latest
+            script: build:win
+            artifact: windows
+            paths: |
+              dist/*.exe
+          - os: macos-latest
+            script: build:mac
+            artifact: macos
+            paths: |
+              dist/*.dmg
+              dist/*.zip
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: '20'
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Build
+        run: npm run ${{ matrix.script }}
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Upload artifacts
+        uses: actions/upload-artifact@v7
+        with:
+          name: fsprinter-${{ matrix.artifact }}
+          path: ${{ matrix.paths }}
+          if-no-files-found: error
+
+  release:
+    name: Publish release
+    needs: build
+    if: github.event_name == 'release'
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - name: Download all artifacts
+        uses: actions/download-artifact@v7
+        with:
+          path: artifacts
+
+      - name: Create GitHub release
+        uses: softprops/action-gh-release@v3
+        with:
+          files: artifacts/**/*
+          generate_release_notes: true
diff --git a/.gitignore b/.gitignore
index e280281..076c22b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,9 +1,14 @@
 /nbproject/
 /node_modules/
 /vendor/
+/out/
+/dist/
 package-lock.json
 pos.txt
 out/
 ticket
 *.lock
-.DS_Store
\ No newline at end of file
+.DS_Store
+.idea
+.codex
+.claude
\ No newline at end of file
diff --git a/README.md b/README.md
index ce2fc3b..7d617ca 100644
--- a/README.md
+++ b/README.md
@@ -1,16 +1,63 @@
-# fsprinter
-Electron app to connect printers to FacturaScripts.
+# FSPrinter
+Electron app to connect printers to FacturaScripts a factura.city
 
-## Run from source
-```
+## Installation
+
+```bash
 npm install
+```
+
+## Development
+
+Run the application in development mode:
+
+```bash
 npm start
 ```
 
-## Build executable
+## Build
+
+The project uses **electron-builder** to create distributable packages.
+
+### Build for all platforms
+```bash
+npm run build
 ```
-npm run make
+
+### Build for specific platforms
+
+**Linux** (deb, rpm, AppImage):
+```bash
+npm run build:linux
 ```
 
+**Windows** (installer NSIS and portable):
+```bash
+npm run build:win
+```
+
+**macOS** (dmg and zip):
+```bash
+npm run build:mac
+```
+
+The compiled files will be generated in the `dist/` directory.
+
+## macOS: "The application is damaged"
+
+The macOS build is not signed with an Apple Developer ID, so Gatekeeper
+blocks it after download with a misleading "damaged" message. Remove the
+quarantine attribute to allow it to run:
+
+```bash
+xattr -dr com.apple.quarantine "/Applications/FSPrinter.app"
+```
+
+## Project Information
+
+- **Version:** 1.4.1
+- **Author:** Carlos García Gómez
+- **License:** LGPL-3.0
+
 ## Contact or feedback
-https://facturascripts.com/remote-printer
\ No newline at end of file
+https://facturascripts.com/plugins/tickets
diff --git a/main.js b/main.js
index d215b61..5c89e1d 100644
--- a/main.js
+++ b/main.js
@@ -1,23 +1,23 @@
-const { app, BrowserWindow, dialog, ipcMain } = require('electron');
+const { app, BrowserWindow, dialog, ipcMain, shell } = require('electron');
 const { exec } = require('child_process');
-const axios = require('axios');
-const fetch = require("node-fetch");
 const fs = require('fs');
 const os = require('os');
+const path = require('path');
 const settings = require('electron-settings');
 
+app.commandLine.appendSwitch('no-sandbox');
+
 var win = null;
 
 function createWindow() {
   win = new BrowserWindow({
-    width: 600,
-    height: 620,
+    width: 430,
+    height: 550,
     webPreferences: {
       contextIsolation: false,
-      enableRemoteModule: true,
       nodeIntegration: true
     }
-  });
+  })
 
   win.removeMenu();
   //win.webContents.openDevTools();
@@ -26,12 +26,17 @@ function createWindow() {
 
 function prinTesTicket(printerName) {
   var esc = '\x1B'; //ESC byte in hex notation
+  var gs = '\x1D'; //GS byte in hex notation
   var newLine = '\x0A'; //LF byte in hex notation
   var cmds = esc + "@"; //Initializes the printer (ESC @)
+
+  // Header
   cmds += esc + '!' + '\x38'; //Emphasized + Double-height + Double-width mode selected (ESC ! (8 + 16 + 32)) 56 dec => 38 hex
   cmds += 'PRUEBA'; //text to print
   cmds += newLine + newLine;
   cmds += esc + '!' + '\x00'; //Character font A selected (ESC ! 0)
+
+  // Sample items
   cmds += 'COOKIES                   5.00';
   cmds += newLine;
   cmds += 'MILK 65 Fl oz             3.78';
@@ -45,25 +50,91 @@ function prinTesTicket(printerName) {
   cmds += 'CASH TEND                10.00';
   cmds += newLine;
   cmds += 'CASH DUE                  0.78';
-  cmds += newLine + newLine + newLine + newLine;
+  cmds += newLine + newLine;
+
+  // Print barcode - Code128
+  cmds += esc + 'a' + '\x01'; // Center alignment
+  cmds += 'CODIGO DE BARRAS:';
+  cmds += newLine;
+  cmds += gs + 'h' + '\x50'; // Set barcode height to 80 dots
+  cmds += gs + 'w' + '\x02'; // Set barcode width to 2
+  cmds += gs + 'H' + '\x02'; // Print HRI (human readable) below barcode
+  cmds += gs + 'k' + '\x49' + '\x0D' + '1234567890123'; // CODE128 barcode with content
+  cmds += newLine + newLine;
+
+  // Print QR Code
+  cmds += 'CODIGO QR:';
+  cmds += newLine;
+  // QR Code: Model
+  cmds += gs + '(k' + '\x04\x00' + '1A2\x00'; // Function 165: Set model (49=1, 50=2)
+  // QR Code: Size
+  cmds += gs + '(k' + '\x03\x00' + '1C' + '\x08'; // Function 167: Set size to 8
+  // QR Code: Error correction level
+  cmds += gs + '(k' + '\x03\x00' + '1E0'; // Function 169: Error correction L
+  // QR Code: Store data
+  var qrData = 'https://megacity20.com';
+  var qrDataLength = qrData.length + 3;
+  var pL = String.fromCharCode(qrDataLength % 256);
+  var pH = String.fromCharCode(Math.floor(qrDataLength / 256));
+  cmds += gs + '(k' + pL + pH + '1P0' + qrData; // Function 180: Store data
+  // QR Code: Print
+  cmds += gs + '(k' + '\x03\x00' + '1Q0'; // Function 181: Print QR code
+  cmds += newLine + newLine;
 
-  fs.writeFile("ticket", cmds, function (err) {
+  // Reset alignment
+  cmds += esc + 'a' + '\x00'; // Left alignment
+  cmds += newLine + newLine;
+
+  // add cut command (ESC m - partial cut)
+  cmds += '\x1B\x6D' + newLine;
+
+  // add cash drawer open command (ESC p 0 55 121 - standard command)
+  cmds += '\x1B\x70\x30\x37\x79' + newLine;
+
+  const ticketPath = path.join(app.getPath('temp'), 'fsprinter_ticket');
+  fs.writeFile(ticketPath, cmds, function (err) {
     if (err) {
       return console.log(err);
     }
 
     prinTicket(printerName);
   });
+
+  // volcamos en consola la ruta del archivo
+  console.log('Ticket file path:', ticketPath);
 }
 
 function prinTicket(printerName) {
-  var printCmd = "lp -d " + printerName + " ticket";
+  const ticketPath = path.join(app.getPath('temp'), 'fsprinter_ticket');
+  let printCmd;
+
   if (os.platform() == 'win32') {
-    var fullPath = '"' + app.getAppPath() + "\\";
-    printCmd = fullPath + 'RawPrint.exe" "' + printerName + '" ticket';
+    // Get the resources path properly
+    let resourcesPath;
+    if (app.isPackaged) {
+      // When packaged, unpacked files are in app.asar.unpacked
+      resourcesPath = path.join(process.resourcesPath, 'app.asar.unpacked');
+    } else {
+      // In development, use the app path directly
+      resourcesPath = app.getAppPath();
+    }
+
+    const rawPrintPath = path.join(resourcesPath, 'RawPrint.exe');
+    printCmd = '"' + rawPrintPath + '" "' + printerName + '" "' + ticketPath + '"';
+  } else if (os.platform() == 'darwin') {
+    // macOS: usar lp con ruta absoluta
+    printCmd = 'lp -d "' + printerName + '" -o raw "' + ticketPath + '"';
+  } else {
+    // Linux
+    printCmd = 'lp -d "' + printerName + '" "' + ticketPath + '"';
   }
 
+  console.log('Print command:', printCmd);
+
   exec(printCmd, (error, stdout, stderr) => {
+    if(stdout) {
+      console.log(`stdout: ${stdout}`);
+    }
     if (error) {
       console.log(`error: ${error.message}`);
       dialog.showErrorBox("print error", error.message);
@@ -90,46 +161,45 @@ app.on('activate', () => {
   }
 })
 
-ipcMain.on('print-test', (event, arg) => {
-  prinTesTicket(arg);
-  event.reply('print-test', 'ok');
+ipcMain.handle('get-printers', async () => {
+  return await win.webContents.getPrintersAsync();
 })
 
-ipcMain.on('print-2017', (event, arg) => {
-  console.log('print-2017');
+ipcMain.on('open-external', (event, url) => {
+  shell.openExternal(url);
+})
 
-  fs.writeFile("ticket", arg, function (err) {
-    if (err) {
-      return console.log(err);
-    }
+ipcMain.on('reload-window', () => {
+  if (win) win.reload();
+})
 
-    prinTicket(settings.getSync('printer.name'));
-  });
+ipcMain.handle('settings-get', async (event, key) => {
+  return await settings.get(key);
+})
 
-  event.reply('print-2017', 'ok');
+ipcMain.handle('settings-set', async (event, key, value) => {
+  return await settings.set(key, value);
 })
 
-ipcMain.on('print-2020', (event, element) => {
-  console.log('print-2020');
+ipcMain.handle('settings-has', async (event, key) => {
+  return await settings.has(key);
+})
 
-  var ticket = element.text;
+ipcMain.handle('settings-unset', async () => {
+  return await settings.unset();
+})
 
-  // apply cut command
-  var cutCode = settings.getSync('2020.cut') ?? '27.105';
-  var cutComm = cutCode.split('.');
-  if (cutComm.length > 0 && element.cortarpapel) {
-    ticket += String.fromCharCode(...cutComm);
-  }
+ipcMain.on('print-test', (event, arg) => {
+  prinTesTicket(arg);
+  event.reply('print-test', 'ok');
+})
 
-  // apply open command
-  var openCode = settings.getSync('2020.open') ?? '27.112.48';
-  var openComm = openCode.split('.');
-  if (openComm.length > 0 && element.abrircajon) {
-    ticket += String.fromCharCode(...openComm);
-  }
+ipcMain.on('send-to-printer', (event, arg) => {
+  console.log('send-to-printer');
 
-  // print
-  fs.writeFile("ticket", ticket, function (err) {
+  const ticketPath = path.join(app.getPath('temp'), 'fsprinter_ticket');
+  var text = '\x1B' + '@' + arg;
+  fs.writeFile(ticketPath, text, function (err) {
     if (err) {
       return console.log(err);
     }
@@ -137,22 +207,5 @@ ipcMain.on('print-2020', (event, element) => {
     prinTicket(settings.getSync('printer.name'));
   });
 
-  event.reply('print-2020', 'ok');
+  event.reply('send-to-printer', 'ok');
 })
-
-// http server
-const http = require('http');
-const requestListener = function (req, res) {
-  res.writeHead(200);
-  res.end('fsprinter 0.6.1');
-  console.log('http request: ' + req.url);
-
-  // send a message to the main window
-  if (req.url.substring(0, 11) == '/?terminal=') {
-    win.webContents.send('http-request-2017', req.url.substring(2));
-  } else if (req.url.substring(0, 12) == '/?documento=') {
-    win.webContents.send('http-request-2020', req.url.substring(12));
-  }
-}
-const server = http.createServer(requestListener);
-server.listen(8089);
\ No newline at end of file
diff --git a/package.json b/package.json
index f0edfbe..129b2b2 100644
--- a/package.json
+++ b/package.json
@@ -1,56 +1,73 @@
 {
   "name": "fsprinter",
-  "version": "0.6.1",
-  "description": "Electron app to connect printers to FacturaScripts",
+  "version": "1.4.0",
+  "description": "Electron app to connect printers to FacturaScripts and factura.city",
   "main": "main.js",
   "scripts": {
-    "start": "electron-forge start",
-    "package": "electron-forge package",
-    "make": "electron-forge make"
+    "start": "electron . --no-sandbox",
+    "build": "electron-builder",
+    "build:linux": "electron-builder --linux",
+    "build:win": "electron-builder --win",
+    "build:mac": "electron-builder --mac"
   },
   "keywords": [],
-  "author": "Carlos García Gómez",
+  "author": {
+    "name": "Carlos García Gómez",
+    "email": "carlos@facturascripts.com"
+  },
   "license": "LGPL-3.0",
   "devDependencies": {
-    "@electron-forge/cli": "^6.0.0-beta.54",
-    "@electron-forge/maker-deb": "^6.0.0-beta.54",
-    "@electron-forge/maker-rpm": "^6.0.0-beta.54",
-    "@electron-forge/maker-squirrel": "^6.0.0-beta.54",
-    "@electron-forge/maker-zip": "^6.0.0-beta.54",
-    "electron": "^11.2.3"
+    "electron": "^42",
+    "electron-builder": "^26.15.6"
   },
   "dependencies": {
-    "axios": "^0.21.0",
-    "bootstrap": "^5.0.0",
+    "axios": "^1.12.2",
+    "bootstrap": "^5.3.0",
+    "bootstrap-icons": "^1.11.0",
     "electron-settings": "^4.0.2",
-    "electron-squirrel-startup": "^1.0.0",
     "node-fetch": "^2.6.1"
   },
-  "config": {
-    "forge": {
-      "packagerConfig": {},
-      "makers": [
-        {
-          "name": "@electron-forge/maker-squirrel",
-          "config": {
-            "name": "fsprinter"
-          }
-        },
-        {
-          "name": "@electron-forge/maker-zip",
-          "platforms": [
-            "darwin"
-          ]
-        },
-        {
-          "name": "@electron-forge/maker-deb",
-          "config": {}
-        },
-        {
-          "name": "@electron-forge/maker-rpm",
-          "config": {}
-        }
+  "build": {
+    "appId": "com.megacity20.fsprinter",
+    "productName": "FSPrinter",
+    "directories": {
+      "output": "dist"
+    },
+    "files": [
+      "**/*",
+      "!node_modules/**/*",
+      "node_modules/**/*"
+    ],
+    "asarUnpack": [
+      "node_modules/**/*",
+      "RawPrint.exe"
+    ],
+    "linux": {
+      "target": [
+        "deb",
+        "rpm",
+        "AppImage"
+      ],
+      "category": "Office"
+    },
+    "win": {
+      "target": [
+        "nsis",
+        "portable"
       ]
+    },
+    "mac": {
+      "target": [
+        "dmg",
+        "zip"
+      ],
+      "category": "public.app-category.productivity",
+      "hardenedRuntime": false,
+      "gatekeeperAssess": false,
+      "identity": null
     }
+  },
+  "allowScripts": {
+    "electron-winstaller@5.4.0": true
   }
 }
diff --git a/src/index.html b/src/index.html
index 08c8bce..0c6ed79 100644
--- a/src/index.html
+++ b/src/index.html
@@ -1,150 +1,73 @@
 <!DOCTYPE html>
 <html>
-
 <head>
     <meta charset="UTF-8">
-    <title>fsprinter 0.6.1</title>
+    <title>fsprinter 1.4.0</title>
     <meta http-equiv="Content-Security-Policy" content="script-src 'self' 'unsafe-inline';" />
     <link rel="stylesheet" href="../node_modules/bootstrap/dist/css/bootstrap.min.css" />
+    <link rel="stylesheet" href="../node_modules/bootstrap-icons/font/bootstrap-icons.css" />
 </head>
-
 <body>
-    <div class="container mb-4 mt-4">
+    <div class="container">
         <div class="row">
             <div class="col">
-                <h1 class="h3 mb-1">Impresora</h1>
-            </div>
-        </div>
-        <div class="row">
-            <div class="col-sm-8">
-                <div class="mb-3">
+                <h1 class="h3 mt-3 mb-1"><i class="bi bi-printer me-2"></i>Impresora</h1>
+                <div class="mb-2">
                     <select class="form-select" id="printer_list" name="printer"></select>
                     <div class="form-text">Selecciona la impresora de tickets que quieras utilizar.</div>
                 </div>
             </div>
+        </div>
+        <div class="row">
             <div class="col">
-                <div class="mb-3">
-                    <button class="btn btn-primary" onclick="prinTest();">Seleccionar</button>
+                <div class="d-grid gap-2 mb-2">
+                    <button class="btn btn-secondary" onclick="testPrinter();"><i class="bi bi-printer me-2"></i>Probar impresora</button>
                 </div>
             </div>
-        </div>
-    </div>
-    <!-- Nav tabs -->
-    <ul class="nav nav-tabs nav-fill" role="tablist">
-        <li class="nav-item" role="presentation">
-            <button class="nav-link active" id="fs2020-tab" data-bs-toggle="tab" data-bs-target="#fs2020" type="button"
-                role="tab" aria-controls="fs2020" aria-selected="true">
-                2021
-            </button>
-        </li>
-        <li class="nav-item" role="presentation">
-            <button class="nav-link" id="fs2017-tab" data-bs-toggle="tab" data-bs-target="#fs2017" type="button"
-                role="tab" aria-controls="fs2017" aria-selected="false">
-                2017
-            </button>
-        </li>
-    </ul>
-    <!-- Tab panes -->
-    <div class="tab-content">
-        <div class="tab-pane active" id="fs2020" role="tabpanel" aria-labelledby="fs2020-tab">
-            <div class="container mt-4">
-                <div class="row">
-                    <div class="col-sm-8">
-                        <div class="mb-3">
-                            <input type="text" class="form-control" id="url_2020" placeholder="https://" />
-                            <div class="form-text">
-                                Para conectar con FacturaScripts 2021 escribe aquí la url donde tengas FacturaScripts.
-                            </div>
-                        </div>
-                    </div>
-                    <div class="col-sm-4">
-                        <div class="mb-3">
-                            <input type="number" min="2" max="99" step="1" class="form-control" id="timer_2020" />
-                            <div class="form-text">
-                                Comprobar cada X segundos.
-                            </div>
-                        </div>
-                    </div>
-                    <div class="col-sm-12">
-                        <div class="mb-3">
-                            <div class="input-group">
-                                <input type="text" class="form-control" id="key_2020" placeholder="Clave de API" />
-                                <button class="btn btn-primary" type="submit" onclick="test2020();">Comprobar</button>
-                            </div>
-                            <div class="form-text">
-                                También necesitas una clave de API. Puedes crearla desde FacturaScripts,
-                                en el menú Administrador &gt; Panel de control &gt; API keys.
-                            </div>
-                        </div>
-                    </div>
-                    <div class="col-sm-6">
-                        <div class="mb-3">
-                            <input type="text" class="form-control" id="cut_2020" placeholder="Comando de corte" />
-                            <div class="form-text">
-                                Comando de <b>corte</b> para la impresora. Ejemplo: 27.105
-                            </div>
-                        </div>
-                    </div>
-                    <div class="col-sm-6">
-                        <div class="mb-3">
-                            <input type="text" class="form-control" id="open_2020" placeholder="Comando de apertura" />
-                            <div class="form-text">
-                                Comando de <b>apertura de cajón</b> para la impresora. Ejemplo: 27.112.48
-                            </div>
-                        </div>
-                    </div>
+            <div class="col">
+                <div class="d-grid gap-2 mb-3">
+                    <button class="btn btn-primary" onclick="testConnection();"><i class="bi bi-wifi me-2"></i>Probar conexión</button>
                 </div>
             </div>
         </div>
-        <div class="tab-pane" id="fs2017" role="tabpanel" aria-labelledby="fs2017-tab">
-            <div class="container mt-4">
-                <div class="row">
-                    <div class="col-sm-12">
-                        <div class="mb-3">
-                            <div class="input-group">
-                                <input type="text" class="form-control" id="url_2017" placeholder="https://" />
-                                <button class="btn btn-primary" type="submit" onclick="test2017();">Comprobar</button>
-                            </div>
-                            <div class="form-text">
-                                Para conectar con FacturaScripts 2017 escribe aquí la url donde tengas FacturaScripts.
-                            </div>
-                        </div>
-                    </div>
+        <div class="row">
+            <div class="col">
+                <div class="form-floating mb-2 position-relative">
+                    <input type="text" class="form-control pe-5" id="api_url" placeholder="https://" />
+                    <label for="api_url">URL</label>
+                    <button type="button" class="btn btn-sm btn-link text-danger position-absolute top-50 end-0 translate-middle-y me-2 p-1 d-none" id="reset_btn" onclick="resetSettings();" title="Resetear configuración">
+                        <i class="bi bi-trash"></i>
+                    </button>
                 </div>
-                <div class="row">
-                    <div class="col-sm-12">
-                        <h2 class="h4 mt-3">Opcional</h2>
-                        <p class="form-text">
-                            Si tienes problemas al imprimir, puedes configurar aquí la impresión de todos
-                            los tickets pendientes de un terminal concreto.
-                        </p>
-                    </div>
-                    <div class="col-sm-6">
-                        <div class="mb-3">
-                            <input type="number" min="0" max="99" step="1" class="form-control" id="terminal_2017" />
-                            <div class="form-text">
-                                Número de terminal.
-                            </div>
-                        </div>
-                    </div>
-                    <div class="col-sm-6">
-                        <div class="mb-3">
-                            <input type="number" min="2" max="99" step="1" class="form-control" id="timer_2017" />
-                            <div class="form-text">
-                                Comprobar cada X segundos.
-                            </div>
-                        </div>
-                    </div>
+                <div class="form-floating mb-2">
+                    <input type="text" class="form-control" id="api_key" placeholder="Clave de API" />
+                    <label for="api_key">API key</label>
+                </div>
+                <div class="form-floating mb-2">
+                    <input type="number" class="form-control" id="printer_len" min="0" />
+                    <label for="printer_len">Caracteres por línea</label>
+                </div>
+                <div class="form-floating mb-2">
+                    <select class="form-select" id="poll_interval" onchange="onPollIntervalChange();">
+                        <option value="0">Solo WebSocket</option>
+                        <option value="30">30 segundos</option>
+                        <option value="60">1 minuto</option>
+                        <option value="120">2 minutos</option>
+                        <option value="300">5 minutos</option>
+                        <option value="600">10 minutos</option>
+                        <option value="1800">30 minutos</option>
+                    </select>
+                    <label for="poll_interval">Comprobar periódicamente</label>
                 </div>
             </div>
         </div>
     </div>
-
-    <!-- Bottom bar -->
-    <nav class="navbar fixed-bottom navbar-light bg-warning">
-        <div class="container-fluid">
-            <span class="navbar-text">
-                Si cierras esta aplicación no podrás imprimir tickets.
+    
+    <!-- Bottom bar: global status -->
+    <nav class="navbar fixed-bottom navbar-light bg-secondary" id="global_status_bar" title="">
+        <div class="container-fluid justify-content-center">
+            <span class="navbar-text text-white" id="global_status_text">
+                <i class="bi bi-circle-fill me-2"></i>Iniciando…
             </span>
         </div>
     </nav>
@@ -152,5 +75,4 @@ <h2 class="h4 mt-3">Opcional</h2>
     <script src="../node_modules/bootstrap/dist/js/bootstrap.bundle.min.js"></script>
     <script src="index.js"></script>
 </body>
-
-</html>
\ No newline at end of file
+</html>
diff --git a/src/index.js b/src/index.js
index e4a2090..ac7cd0d 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,226 +1,436 @@
-const { ipcRenderer, remote } = require("electron");
+const { ipcRenderer } = require("electron");
 const axios = require('axios');
-const printers = remote.getCurrentWebContents().getPrinters();
-const settings = require('electron-settings');
+const crypto = require('crypto');
 
-var printLock = false;
+function settingsGet(key) {
+  return ipcRenderer.invoke('settings-get', key);
+}
+function settingsSet(key, value) {
+  return ipcRenderer.invoke('settings-set', key, value);
+}
+function settingsHas(key) {
+  return ipcRenderer.invoke('settings-has', key);
+}
+function settingsUnset() {
+  return ipcRenderer.invoke('settings-unset');
+}
+
+let wsConnection = null;
+let wsReconnectTimeout = null;
+let wsConnectionAttempt = 0;
+let connectionPingInFlight = false;
+let connectionPingQueued = false;
+let pollIntervalTimer = null;
+
+const globalState = {
+  ws: 'disconnected',
+  api: 'idle',
+  apiMessage: '',
+  apiTime: ''
+};
+
+function wsStateLabel(s) {
+  switch (s) {
+    case 'connected': return 'conectado';
+    case 'connecting': return 'conectando…';
+    case 'error': return 'error';
+    default: return 'desconectado';
+  }
+}
 
-async function connect2017(params) {
-  if (false == settings.hasSync('2017.url') || printLock) {
+function apiStateLabel(s, time, message) {
+  switch (s) {
+    case 'ok': return 'OK (' + time + ')';
+    case 'error': return 'error (' + time + ') ' + (message || '');
+    default: return 'sin actividad';
+  }
+}
+
+function renderGlobalStatus() {
+  const bar = document.getElementById('global_status_bar');
+  const text = document.getElementById('global_status_text');
+  if (!bar || !text) {
     return;
   }
 
-  printLock = true;
-  var url2017 = settings.getSync('2017.url') + '/api.php?v=2&f=remote_printer';
-  if (params == '') {
-    url2017 += '&terminal=' + settings.getSync('2017.terminal');
+  const ws = globalState.ws;
+  const api = globalState.api;
+  const urlEl = document.getElementById('api_url');
+  const hasUrl = urlEl && urlEl.value.trim().length > 0;
+
+  let bg = 'bg-secondary';
+  let label = 'Iniciando…';
+
+  if (!hasUrl) {
+    bg = 'bg-warning';
+    label = 'Rellena la URL de la API para empezar';
+  } else if (api === 'error') {
+    bg = 'bg-danger';
+    label = 'Error de API — no se imprimirán tickets';
+  } else if (ws === 'connected') {
+    bg = 'bg-success';
+    label = 'Listo para imprimir — no cierres esta ventana';
+  } else if (ws === 'connecting') {
+    bg = 'bg-warning';
+    label = 'Conectando…';
+  } else if (ws === 'error') {
+    bg = 'bg-danger';
+    label = 'Sin conexión — no se imprimirán tickets';
   } else {
-    url2017 += '&' + params;
+    bg = 'bg-secondary';
+    label = 'Desconectado — configura la API para imprimir';
   }
 
+  bar.className = 'navbar fixed-bottom navbar-light ' + bg;
+  text.innerHTML = '<i class="bi bi-circle-fill me-2"></i>' + label;
+  bar.title = 'WebSocket: ' + wsStateLabel(ws)
+    + '  ·  API: ' + apiStateLabel(api, globalState.apiTime, globalState.apiMessage);
+}
+
+function updateWebSocketStatus(status) {
+  globalState.ws = status;
+  renderGlobalStatus();
+}
+
+function updateApiStatus(status, message) {
+  globalState.api = status;
+  globalState.apiMessage = message || '';
+  globalState.apiTime = (status === 'idle') ? '' : new Date().toLocaleTimeString();
+  renderGlobalStatus();
+}
+
+async function connectionPingOnce() {
+  var apiUrl = document.getElementById("api_url").value.trim();
+  var apiKey = document.getElementById("api_key").value.trim();
+
   try {
-    const response = await fetch(url2017);
-    const ticket = await response.text();
-    if (response.status == 200 && ticket.trim().length > 0) {
-      ipcRenderer.send('print-2017', ticket);
-    } else {
-      console.log(url2017);
-      console.log(response.status);
-      console.log(ticket);
-      console.log(ticket.trim().length);
+    const apiClient = await axios.create({ baseURL: apiUrl, headers: { Token: apiKey } });
+
+    // Get printer ID first
+    const printerId = await getPrinterId(apiClient, apiKey);
+    if (printerId) {
+      await printPendingTickets(apiClient, printerId);
     }
+    updateApiStatus('ok');
   } catch (err) {
-    alert('La conexión con fs2017 falló: ' + err);
+    console.error('connectionPing failed:', err);
+    updateApiStatus('error', err && err.message ? err.message : String(err));
   }
-
-  printLock = false;
 }
 
-async function connect2020(params) {
-  if (false == settings.hasSync('2020.url') || printLock) {
+async function connectionPing() {
+  if (connectionPingInFlight) {
+    connectionPingQueued = true;
     return;
   }
 
-  printLock = true;
+  connectionPingInFlight = true;
+
   try {
-    const apiClient = await axios.create({
-      baseURL: settings.getSync('2020.url'),
-      headers: {
-        Token: settings.getSync('2020.key')
-      }
-    });
-    const response = await apiClient.get('/api/3/ticketes/' + params);
-    if (0 < response.data.text.trim().length) {
-      ipcRenderer.send('print-2020', response.data);
-      apiClient.delete('/api/3/ticketes/' + response.data.coddocument);
+    do {
+      connectionPingQueued = false;
+      await connectionPingOnce();
+    } while (connectionPingQueued);
+  } finally {
+    connectionPingInFlight = false;
+  }
+}
+
+async function getPrinterId(apiClient, apiKey) {
+  const resPrinters = await apiClient.get('/api/3/ticketprinteres');
+
+  for (const item of resPrinters.data) {
+    if (item.apikey == apiKey) {
+      return item.id;
     }
-  } catch (err) {
-    alert('La conexión con fs falló' + err);
   }
-  printLock = false;
+  return null;
 }
 
-function prinTest() {
-  var printerName = document.getElementById("printer_list").value;
-  settings.setSync('printer', { name: printerName });
-  ipcRenderer.send('print-test', printerName);
+async function printPendingTickets(apiClient, printerId) {
+  // get the latest tickets filtered by printer ID
+  const resTickets = await apiClient.get('/api/3/ticketes?filter[printed]=0&filter[idprinter]=' + printerId);
+  console.log(resTickets);
+
+  // find the apikey in resPrinters and update lastactivity
+  for (const item of resTickets.data) {
+    if (item.appversion > 1.0) {
+      alert('Por favor, descarga la nueva versión de la app');
+      // open a browser window with the app url https://megacity20.com/support/59
+      ipcRenderer.send('open-external', 'https://megacity20.com/support/59');
+    } else if (item.base64) {
+      ipcRenderer.send('send-to-printer', atob(item.body));
+    } else {
+      ipcRenderer.send('send-to-printer', item.body);
+    }
+
+    // set printed to true
+    const resPut = await apiClient.put('/api/3/ticketes/' + item.id, 'printed=1');
+  }
+
+  // get the printer list
+  const resPrinters = await apiClient.get('/api/3/ticketprinteres');
+
+  // find the apikey in resPrinters and update lastactivity and len
+  for (const item of resPrinters.data) {
+    if (item.apikey == document.getElementById("api_key").value) {
+      // get the current date YYYY-MM-DD HH:MM:SS format
+      var date = new Date();
+      var dateStr = date.getFullYear() + '-' + (date.getMonth() + 1) + '-' + date.getDate()
+        + ' ' + date.getHours() + ':' + date.getMinutes() + ':' + date.getSeconds();
+
+      // send put request
+      var printerLen = document.getElementById("printer_len").value;
+      const resPut = await apiClient.put(
+        '/api/3/ticketprinteres/' + item.id,
+        'lastactivity=' + dateStr + '&linelen=' + printerLen
+      );
+    }
+  }
 }
 
-function test2017() {
-  var url2017 = document.getElementById("url_2017").value;
-  if (url2017.substring(0, 7) != 'http://' && url2017.substring(0, 8) != 'https://') {
+async function testConnection() {
+  var printerName = document.getElementById("printer_list").value;
+  var apiUrl = document.getElementById("api_url").value.trim();
+  var apiKey = document.getElementById("api_key").value.trim();
+  var printerLen = document.getElementById("printer_len").value;
+
+  if (apiUrl.substring(0, 7) != 'http://' && apiUrl.substring(0, 8) != 'https://') {
     alert('URL incorrecta');
     return false;
+  } else if (0 == apiKey.length) {
+    alert('Se necesita una API key');
+    return false;
   }
 
-  if (url2017.substring(url2017.length - 8) == '/api.php') {
-    url2017 = url2017.substring(0, url2017.length - 8);
-  }
+  try {
+    const apiClient = await axios.create({ baseURL: apiUrl, headers: { Token: apiKey } });
+    const resPrinters = await apiClient.get('/api/3/ticketprinteres');
+    console.log(resPrinters);
+
+    // find the apikey in resPrinters and update lastactivity and len
+    for (const item of resPrinters.data) {
+      if (item.apikey == apiKey) {
+        // get the current date YYYY-MM-DD HH:MM:SS format
+        var date = new Date();
+        var dateStr = date.getFullYear() + '-' + (date.getMonth() + 1) + '-'
+          + date.getDate() + ' ' + date.getHours() + ':' + date.getMinutes() + ':' + date.getSeconds();
 
-  var terminal2017 = document.getElementById("terminal_2017").value ?? '1';
-  var timer2017 = document.getElementById("timer_2017").value ?? '10';
+        // send put request
+        const resPut = await apiClient.put(
+          '/api/3/ticketprinteres/' + item.id,
+          'lastactivity=' + dateStr + '&linelen=' + printerLen
+        );
+        console.log(resPut);
 
-  fetch(url2017 + '/api.php?v=2').then(function (response) {
-    response.text().then(function (body) {
-      if (body != 'Ninguna funcion ejecutada.') {
-        alert('No se ha detectado un FacturaScripts 2017 en esta url');
-        return false;
+        // handle success
+        await settingsSet('printer', { name: printerName, len: printerLen });
+        await settingsSet('api', { url: apiUrl, key: apiKey });
+        alert('La conexión funciona correctamente');
+        await printPendingTickets(apiClient, item.id);
+        connectWebSocket();
       }
+    }
+  } catch (err) {
+    alert('La conexión falló');
+    console.log(err);
+  }
 
-      settings.setSync('2017', { url: url2017, terminal: terminal2017, timer: timer2017 });
-      alert('Datos guardados correctamente');
-      setTimer2017();
-    });
-    return false;
-  });
+  return false;
 }
 
-function test2020() {
-  var url2020 = document.getElementById("url_2020").value;
-  if (url2020.substring(0, 7) != 'http://' && url2020.substring(0, 8) != 'https://') {
-    alert('URL incorrecta');
-    return false;
+function applyPollInterval() {
+  if (pollIntervalTimer) {
+    clearInterval(pollIntervalTimer);
+    pollIntervalTimer = null;
   }
 
-  var key2020 = document.getElementById("key_2020").value;
-  if (0 == key2020.length) {
-    alert('Se necesita una API key');
-    return false;
+  const seconds = parseInt(document.getElementById("poll_interval").value, 10) || 0;
+  if (seconds > 0) {
+    pollIntervalTimer = setInterval(connectionPing, seconds * 1000);
   }
+}
 
-  var cut2020 = document.getElementById("cut_2020").value ?? '';
-  var open2020 = document.getElementById("open_2020").value ?? '';
-  var timer2020 = document.getElementById("timer_2020").value ?? '10';
+async function onPollIntervalChange() {
+  const seconds = parseInt(document.getElementById("poll_interval").value, 10) || 0;
+  await settingsSet('poll.interval', seconds);
+  applyPollInterval();
+}
 
-  const apiClient = axios.create({
-    baseURL: url2020,
-    headers: {
-      Token: key2020
-    }
+async function testPrinter() {
+  await settingsSet('printer', {
+    name: document.getElementById("printer_list").value,
+    len: document.getElementById("printer_len").value
   });
-  apiClient.get('/api/3').then(function (response) {
-    // handle success
-    settings.setSync('2020', { url: url2020, key: key2020, cut: cut2020, open: open2020, timer: timer2020 });
-    alert('Datos guardados correctamente');
-    setTimer2020();
-  })
-    .catch(function (error) {
-      // handle error
-      console.log(error);
-      alert('Error al conectar');
-    });
+  ipcRenderer.send('print-test', document.getElementById("printer_list").value);
 }
 
-// timer 2017 functions
-function timer2017() {
-  connect2017('');
+function normalizeApiUrl(rawUrl) {
+  const url = new URL(rawUrl.trim());
+  url.protocol = url.protocol.toLowerCase();
+  url.hostname = url.hostname.toLowerCase();
+  if (
+    (url.protocol === 'http:' && url.port === '80') ||
+    (url.protocol === 'https:' && url.port === '443')
+  ) {
+    url.port = '';
+  }
+  let result = url.protocol + '//' + url.host + url.pathname;
+  if (result.endsWith('/')) {
+    result = result.slice(0, -1);
+  }
+  return result;
 }
 
-function setTimer2017() {
-  if (settings.hasSync('2017.url') &&
-    parseInt(document.getElementById("terminal_2017").value) > 0 &&
-    parseInt(document.getElementById("timer_2017").value) > 0) {
-    var seconds = parseInt(document.getElementById("timer_2017").value);
-    var myTimer2017 = setInterval(timer2017, seconds * 1000);
-  }
+function isLocalHostname(hostname) {
+  return ['localhost', '127.0.0.1', '[::1]', '::1'].includes(hostname);
 }
 
-// timer 2020 functions
-function timer2020() {
-  if (false == settings.hasSync('2020.url') || printLock) {
-    return;
+function connectWebSocket() {
+  const rawApiUrl = document.getElementById("api_url").value.trim();
+  const apiKey = document.getElementById("api_key").value.trim();
+
+  if (wsReconnectTimeout) {
+    clearTimeout(wsReconnectTimeout);
+    wsReconnectTimeout = null;
   }
 
-  printLock = true;
-  const apiClient = axios.create({
-    baseURL: settings.getSync('2020.url'),
-    headers: {
-      Token: settings.getSync('2020.key')
+  if (!rawApiUrl) {
+    if (wsConnection) {
+      wsConnection._intentionalClose = true;
+      wsConnection.close();
+      wsConnection = null;
     }
-  });
+    updateWebSocketStatus('disconnected');
+    return;
+  }
 
-  /// get all tickets
-  apiClient.get('/api/3/ticketes').then(function (response) {
-    response.data.forEach(element => {
-      ipcRenderer.send('print-2020', element);
-
-      /// delete
-      apiClient.delete('/api/3/ticketes/' + element.coddocument);
-    });
-  }).catch(function (error) {
-    // handle error
-    console.log(error);
-  });
-  printLock = false;
-}
+  let apiUrl;
+  let hostname;
+  try {
+    apiUrl = normalizeApiUrl(rawApiUrl);
+    hostname = new URL(apiUrl).hostname;
+  } catch (err) {
+    console.error('Invalid API URL, cannot open WebSocket:', err);
+    updateWebSocketStatus('error');
+    return;
+  }
+
+  // For local URLs the host is ambiguous across installations, so disambiguate
+  // with the API key. The server must apply the same rule.
+  const channelInput = isLocalHostname(hostname) ? apiUrl + ':' + apiKey : apiUrl;
+  const channel = crypto.createHash('md5').update(channelInput).digest('hex');
+  const wsUrl = `wss://ai.factura.city/mc20printer/${channel}`;
+
+  console.log('Connecting to WebSocket:', wsUrl);
+
+  // Close existing connection if any
+  if (wsConnection) {
+    wsConnection._intentionalClose = true;
+    wsConnection.close();
+  }
+
+  updateWebSocketStatus('connecting');
+
+  try {
+    const socket = new WebSocket(wsUrl);
+    const attempt = ++wsConnectionAttempt;
+    socket._intentionalClose = false;
+    wsConnection = socket;
 
-function setTimer2020() {
-  if (settings.hasSync('2020.url') && parseInt(document.getElementById("timer_2020").value) > 0) {
-    var seconds = parseInt(document.getElementById("timer_2020").value);
-    var myTimer2020 = setInterval(timer2020, seconds * 1000);
+    socket.onopen = function() {
+      if (wsConnection !== socket || attempt !== wsConnectionAttempt) {
+        socket._intentionalClose = true;
+        socket.close();
+        return;
+      }
+
+      console.log('WebSocket connected');
+      updateWebSocketStatus('connected');
+    };
+
+    socket.onmessage = function(event) {
+      if (wsConnection !== socket || attempt !== wsConnectionAttempt) {
+        return;
+      }
+
+      console.log('WebSocket message received:', event.data);
+      // When a message is received, fetch and print pending tickets
+      connectionPing();
+    };
+
+    socket.onerror = function(error) {
+      if (wsConnection !== socket || attempt !== wsConnectionAttempt) {
+        return;
+      }
+
+      console.error('WebSocket error:', error);
+      updateWebSocketStatus('error');
+    };
+
+    socket.onclose = function() {
+      if (wsConnection !== socket || attempt !== wsConnectionAttempt) {
+        console.log('Ignoring close event from stale WebSocket');
+        return;
+      }
+
+      wsConnection = null;
+      console.log('WebSocket disconnected');
+      updateWebSocketStatus('disconnected');
+
+      // Only reconnect if the close was not intentional
+      if (!socket._intentionalClose) {
+        console.log('Reconnecting in 5 seconds...');
+        wsReconnectTimeout = setTimeout(connectWebSocket, 5000);
+      } else {
+        console.log('Intentional close, not reconnecting');
+      }
+    };
+  } catch (err) {
+    wsConnection = null;
+    console.error('Failed to connect to WebSocket:', err);
+    updateWebSocketStatus('error');
   }
 }
 
 // load printer list
-var selectedPrinter = settings.getSync('printer.name');
-printers.map((item, index) => {
-  if (item.name == selectedPrinter) {
-    document.getElementById("printer_list").innerHTML +=
-      '<option value="' + item.name + '" selected="">' + item.name + '</option>';
-  } else {
-    document.getElementById("printer_list").innerHTML +=
-      '<option value="' + item.name + '">' + item.name + '</option>';
-  }
+ipcRenderer.invoke('get-printers').then(async (printers) => {
+  var selectedPrinter = await settingsGet('printer.name');
+  printers.map((item) => {
+    if (item.name == selectedPrinter) {
+      document.getElementById("printer_list").innerHTML +=
+        '<option value="' + item.name + '" selected="">' + item.name + '</option>';
+    } else {
+      document.getElementById("printer_list").innerHTML +=
+        '<option value="' + item.name + '">' + item.name + '</option>';
+    }
+  });
 });
 
 // load preferences
-if (settings.hasSync('2017.url')) {
-  document.getElementById("url_2017").value = settings.getSync('2017.url');
-  document.getElementById("terminal_2017").value = settings.getSync('2017.terminal') ?? '1';
-  document.getElementById("timer_2017").value = settings.getSync('2017.timer') ?? '10';
-  setTimer2017();
-} else {
-  document.getElementById("terminal_2017").value = '1';
-  document.getElementById("timer_2017").value = '10';
-}
-
-if (settings.hasSync('2020.url')) {
-  document.getElementById("url_2020").value = settings.getSync('2020.url');
-  document.getElementById("timer_2020").value = settings.getSync('2020.timer') ?? '10';
-  document.getElementById("key_2020").value = settings.getSync('2020.key');
-  document.getElementById("cut_2020").value = settings.getSync('2020.cut') ?? '27.105';
-  document.getElementById("open_2020").value = settings.getSync('2020.open') ?? '27.112.48';
-  setTimer2020();
-} else {
-  document.getElementById("timer_2020").value = '10';
-  document.getElementById("cut_2020").value = '27.105';
-  document.getElementById("open_2020").value = '27.112.48';
-}
-
-// hand main process message http-request
-ipcRenderer.on('http-request-2017', (event, arg) => {
-  connect2017(arg)
-});
-ipcRenderer.on('http-request-2020', (event, arg) => {
-  connect2020(arg)
-});
\ No newline at end of file
+(async () => {
+  if (await settingsHas('api.url')) {
+    document.getElementById("api_url").value = await settingsGet('api.url');
+    document.getElementById("api_key").value = await settingsGet('api.key');
+    document.getElementById("printer_len").value = await settingsGet('printer.len');
+    document.getElementById("reset_btn").classList.remove('d-none');
+    connectionPing();
+    connectWebSocket();
+  } else {
+    document.getElementById("printer_len").value = '48';
+  }
+
+  if (await settingsHas('poll.interval')) {
+    document.getElementById("poll_interval").value = String(await settingsGet('poll.interval'));
+  }
+  applyPollInterval();
+  renderGlobalStatus();
+})();
+
+async function resetSettings() {
+  if (confirm('¿Estás seguro de que quieres borrar toda la configuración?')) {
+    await settingsUnset();
+    alert('Configuración borrada. La aplicación se reiniciará.');
+    ipcRenderer.send('reload-window');
+  }
+}