diff --git a/ManifestBuilder.js b/ManifestBuilder.js
index b3fada3..b923402 100644
--- a/ManifestBuilder.js
+++ b/ManifestBuilder.js
@@ -3,21 +3,28 @@
 const integrations = require('./integrationList.json');
 
 module.exports = {
-    build: function (isDebug = false) {
+    build: function (serverProtocol, serverDomain, browser, isDebug = false) {
         if (isDebug) {
             integrations.push({
-                "matches": ["*://localhost:*/*"],
+                "matches": ["*://localhost/*/*"],
                 "script": ["for-development-only.js"]
             })
         }
 
+        if (browser === "firefox") {
+            integrations.push({
+                "matches": [serverProtocol + '://' + serverDomain + '/*'],
+                "script": ["timecamp-firefox-helper.js"]
+            })
+        }
+
         let contentScripts = [];
         for (const integration of integrations) {
             if (!isDebug && integration.isActiveInProd !== true) {
                 continue;
             }
 
-            contentScripts.push({
+            let item = {
                 'matches': [
                     ...this.defaults.matches,
                     ...integration.matches
@@ -31,7 +38,13 @@ module.exports = {
                     ...this.defaults.js,
                     'scripts-2.0/third_party/' + integration.script,
                 ],
-            });
+            };
+
+            if (item.exclude_matches.length === 0) {
+                delete item.exclude_matches;
+            }
+
+            contentScripts.push(item);
         }
 
         return contentScripts;
diff --git a/README.md b/README.md
index 2be0b3c..b83a5da 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,10 @@ TimeCamp Browser Plugin Extension
   npm install  --legacy-peer-deps
 ```
 
+## Firefox
+To build for Firefox just run: `export BROWSER=firefox`
+To switch back to Chrome run: `unset BROWSER`
+
 ## Build for production
 1. `unset SERVER_DOMAIN` or revert domain changes - just in case if you changed for development
 2. `npm run-script build-prod` - it creates archive `dist/timecamp-browser-extension-2.x.x.zip` and directory `dist/plugin` with same unzipped files
diff --git a/manifest.chrome.json b/manifest.chrome.json
new file mode 100644
index 0000000..a7374cd
--- /dev/null
+++ b/manifest.chrome.json
@@ -0,0 +1,6 @@
+{
+  "background": {
+    "service_worker": "scripts/background.js"
+  },
+  "offline_enabled": false
+}
diff --git a/manifest.firefox.json b/manifest.firefox.json
new file mode 100644
index 0000000..9914c05
--- /dev/null
+++ b/manifest.firefox.json
@@ -0,0 +1,10 @@
+{
+  "background": {
+    "scripts": ["scripts/background.js"]
+  },
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "dev@timecamp.com"
+    }
+  }
+}
\ No newline at end of file
diff --git a/manifest.json b/manifest.json
index 010a4b3..a950498 100644
--- a/manifest.json
+++ b/manifest.json
@@ -123,15 +123,11 @@
     ],
     "homepage_url": "http://www.timecamp.com/",
     "incognito": "spanning",
-    "offline_enabled": false,
     "permissions": [
         "tabs",
         "storage"
     ],
     "host_permissions": ["https://*.timecamp.com/*"],
-    "background": {
-        "service_worker": "scripts/background.js"
-    },
     "web_accessible_resources": [{
         "resources":[
             "images/*.gif",
@@ -142,4 +138,4 @@
         ],
         "matches": ["<all_urls>"]
       }]
-}
+}
\ No newline at end of file
diff --git a/package.json b/package.json
index c95592b..e5352c9 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "timecamp-chrome-extension",
-  "version": "2.85.2",
+  "version": "2.85.22",
   "description": "TimeCamp Google Chrome Time Tracking Extension",
   "main": "index.js",
   "scripts": {
@@ -11,7 +11,7 @@
     "build-dev": "webpack-cli --mode development && npm run merge-background-files",
     "build-prod-unsafe": "webpack-cli --mode production && npm run merge-background-files && npm run zip",
     "merge-background-files": "cat 'dist/plugin/scripts-2.0/background-2.0.js' >> 'dist/plugin/scripts/background.js'",
-    "zip": "bash -c \"pushd dist/plugin && zip -rq ../timecamp-browser-extension-`node -p \"require('./package.json').version\"`.zip * && popd\""
+    "zip": "bash -c \" pushd dist/plugin && zip -rq ../timecamp-browser-extension-`node -p \"require('./package.json').version\"`-`if [ $BROWSER == \"firefox\" ]; then echo \"firefox\"; else echo \"chromium\"; fi`.zip * && popd\""
   },
   "babel": {
     "presets": [
diff --git a/scripts-2.0/ApiService.js b/scripts-2.0/ApiService.js
index 5957dfc..30889c2 100644
--- a/scripts-2.0/ApiService.js
+++ b/scripts-2.0/ApiService.js
@@ -863,9 +863,9 @@ export default class ApiService {
 
     removeStoredToken() {
         return new Promise((resolve, reject) => {
-            chrome.storage.sync.clear();
-            chrome.storage.sync.set({ 'removed': true }, function () {
-                if (chrome.runtime.lastError) {
+            browser.storage.sync.clear();
+            browser.storage.sync.set({ 'removed': true }).then(() => {
+                if (browser.runtime.lastError) {
                     reject();
                 } else {
                     resolve(true);
@@ -876,10 +876,10 @@ export default class ApiService {
 
     storeToken(token) {
         return new Promise((resolve, reject) => {
-            chrome.storage.sync.set({ 'token': token, 'removed': false }, function () {
+            browser.storage.sync.set({ 'token': token, 'removed': false }).then(() => {
                 resolve();
-                if (chrome.runtime.lastError) {
-                    logger.error(chrome.runtime.lastError.message);
+                if (browser.runtime.lastError) {
+                    logger.error(browser.runtime.lastError.message);
                 }
             });
         });
@@ -887,10 +887,10 @@ export default class ApiService {
 
     storeNextToken(token) {
         return new Promise((resolve, reject) => {
-            chrome.storage.sync.set({ 'next_token': token, 'removed': false }, function () {
+            browser.storage.sync.set({ 'next_token': token, 'removed': false }).then(() => {
                 resolve();
-                if (chrome.runtime.lastError) {
-                    logger.error(chrome.runtime.lastError.message);
+                if (browser.runtime.lastError) {
+                    logger.error(browser.runtime.lastError.message);
                 }
             });
         });
@@ -898,9 +898,9 @@ export default class ApiService {
 
     getStoredToken() {
         return new Promise((resolve, reject) => {
-            chrome.storage.sync.get('token', function (items) {
+            browser.storage.sync.get('token').then((items) => {
                 var token = items['token'];
-                if (token && !chrome.runtime.lastError) {
+                if (token && !browser.runtime.lastError) {
                     resolve(token);
                 } else {
                     reject();
@@ -911,9 +911,9 @@ export default class ApiService {
 
     getStoredNextToken() {
         return new Promise((resolve, reject) => {
-            chrome.storage.sync.get('next_token', function (items) {
+            browser.storage.sync.get('next_token').then((items) => {
                 var token = items['next_token'];
-                if (token && !chrome.runtime.lastError) {
+                if (token && !browser.runtime.lastError) {
                     resolve(token);
                 } else {
                     reject();
@@ -924,8 +924,8 @@ export default class ApiService {
 
     getLoggedOutFlag() {
         return new Promise((resolve, reject) => {
-            chrome.storage.sync.get('removed', function (items) {
-                if (chrome.runtime.lastError) {
+            browser.storage.sync.get('removed').then((items) => {
+                if (browser.runtime.lastError) {
                     reject();
                     return;
                 }
diff --git a/scripts-2.0/StorageManager.js b/scripts-2.0/StorageManager.js
index a486700..304035f 100644
--- a/scripts-2.0/StorageManager.js
+++ b/scripts-2.0/StorageManager.js
@@ -19,11 +19,11 @@ export default class StorageManager {
             browser.storage.sync.get(key).then((items) => {
                 let data = items[key];
 
-                if (browser.runtime.lastError === undefined) {
+                if (!browser.runtime.lastError) {
                     resolve(data);
                 } else {
-                    logger.error(browser.runtime.lastError.message);
-                    reject(browser.runtime.lastError.message);
+                    logger.error(browser.runtime.lastError?.error);
+                    reject(browser.runtime.lastError?.error);
                 }
             }).catch((e) => {
                 reject(e);
@@ -34,11 +34,11 @@ export default class StorageManager {
     set(key, data) {
         return new Promise((resolve, reject) => {
             browser.storage.sync.set({[key]: data}).then(() => {
-                if (browser.runtime.lastError === undefined) {
+                if (!browser.runtime.lastError) {
                     resolve();
                 } else {
-                    logger.error(browser.runtime.lastError.message);
-                    reject(browser.runtime.lastError.message);
+                    logger.error(browser.runtime.lastError?.error);
+                    reject(browser.runtime.lastError?.error);
                 }
             }).catch((e) => {
                 reject(e);
diff --git a/scripts-2.0/background.js b/scripts-2.0/background.js
index 27cb2df..109df6d 100644
--- a/scripts-2.0/background.js
+++ b/scripts-2.0/background.js
@@ -369,6 +369,9 @@ const TcButton = {
                             reject(error);
                         });
                         break;
+                    case 'tokenUpdate':
+                        TcButton.login(request.token);
+                        break;
                 }
             } catch (e) {
                 logger.error(e);
@@ -377,13 +380,13 @@ const TcButton = {
         });
     },
 
+    //used only by chrome
     newMessageExternal: (request, sender, sendResponse) => {
         return new Promise((resolve, reject) => {
             try {
                 switch (request.type) {
                     case 'tokenUpdate':
-                        apiService.storeToken(request.token);
-                        TcButton.doAfterLogin();
+                        TcButton.login(request.token);
                         break;
                 }
             } catch (e) {
@@ -457,6 +460,11 @@ const TcButton = {
         });
     },
 
+    login: (token) => {
+        apiService.storeToken(token);
+        TcButton.doAfterLogin();
+    },
+
     doAfterLogin: () => {
         return new Promise((resolve, reject) => {
             TcButton.isUserLogged = true;
@@ -723,6 +731,8 @@ browser.runtime.onMessage.addListener(function (request, sender, sendResponse) {
     //tracking
     return analyticsService.logEvent(request, sender, sendResponse)
 });
+
+//used only by chrome
 browser.runtime.onMessageExternal.addListener(TcButton.newMessageExternal);
 setInterval(() => {
     const promise = TcButton.updateCurrentEntry();
diff --git a/scripts-2.0/third_party/timecamp-firefox-helper.js b/scripts-2.0/third_party/timecamp-firefox-helper.js
new file mode 100644
index 0000000..57463b6
--- /dev/null
+++ b/scripts-2.0/third_party/timecamp-firefox-helper.js
@@ -0,0 +1,8 @@
+'use strict';
+
+//firefox helper for pass data from website to background script
+window.addEventListener("message", (event) => {
+    if (event.data.type === 'tokenUpdate') {
+        browser.runtime.sendMessage(event.data);
+    }
+}, false);
\ No newline at end of file
diff --git a/webpack.config.js b/webpack.config.js
index a740d6e..d9f5b39 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -12,7 +12,7 @@ const ENV = {
   SERVER_PROTOCOL: process.env.SERVER_PROTOCOL || 'https',
   SERVER_DOMAIN: process.env.SERVER_DOMAIN || 'app.timecamp.com',
   NEXT_SERVER_DOMAIN: "v4.api.timecamp.com",
-  MARKETING_PAGE_DOMAIN: 'www.timecamp.com', 
+  MARKETING_PAGE_DOMAIN: 'www.timecamp.com',
   GOOGLE_ANALYTICS_ID: 'UA-4525089-16'
 };
 
@@ -214,7 +214,7 @@ function transformOldConfig() {
 }
 
 function transformManifest(isDebug = false) {
-  return function (content) {
+  return async function (content) {
     const manifest = JSON.parse(content.toString());
     manifest.homepage_url = ENV.SERVER_PROTOCOL + '://' + ENV.SERVER_DOMAIN + '/';
     manifest.host_permissions = [
@@ -224,16 +224,24 @@ function transformManifest(isDebug = false) {
 
     manifest.externally_connectable.matches = [
       ...manifest.externally_connectable.matches,
-      ENV.SERVER_PROTOCOL + '://' + ENV.SERVER_DOMAIN + '/*'
+      ENV.SERVER_PROTOCOL + '://' + ENV.SERVER_DOMAIN + '/*',
     ];
 
+    const browser = process.env.BROWSER === "firefox" ? "firefox" : "chrome";
+
     manifest.content_scripts = [
       ...manifest.content_scripts,
-      ...ManifestBuilder.build(isDebug)
+      ...ManifestBuilder.build(ENV.SERVER_PROTOCOL, ENV.SERVER_DOMAIN, browser, isDebug)
     ];
 
     manifest.version = pkg.version;
 
-    return Buffer.from(JSON.stringify(manifest, undefined, 2));
+    const browserSpecificManifestPath = `manifest.${browser}.json`;
+
+    const file = await fs.promises.readFile(browserSpecificManifestPath);
+    const fileContent = JSON.parse(file.toString());
+    const manifestResult = Object.assign(manifest, fileContent);
+
+    return Buffer.from(JSON.stringify(manifestResult, undefined, 2));
   };
 }