diff --git a/src/background/background.js b/src/background/background.js
index a30a646..b33f50f 100644
--- a/src/background/background.js
+++ b/src/background/background.js
@@ -1,8 +1,13 @@
 //@license magnet:?xt=urn:btih:1f739d935676111cfff4b4693e3816e664797050&dn=gpl-3.0.txt GPL-v3
 import { Manager } from "lib-iitc-manager";
 import browser from "webextension-polyfill";
+import { IS_SCRIPTING_API, IS_USERSCRIPTS_API } from "@/userscripts/env";
 import { _ } from "@/i18n";
-import { inject_plugin } from "./injector";
+import {
+  inject_gm_api,
+  inject_plugin,
+  is_userscripts_api_available,
+} from "@/userscripts/wrapper";
 import {
   onUpdatedListener,
   onRemovedListener,
@@ -11,6 +16,7 @@ import {
 } from "./intel";
 import "./requests";
 import { strToBase64 } from "@/strToBase64";
+import { isIITCEnabled } from "@/userscripts/utils";
 
 const manager = new Manager({
   storage: browser.storage.local,
@@ -37,17 +43,30 @@ const manager = new Manager({
     } catch {
       // If popup is closed, message goes nowhere and an error occurs. Ignore.
     }
+    if (IS_USERSCRIPTS_API) {
+      isIITCEnabled().then((status) => {
+        if (status) {
+          init_userscripts_api();
+          manager.inject().then();
+        }
+      });
+    }
   },
-  inject_plugin: (plugin) => inject_plugin(plugin).then(),
+  inject_plugin: async (plugin) => {
+    await inject_plugin(plugin);
+  },
+  is_daemon: IS_USERSCRIPTS_API,
 });
 
 manager.run().then();
 
-const { onUpdated, onRemoved } = browser.tabs;
-onUpdated.addListener((tabId, status, tab) =>
-  onUpdatedListener(tabId, status, tab, manager)
-);
-onRemoved.addListener(onRemovedListener);
+if (IS_SCRIPTING_API) {
+  const { onUpdated, onRemoved } = browser.tabs;
+  onUpdated.addListener((tabId, status, tab) =>
+    onUpdatedListener(tabId, status, tab, manager)
+  );
+  onRemoved.addListener(onRemovedListener);
+}
 
 browser.runtime.onMessage.addListener(async (request) => {
   switch (request.type) {
@@ -55,6 +74,9 @@ browser.runtime.onMessage.addListener(async (request) => {
       await onRequestOpenIntel();
       break;
     case "toggleIITC":
+      if (IS_USERSCRIPTS_API) {
+        await manage_user_scripts_status(request.value);
+      }
       await onToggleIITC(request.value);
       break;
     case "xmlHttpRequestHandler":
@@ -148,38 +170,84 @@ async function xmlHttpRequestHandler(data) {
       response: JSON.stringify(response),
     });
 
-    const injectedCode = `
+    const bridge_data = strToBase64(String(detail_stringify));
+    if (IS_USERSCRIPTS_API) {
+      let allTabs = await browser.tabs.query({ status: "complete" });
+
+      allTabs = allTabs.filter(function (tab) {
+        return tab.status === "complete" && tab.url;
+      });
+
+      for (const tab of allTabs) {
+        await browser.tabs.sendMessage(tab.id, {
+          type: "xmlHttpRequestToCS",
+          value: bridge_data,
+        });
+      }
+    } else {
+      const injectedCode = `
       document.dispatchEvent(new CustomEvent('bridgeResponse', {
-        detail: "${strToBase64(String(detail_stringify))}"
+        detail: "${bridge_data}"
       }));
     `;
 
-    try {
-      await browser.tabs.executeScript(data.tab_id, {
-        code: injectedCode,
-      });
-    } catch (error) {
-      console.error(`An error occurred while execute script: ${error.message}`);
+      try {
+        await browser.tabs.executeScript(data.tab_id, {
+          code: injectedCode,
+        });
+      } catch (error) {
+        console.error(
+          `An error occurred while execute script: ${error.message}`
+        );
+      }
     }
   }
 
-  const req = new XMLHttpRequest();
-  req.onload = function () {
-    const response = {
-      readyState: this.readyState,
-      responseHeaders: this.responseHeaders,
-      responseText: this.responseText,
-      status: this.status,
-      statusText: this.statusText,
+  try {
+    const response = await fetch(data.url, {
+      method: data.method,
+      headers: data.headers,
+      body: data.method !== "GET" ? data.data : undefined,
+      credentials: data.user && data.password ? "include" : "same-origin",
+    });
+
+    const text = await response.text();
+
+    // Create a response object similar to the one in XMLHttpRequest
+    const responseObject = {
+      readyState: 4,
+      responseHeaders: "Not directly accessible with fetch",
+      responseText: text,
+      status: response.status,
+      statusText: response.statusText,
     };
-    xmlResponse(data.tab_id, data.onload, response);
-  };
-  req.open(data.method, data.url, true, data.user, data.password);
-  for (let [header_name, header_value] of Object.entries(data.headers)) {
-    req.setRequestHeader(header_name, header_value);
+
+    await xmlResponse(data.tab_id, data.onload, responseObject);
+  } catch (error) {
+    console.error("Fetch error:", error);
   }
+}
+
+const init_userscripts_api = () => {
+  if (!is_userscripts_api_available) return;
+  chrome.userScripts.configureWorld({
+    csp: "script-src 'self' 'unsafe-inline'",
+    messaging: true,
+  });
+  inject_gm_api();
+};
 
-  req.send(data.data);
+async function manage_user_scripts_status(status) {
+  if (status === true) {
+    init_userscripts_api();
+    manager.inject().then();
+  } else {
+    try {
+      await chrome.userScripts.unregister();
+    } catch (e) {
+      console.log(e);
+    }
+  }
 }
 
 self.addEventListener("install", () => {
diff --git a/src/background/injector.js b/src/background/injector.js
index 5eb4e1b..efd71dd 100644
--- a/src/background/injector.js
+++ b/src/background/injector.js
@@ -1,40 +1,20 @@
 //@license magnet:?xt=urn:btih:1f739d935676111cfff4b4693e3816e664797050&dn=gpl-3.0.txt GPL-v3
 
 import browser from "webextension-polyfill";
-import { check_matching } from "lib-iitc-manager";
+import {
+  gm_api_for_plugin,
+  is_userscripts_api_available,
+} from "@/userscripts/wrapper";
+import { getNiaTabsToInject, getPluginMatches } from "@/background/utils";
 
 // TODO
 // https://developer.chrome.com/docs/extensions/reference/api/userScripts#developer_mode_for_extension_users
 
-export async function inject_plugin(plugin) {
-  const tabs = await getTabsToInject();
-
-  const is_ingress_tab = (url) => {
-    return /https:\/\/(intel|missions).ingress.com\/*/.test(url);
-  };
-
-  chrome.userScripts.configureWorld({
-    csp: "script-src 'self' 'unsafe-inline'",
-  });
-
-  try {
-    chrome.userScripts.unregister(["iitc"]);
-  } catch (error) {
-    console.log(error);
-  }
-  chrome.userScripts.register([
-    {
-      id: "iitc",
-      matches: ["https://intel.ingress.com/*"],
-      js: [{ code: plugin.code }],
-    },
-  ]);
+export async function inject_plugin_via_content_scripts(plugin, use_gm_api) {
+  const tabs = await getNiaTabsToInject(plugin);
   for (let tab of Object.values(tabs)) {
-    if (
-      (!is_ingress_tab(tab.url) || !check_matching(plugin, "<all_ingress>")) &&
-      !check_matching(plugin, tab.url)
-    ) {
-      continue;
+    if (use_gm_api) {
+      plugin.code = await gm_api_for_plugin(plugin, tab.id);
     }
 
     try {
@@ -58,11 +38,39 @@ export async function inject_plugin(plugin) {
   }
 }
 
-// Fetch all completly loaded Ingress Intel tabs
-export async function getTabsToInject() {
-  let allTabs = await browser.tabs.query({ status: "complete" });
+export async function inject_plugin_via_userscripts_api(plugin, use_gm_api) {
+  if (!is_userscripts_api_available) return;
+
+  if (use_gm_api) {
+    plugin.code = await gm_api_for_plugin(plugin, 0);
+  }
 
-  return allTabs.filter(function (tab) {
-    return tab.status === "complete" && tab.url;
-  });
+  let scripts = [];
+  try {
+    scripts = await chrome.userScripts.getScripts();
+  } catch (e) {
+    console.log(e);
+    return;
+  }
+  const plugin_obj = [
+    {
+      id: plugin.uid,
+      matches:
+        plugin.uid === "gm_api" ? ["https://*/*"] : getPluginMatches(plugin),
+      js: [{ code: plugin.code }],
+      runAt: plugin.uid === "gm_api" ? "document_start" : "document_end",
+      world: "MAIN",
+    },
+  ];
+
+  const is_exist = scripts.some((script) => script.id === plugin.uid);
+  if (!is_exist) {
+    await chrome.userScripts.register(plugin_obj);
+    return;
+  }
+
+  const exist_script = scripts.find((script) => script.id === plugin.uid);
+  if (exist_script.js[0].code !== plugin_obj[0].js[0].code) {
+    await chrome.userScripts.update(plugin_obj);
+  }
 }
diff --git a/src/background/intel.js b/src/background/intel.js
index 49a6fd9..92a7ef0 100644
--- a/src/background/intel.js
+++ b/src/background/intel.js
@@ -1,6 +1,7 @@
 //@license magnet:?xt=urn:btih:1f739d935676111cfff4b4693e3816e664797050&dn=gpl-3.0.txt GPL-v3
 import browser from "webextension-polyfill";
-import { getTabsToInject } from "./injector";
+import { getTabsToInject } from "@/background/utils";
+import { isIITCEnabled } from "@/userscripts/utils";
 
 let lastIITCTab = null;
 
@@ -53,10 +54,8 @@ export function onRemovedListener(tabId) {
 }
 
 async function initialize(manager) {
-  const storage = await browser.storage.local.get(["IITC_is_enabled"]);
-  const status = storage["IITC_is_enabled"];
-
-  if (status !== false) {
+  const status = await isIITCEnabled();
+  if (status) {
     await manager.inject();
   }
 }
diff --git a/src/background/requests.js b/src/background/requests.js
index d2ccb64..777ce26 100644
--- a/src/background/requests.js
+++ b/src/background/requests.js
@@ -2,6 +2,7 @@
 
 import browser from "webextension-polyfill";
 import { parseMeta, ajaxGet, getUniqId } from "lib-iitc-manager";
+import { isIITCEnabled } from "@/userscripts/utils";
 
 const IS_CHROME = !!global.chrome.app;
 const whitelist = [
@@ -65,10 +66,8 @@ async function bypass(tabId, url) {
  * @return {Promise<void>}
  */
 async function maybeInstallUserJs(tabId, url) {
-  const IITC_is_enabled = await browser.storage.local
-    .get(["IITC_is_enabled"])
-    .then((data) => data.IITC_is_enabled);
-  if (IITC_is_enabled === false) {
+  const status = await isIITCEnabled();
+  if (status === false) {
     await bypass(tabId, url);
     return;
   }
diff --git a/src/background/utils.js b/src/background/utils.js
new file mode 100644
index 0000000..36b6478
--- /dev/null
+++ b/src/background/utils.js
@@ -0,0 +1,38 @@
+//@license magnet:?xt=urn:btih:1f739d935676111cfff4b4693e3816e664797050&dn=gpl-3.0.txt GPL-v3
+
+import browser from "webextension-polyfill";
+import { check_matching } from "lib-iitc-manager";
+
+const is_ingress_tab = (url) => {
+  return /https:\/\/(intel|missions).ingress.com\/*/.test(url);
+};
+
+// Fetch all completly loaded tabs
+export async function getTabsToInject() {
+  let allTabs = await browser.tabs.query({ status: "complete" });
+  return allTabs.filter(function (tab) {
+    return tab.status === "complete" && tab.url;
+  });
+}
+
+// Filter all completly loaded Ingress Intel tabs
+export async function getNiaTabsToInject(plugin) {
+  const tabs = await getTabsToInject();
+  return Object.values(tabs).filter(
+    (tab) =>
+      (is_ingress_tab(tab.url) && check_matching(plugin, "<all_ingress>")) ||
+      check_matching(plugin, tab.url)
+  );
+}
+
+export function getPluginMatches(plugin) {
+  let matches = [];
+  if (check_matching(plugin, "<all_ingress>")) {
+    matches.push("https://intel.ingress.com/*");
+    matches.push("https://missions.ingress.com/*");
+  }
+  if (plugin.match) {
+    matches = matches.concat(plugin.match);
+  }
+  return matches;
+}
diff --git a/src/content-scripts/bridge.js b/src/content-scripts/bridge.js
index 8d2e5dc..3fd85c7 100644
--- a/src/content-scripts/bridge.js
+++ b/src/content-scripts/bridge.js
@@ -1,6 +1,7 @@
 //@license magnet:?xt=urn:btih:1f739d935676111cfff4b4693e3816e664797050&dn=gpl-3.0.txt GPL-v3
 
 import browser from "webextension-polyfill";
+import { IS_USERSCRIPTS_API } from "@/userscripts/env";
 import { inject } from "@/content-scripts/utils";
 import { strToBase64 } from "@/strToBase64";
 
@@ -34,6 +35,14 @@ const xmlResponseBridge = async (data) => {
     .then();
 };
 
+browser.runtime.onMessage.addListener(async (request) => {
+  switch (request.type) {
+    case "xmlHttpRequestToCS":
+      bridgeResponse(request.value);
+      break;
+  }
+});
+
 // Sends the entire plugins scoped storage to the page context
 const getStorageBridge = async (req) => {
   const all_storage = await browser.storage.local.get(null);
@@ -48,12 +57,8 @@ const getStorageBridge = async (req) => {
     response: JSON.stringify(plugins_storage),
   });
 
-  const injectedCode = `
-    document.dispatchEvent(new CustomEvent('bridgeResponse', {
-      detail: "${strToBase64(String(detail_stringify))}"
-    }));
-  `;
-  inject(injectedCode);
+  const bridge_base64_data = strToBase64(String(detail_stringify));
+  bridgeResponse(bridge_base64_data);
 };
 
 // Saves the value in the persistent storage in order to synchronize the data with the storage in the page context
@@ -67,3 +72,20 @@ const setValueBridge = async (req) => {
 const delValueBridge = async (req) => {
   await browser.storage.local.remove(req.key);
 };
+
+const bridgeResponse = (bridge_base64_data) => {
+  if (IS_USERSCRIPTS_API) {
+    dispatchEvent(
+      new CustomEvent("bridgeResponse", {
+        detail: bridge_base64_data,
+      })
+    );
+  } else {
+    const injectedCode = `
+    document.dispatchEvent(new CustomEvent('bridgeResponse', {
+      detail: "${bridge_base64_data}"
+    }));
+  `;
+    inject(injectedCode);
+  }
+};
diff --git a/src/content-scripts/loader.js b/src/content-scripts/loader.js
index 67c75f4..bb7b63a 100644
--- a/src/content-scripts/loader.js
+++ b/src/content-scripts/loader.js
@@ -1,29 +1,21 @@
 //@license magnet:?xt=urn:btih:1f739d935676111cfff4b4693e3816e664797050&dn=gpl-3.0.txt GPL-v3
 
-import browser from "webextension-polyfill";
-import { GM } from "./gm-api";
-import { inject, IITCButtonInitJS } from "./utils";
+import { IITCButtonInitJS } from "./utils";
 import { bridgeAction } from "@/content-scripts/bridge";
+import { inject_gm_api } from "@/userscripts/wrapper";
+import { IS_USERSCRIPTS_API } from "@/userscripts/env";
+import { isIITCEnabled } from "@/userscripts/utils";
 
 function preparePage() {
-  document.addEventListener("DOMContentLoaded", function () {
-    if (window.location.hostname === "intel.ingress.com") {
-      window.onload = function () {};
-      document.body.onload = function () {};
-    }
-  });
-
-  inject(
-    `((${GM.toString()}))()\n//# sourceURL=${browser.runtime.getURL(
-      "js/GM_api.js"
-    )}`
-  );
   document.addEventListener("bridgeRequest", bridgeAction);
+  if (IS_USERSCRIPTS_API) return;
+
+  inject_gm_api();
   document.addEventListener("IITCButtonInitJS", IITCButtonInitJS);
 }
 
-browser.storage.local.get(["IITC_is_enabled"]).then((data) => {
-  if (data["IITC_is_enabled"] !== false) {
+isIITCEnabled().then((status) => {
+  if (status) {
     preparePage();
   }
 });
diff --git a/src/content-scripts/utils.js b/src/content-scripts/utils.js
index e04023a..ec2729f 100644
--- a/src/content-scripts/utils.js
+++ b/src/content-scripts/utils.js
@@ -1,61 +1,31 @@
 //@license magnet:?xt=urn:btih:1f739d935676111cfff4b4693e3816e664797050&dn=gpl-3.0.txt GPL-v3
 
-import browser from "webextension-polyfill";
 import { getUID } from "lib-iitc-manager";
-import { strToBase64 } from "@/strToBase64";
+import { gm_api_for_plugin } from "@/userscripts/wrapper";
 
 const LOADED_PLUGINS = [];
 
 export function inject(code) {
-  // const script = document.createElement("script");
-  // script.appendChild(document.createTextNode(code));
-  // (document.body || document.head || document.documentElement).appendChild(
-  //   script
-  // );
-  // script.parentElement.removeChild(script);
-  console.log(code[0]);
-}
-
-function getPluginHash(uid) {
-  return "VMin" + strToBase64(uid);
+  const script = document.createElement("script");
+  script.appendChild(document.createTextNode(code));
+  (document.body || document.head || document.documentElement).appendChild(
+    script
+  );
+  script.parentElement.removeChild(script);
 }
 
 export async function IITCButtonInitJS(e) {
   const tab_id = e.detail.tab_id;
   const plugin = e.detail.plugin;
 
-  const meta = { ...plugin };
-  delete meta.code;
-
   const uid = plugin.uid ? plugin.uid : getUID(plugin);
-  let data_key = getPluginHash(uid);
   if (LOADED_PLUGINS.includes(uid)) {
     console.debug(`Plugin ${uid} is already loaded. Skip`);
   } else {
     LOADED_PLUGINS.push(uid);
     console.debug(`Plugin ${uid} loaded`);
 
-    const name = encodeURIComponent(plugin.name);
-    const injectedCode = [
-      "((GM)=>{",
-      // an implementation of GM API v3 based on GM API v4
-      "const GM_info = GM.info; const unsafeWindow = window;",
-      "const exportFunction = GM.exportFunction; const createObjectIn = GM.createObjectIn; const cloneInto = GM.cloneInto;",
-      "const GM_getValue = (key, value) => GM._getValueSync(key, value);",
-      "const GM_setValue = (key, value) => GM._setValueSync(key, value);",
-      "const GM_xmlhttpRequest = (details) => GM.xmlHttpRequest(details);",
-
-      plugin.code,
-      // adding a new line in case the code ends with a line comment
-      plugin.code.endsWith("\n") ? "" : "\n",
-      `})(GM("${data_key}", ${tab_id}, ${JSON.stringify(meta)}))`,
-
-      // Firefox lists .user.js among our own content scripts so a space at start will group them
-      `\n//# sourceURL=${browser.runtime.getURL(
-        "plugins/%20" + name + ".user.js"
-      )}`,
-    ].join("");
-
-    inject(injectedCode);
+    const code = gm_api_for_plugin(plugin, tab_id);
+    inject(code);
   }
 }
diff --git a/src/manifest.json b/src/manifest.json
index 9400ae0..14d866b 100644
--- a/src/manifest.json
+++ b/src/manifest.json
@@ -1,7 +1,7 @@
 {
   "name": "IITC Button",
   "description": "__MSG_extDescription__",
-  "minimum_chrome_version": "120",
+  "minimum_chrome_version": "61",
   "browser_specific_settings": {
     "gecko": {
       "id": "iitc@modos189.ru",
@@ -14,31 +14,11 @@
   "permissions": [
     "tabs",
     "storage",
-    "scripting",
-    "webRequest",
-    "userScripts",
     "unlimitedStorage"
   ],
-  "host_permissions": [
-    "https://intel.ingress.com/*"
-  ],
-  "optional_host_permissions":[
-    "https://*/*",
-    "http://*/*"
-  ],
-
   "default_locale": "en",
-  "background": {
-    "service_worker": "js/background.js"
-  },
-  "content_scripts": [
-    {
-      "matches" : ["<all_urls>"],
-      "run_at": "document_start",
-      "js": ["js/content-script.js"]
-    }
-  ],
-  "action": {
+  "background": {},
+  "browser_action": {
     "default_popup": "popup.html",
     "default_title": "__MSG_titleDefault__",
     "default_icon": {
@@ -49,9 +29,5 @@
   "icons": {
     "48": "assets/icons/48/icon.png",
     "128": "assets/icons/128/icon.png"
-  },
-  "content_security_policy": {
-    "extension_pages": "default-src 'self'; style-src 'self' 'unsafe-inline'; script-src 'self'; connect-src 'self' ws://localhost:9090 http://localhost:8000 https://github.com https://iitc.app; img-src 'self' https://iitc.app"
-  },
-  "manifest_version": 3
+  }
 }
diff --git a/src/userscripts/env.js b/src/userscripts/env.js
new file mode 100644
index 0000000..473347a
--- /dev/null
+++ b/src/userscripts/env.js
@@ -0,0 +1,9 @@
+//@license magnet:?xt=urn:btih:1f739d935676111cfff4b4693e3816e664797050&dn=gpl-3.0.txt GPL-v3
+
+import browser from "webextension-polyfill";
+
+export const IS_CHROME = !!browser.runtime.OnInstalledReason.CHROME_UPDATE;
+export const MANIFEST = browser.runtime.getManifest();
+
+export const IS_USERSCRIPTS_API = IS_CHROME && MANIFEST.manifest_version === 3;
+export const IS_SCRIPTING_API = !IS_USERSCRIPTS_API;
diff --git a/src/content-scripts/gm-api.js b/src/userscripts/gm-api.js
similarity index 95%
rename from src/content-scripts/gm-api.js
rename to src/userscripts/gm-api.js
index 8b09d43..ab03f57 100644
--- a/src/content-scripts/gm-api.js
+++ b/src/userscripts/gm-api.js
@@ -1,5 +1,12 @@
 //@license magnet:?xt=urn:btih:1f739d935676111cfff4b4693e3816e664797050&dn=gpl-3.0.txt GPL-v3
 export const GM = function () {
+  document.addEventListener("DOMContentLoaded", function () {
+    if (window.location.hostname === "intel.ingress.com") {
+      window.onload = function () {};
+      document.body.onload = function () {};
+    }
+  });
+
   const cache = {};
   const defineProperty = Object.defineProperty;
 
@@ -178,7 +185,7 @@ export const GM = function () {
       cloneInto: makeFunc((obj) => obj),
     };
   };
-  document.addEventListener("bridgeResponse", function (e) {
+  addEventListener("bridgeResponse", function (e) {
     const detail = JSON.parse(base64ToStr(e.detail));
     const uuid = detail.task_uuid;
 
diff --git a/src/userscripts/utils.js b/src/userscripts/utils.js
new file mode 100644
index 0000000..e88bcfe
--- /dev/null
+++ b/src/userscripts/utils.js
@@ -0,0 +1,10 @@
+//@license magnet:?xt=urn:btih:1f739d935676111cfff4b4693e3816e664797050&dn=gpl-3.0.txt GPL-v3
+
+import browser from "webextension-polyfill";
+
+export async function isIITCEnabled() {
+  const status = await browser.storage.local
+    .get(["IITC_is_enabled"])
+    .then((data) => data["IITC_is_enabled"]);
+  return status !== false;
+}
diff --git a/src/userscripts/wrapper.js b/src/userscripts/wrapper.js
new file mode 100644
index 0000000..483ba99
--- /dev/null
+++ b/src/userscripts/wrapper.js
@@ -0,0 +1,87 @@
+//@license magnet:?xt=urn:btih:1f739d935676111cfff4b4693e3816e664797050&dn=gpl-3.0.txt GPL-v3
+
+import browser from "webextension-polyfill";
+import { IS_USERSCRIPTS_API } from "@/userscripts/env";
+import {
+  inject_plugin_via_content_scripts,
+  inject_plugin_via_userscripts_api,
+} from "@/background/injector";
+import { strToBase64 } from "@/strToBase64";
+import { getUID } from "lib-iitc-manager";
+import { inject } from "@/content-scripts/utils";
+import { GM } from "@/userscripts/gm-api";
+import { isIITCEnabled } from "@/userscripts/utils";
+
+function getPluginHash(uid) {
+  return "VMin" + strToBase64(uid);
+}
+
+export async function inject_plugin(plugin, use_gm_api) {
+  if (use_gm_api === undefined) use_gm_api = true;
+
+  const iitc_status = await isIITCEnabled();
+  if (iitc_status === false) return;
+
+  if (IS_USERSCRIPTS_API) {
+    console.log("INJECT LIKE IS CHROME MV3");
+    await inject_plugin_via_userscripts_api(plugin, use_gm_api);
+  } else {
+    console.log("INJECT LIKE OTHER BROWSER");
+    await inject_plugin_via_content_scripts(plugin, use_gm_api);
+  }
+}
+
+export function inject_gm_api() {
+  const plugin = {
+    uid: "gm_api",
+    code: `((${GM.toString()}))()\n//# sourceURL=${browser.runtime.getURL(
+      "js/GM_api.js"
+    )}`,
+  };
+
+  if (IS_USERSCRIPTS_API) {
+    inject_plugin_via_userscripts_api(plugin, false).then();
+  } else {
+    inject(plugin.code);
+  }
+}
+
+export async function gm_api_for_plugin(plugin, tab_id) {
+  const uid = plugin.uid ? plugin.uid : getUID(plugin);
+  let data_key = getPluginHash(uid);
+  const name = encodeURIComponent(plugin.name);
+
+  const meta = { ...plugin };
+  delete meta.code;
+
+  return [
+    "((GM)=>{",
+    // an implementation of GM API v3 based on GM API v4
+    "const GM_info = GM.info; const unsafeWindow = window;",
+    "const exportFunction = GM.exportFunction; const createObjectIn = GM.createObjectIn; const cloneInto = GM.cloneInto;",
+    "const GM_getValue = (key, value) => GM._getValueSync(key, value);",
+    "const GM_setValue = (key, value) => GM._setValueSync(key, value);",
+    "const GM_xmlhttpRequest = (details) => GM.xmlHttpRequest(details);",
+
+    plugin.code,
+    // adding a new line in case the code ends with a line comment
+    plugin.code.endsWith("\n") ? "" : "\n",
+    `})(GM("${data_key}", ${tab_id}, ${JSON.stringify(meta)}))`,
+
+    // Firefox lists .user.js among our own content scripts so a space at start will group them
+    `\n//# sourceURL=${browser.runtime.getURL(
+      "plugins/%20" + name + ".user.js"
+    )}`,
+  ].join("");
+}
+
+export function is_userscripts_api_available() {
+  try {
+    // Property access which throws if developer mode is not enabled.
+    chrome.userScripts;
+    return true;
+  } catch {
+    // Not available.
+    return false;
+  }
+}
diff --git a/vue.config.js b/vue.config.js
index c6dd67e..e708a61 100644
--- a/vue.config.js
+++ b/vue.config.js
@@ -1,3 +1,68 @@
+const manifest_transformer = (manifest) => {
+  const browser = process.env.BROWSER;
+  const manifest_version = process.env.MANIFEST_VERSION;
+
+  if (manifest_version === "2") {
+    manifest_v2_transformer(manifest, browser);
+  } else if (manifest_version === "3") {
+    manifest_v3_transformer(manifest, browser);
+  }
+  manifest.manifest_version = parseInt(manifest_version);
+};
+
+const manifest_v2_transformer = (manifest, browser) => {
+  manifest.content_scripts = [
+    {
+      matches: ["<all_urls>"],
+      run_at: "document_start",
+      js: ["js/content-script.js"],
+    },
+  ];
+  manifest.permissions.push("<all_urls>");
+  manifest.permissions.push("scripting");
+  manifest.permissions.push("webRequest");
+  manifest.permissions.push("webRequestBlocking");
+  manifest.background.page = "background.html";
+
+  if (browser === "safari-ios") {
+    manifest.background.persistent = false;
+  }
+};
+
+const manifest_v3_transformer = (manifest, browser) => {
+  manifest.host_permissions = [
+    "https://intel.ingress.com/*",
+    "https://missions.ingress.com/*",
+    "https://v.enl.one/",
+  ];
+  manifest.optional_host_permissions = ["https://*/*", "http://*/*"];
+  manifest.content_security_policy = {
+    extension_pages:
+      "default-src 'self'; style-src 'self' 'unsafe-inline'; script-src 'self'; connect-src 'self' ws://localhost:9090 http://localhost:8000 https://*; img-src 'self' https://iitc.app",
+  };
+  manifest.content_scripts = [
+    {
+      matches: ["<all_urls>"],
+      run_at: "document_start",
+      js: ["js/content-script.js"],
+    },
+  ];
+
+  manifest.action = manifest.browser_action;
+  delete manifest.browser_action;
+
+  if (browser === "chrome") {
+    manifest.minimum_chrome_version = "120";
+    manifest.permissions.push("userScripts");
+    manifest.background.service_worker = "js/background.js";
+  } else {
+    manifest.permissions.push("scripting");
+    manifest.permissions.push("webRequest");
+    manifest.permissions.push("webRequestBlocking");
+    manifest.background.page = "background.html";
+  }
+};
+
 module.exports = {
   filenameHashing: false,
   productionSourceMap: false,
@@ -35,13 +100,7 @@ module.exports = {
         },
       },
       manifestTransformer: (manifest) => {
-        if (process.env.BROWSER === "safari-ios") {
-          manifest.background.persistent = false;
-        }
-        if (process.env.BROWSER === "firefox") {
-          manifest.permissions.append("webRequestBlocking");
-          manifest.background.page = "background.html";
-        }
+        manifest_transformer(manifest);
         return manifest;
       },
     },