diff --git a/manifest.json b/manifest.json
index 3b4cceb6..900d106f 100644
--- a/manifest.json
+++ b/manifest.json
@@ -32,18 +32,7 @@
     },
     "default_title": "__MSG_manifest_action_default_title__"
   },
-  "content_scripts": [
-    {
-      "matches": [
-        "<all_urls>"
-      ],
-      "js": [
-        "content.js"
-      ],
-      "all_frames": true,
-      "run_at": "document_start"
-    }
-  ],
+
   "commands": {
     "renew-useragent": {
       "description": "__MSG_manifest_command_renew_useragent__",
@@ -59,6 +48,7 @@
     "tabs",
     "alarms",
     "storage",
+    "scripting",
     "declarativeNetRequest"
   ],
   "$what_the_specified_permissions_are_for": {
diff --git a/src/entrypoints/background/hooks/index.ts b/src/entrypoints/background/hooks/index.ts
index c390f172..ca1bd4ce 100644
--- a/src/entrypoints/background/hooks/index.ts
+++ b/src/entrypoints/background/hooks/index.ts
@@ -1,2 +1,3 @@
 export { setRequestHeaders, unsetRequestHeaders } from './http-requests'
 export { setBridgeData, unsetBridgeData } from './content-script-bridge'
+export { registerContentScripts } from './scripting'
diff --git a/src/entrypoints/background/hooks/scripting.ts b/src/entrypoints/background/hooks/scripting.ts
new file mode 100644
index 00000000..be2b8c92
--- /dev/null
+++ b/src/entrypoints/background/hooks/scripting.ts
@@ -0,0 +1,41 @@
+import RegisteredContentScript = chrome.scripting.RegisteredContentScript
+
+// the common properties for the content scripts
+const common: Omit<RegisteredContentScript, 'id'> = {
+  matches: ['<all_urls>'],
+  allFrames: true,
+  runAt: 'document_start',
+}
+
+// properties for the content script that will be executed in the isolated world (as a content script)
+const content: RegisteredContentScript = { ...common, id: 'content', js: ['content.js'] }
+
+// properties for the content script that will be executed in the main world (as an injected script)
+const inject: RegisteredContentScript = { ...common, id: 'inject', js: [__UNIQUE_INJECT_FILENAME__] }
+
+/** Register the content scripts */
+export async function registerContentScripts() {
+  // first, unregister (probably) previously registered content scripts
+  await chrome.scripting.unregisterContentScripts()
+
+  try {
+    await chrome.scripting.registerContentScripts([
+      { ...content, world: 'ISOLATED' },
+      { ...inject, world: 'MAIN' },
+    ])
+  } catch (err) {
+    if (
+      err instanceof Error &&
+      err.message.toLowerCase().includes('unexpected property') &&
+      err.message.includes('world')
+    ) {
+      // if so, it means that the "world" property is not supported by the current browser (FireFox at this moment)
+      // so we need to register the content scripts without the "world" property
+      //
+      // https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/scripting/RegisteredContentScript#browser_compatibility
+      return await chrome.scripting.registerContentScripts([content, inject])
+    }
+
+    throw err
+  }
+}
diff --git a/src/entrypoints/background/index.ts b/src/entrypoints/background/index.ts
index 81fa495a..0d37ebda 100644
--- a/src/entrypoints/background/index.ts
+++ b/src/entrypoints/background/index.ts
@@ -2,7 +2,7 @@ import { checkPermissions, detectBrowser, watchPermissionsChange } from '~/share
 import { type HandlersMap, listen as listenRuntime } from '~/shared/messaging'
 import { newErrorEvent, newExtensionLoadedEvent } from '~/shared/stats'
 import { isApplicableForDomain, reloadRequestHeadersAndBridge, renewUserAgent, updateRemoteUserAgentList } from './api'
-import { unsetBridgeData, unsetRequestHeaders } from './hooks'
+import { registerContentScripts, unsetBridgeData, unsetRequestHeaders } from './hooks'
 import { registerHotkeys } from './hotkeys'
 import { CurrentUserAgent, RemoteUserAgentList, Settings, StorageArea, UserID } from './persistent'
 import { type Collector as StatsCollector, GaCollector } from './stats'
@@ -17,6 +17,9 @@ let stats: StatsCollector | undefined = undefined
 
 // run the background script
 ;(async () => {
+  // register the content scripts
+  await registerContentScripts()
+
   // at least FireFox does not allow the extension to work with all URLs by default, and the user must grant the
   // necessary permissions. in addition, the user can revoke the permissions at any time, so we need to monitor the
   // changes in the permissions and open the onboarding page if the necessary permissions are missing
diff --git a/src/entrypoints/content/content.ts b/src/entrypoints/content/content.ts
index f3d87fd3..0a36be1d 100644
--- a/src/entrypoints/content/content.ts
+++ b/src/entrypoints/content/content.ts
@@ -47,6 +47,7 @@ const isApplicableToDomain = (currentDomain: string, p: ContentScriptPayload): b
 try {
   const key = __UNIQUE_PAYLOAD_KEY_NAME__
 
+  // get the payload from the storage
   chrome.storage.local.get([key], (items) => {
     if (chrome.runtime.lastError) {
       throw new Error(chrome.runtime.lastError.message)
@@ -59,12 +60,31 @@ try {
     const payload = items[key] as ContentScriptPayload
     const currentDomain = window.location.hostname
 
-    console.log('currentDomain', currentDomain, isApplicableToDomain(currentDomain, payload), payload)
-
     if (!isApplicableToDomain(currentDomain, payload)) {
       return // the script is not applicable to the current domain
     }
 
+    // Important Note:
+    //
+    // Chromium-based browsers (like Chrome, Edge, Opera, etc.) support the `world` property in the
+    // `chrome.scripting.registerContentScripts` API. This property allows content scripts to run in the "isolated"
+    // world, which is necessary for accessing the payload from the storage using the `chrome.store` API. Additionally,
+    // they can run in the "main" world as an "inject" script, which modifies the user agent.
+    //
+    // However, FireFox does not yet support the `world` property. Therefore, I need to ensure that the "inject" script
+    // code is executed in both environments.
+    //
+    // https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/scripting/RegisteredContentScript
+    //
+    // For Chromium-based browsers, the "inject" script is registered as a content script in the
+    // `registerContentScripts` function, resulting in faster execution without adding a <script> tag to the DOM.
+    // FireFox, on the other hand, still requires the "inject" script to be injected using a <script> tag with a src
+    // attribute.
+    //
+    // In summary, the <script> tag is used to pass the payload to the "inject" script in all browsers. Chromium-based
+    // browsers read the payload directly from the <script> tag properties, while FireFox executes the "inject" script
+    // using the <script> tag in the DOM.
+
     injectAndExecuteScript(payload)
   })
 } catch (err) {
diff --git a/src/entrypoints/content/inject.ts b/src/entrypoints/content/inject.ts
index 1636292f..808728c0 100644
--- a/src/entrypoints/content/inject.ts
+++ b/src/entrypoints/content/inject.ts
@@ -2,36 +2,61 @@
 import type { ContentScriptPayload } from '~/shared/types'
 
 /** Extracts the payload from the script tag. */
-const extractPayload = (): ContentScriptPayload | undefined => {
-  const injectedScript = document.getElementById(__UNIQUE_INJECT_FILENAME__) as HTMLScriptElement | null
-  if (!injectedScript) {
-    return // no script to execute = no fun
-  }
-
-  try {
-    const rawPayload = injectedScript.getAttribute('payload')
-    if (!rawPayload) {
-      return
-    }
+const extractPayload = async (
+  timeout: number = 2000,
+  interval: number = 1
+): Promise<ContentScriptPayload | undefined> => {
+  const startedAt = Date.now()
+
+  return new Promise((resolve: (_: Awaited<ReturnType<typeof extractPayload>>) => void): void => {
+    const t = setInterval(() => {
+      // if the timeout is reached, resolve with `undefined`
+      if (Date.now() - startedAt > timeout) {
+        clearInterval(t)
+
+        return resolve(undefined)
+      }
 
-    try {
-      return JSON.parse(rawPayload)
-    } catch (_) {
-      // do nothing
-    }
-  } finally {
-    injectedScript.remove()
-  }
+      const injectedScript = document.getElementById(__UNIQUE_INJECT_FILENAME__) as HTMLScriptElement | null
+      if (!injectedScript) {
+        // no script tag with the specified ID = the script was removed by the previous run of this function OR
+        // the script was not injected yet by the content script
+        return // try again later
+      }
+
+      try {
+        // read the payload from the script tag attribute
+        const rawPayload = injectedScript.getAttribute('payload')
+        if (!rawPayload) {
+          return // try again later
+        }
+
+        // since script tag was found and the payload is not empty, we can clear the interval immediately
+        clearInterval(t)
+
+        try {
+          // parse and resolve the payload
+          return resolve(JSON.parse(rawPayload))
+        } catch (_) {
+          // do nothing
+        }
+      } finally {
+        injectedScript.remove() // remove the script tag
+      }
+    }, interval)
+  })
 }
 
 /** Run the script */
 try {
-  ;(() => {
-    console.log(`%c👻 RUA: Injected script is running`, 'font-weight:bold')
-
-    const payload = extractPayload()
+  ;(async () => {
+    const payload = await extractPayload()
     if (!payload) {
-      return // no payload = no fun
+      // no payload = no fun
+      //
+      // probably, the script was removed by the content script, registered with the `world: 'MAIN'` property
+      // (Chromium-based browsers only)
+      return
     }
 
     /** @link https://developer.mozilla.org/en-US/docs/Web/API/Navigator */