To enable Smart Window in Firefox, open Menu > Settings > AI Controls, find Smart Window, and set it to Available or Enabled. You can then open the Firefox menu and select New Smart Window. To disable it completely, return to AI Controls and set Smart Window to Blocked.
If Smart Window does not appear in Settings, update Firefox and confirm that you use the desktop browser with an eligible language, region and Mozilla account. Advanced users can also check the browser.smartwindow.enabled preference in about:config, although changing this flag does not guarantee access when Mozilla has not enabled the feature for the account or region.
Update, July 2026: Mozilla is gradually making Smart Window available to stable Firefox users. The rollout started with Firefox 150 in the United States and Canada and continues across later releases, including the Firefox 152 series. Availability still varies between users.
| Setting | Result |
|---|---|
| Available | Smart Window appears in Firefox and can be opened when needed. |
| Enabled | You have opted in and completed Smart Window setup. |
| Blocked | Firefox removes Smart Window access points and stops promoting the feature. |
| Block AI enhancements | Blocks Smart Window and other current or future generative AI features by default. |
What is Smart Window or AI Window Mode in Mozilla Firefox?
Smart Window is an optional Firefox desktop window type with a built-in AI assistant. Mozilla previously referred to the project as AI Window before adopting the Smart Window name.
A Smart Window works alongside normal Firefox windows rather than replacing them. You can keep Classic, Smart and Private windows open at the same time and switch a regular window to Smart Window without closing its tabs.
The assistant can use the pages and tabs you choose to reference to perform tasks such as:
- Summarising the current webpage
- Comparing information across open tabs
- Answering questions about a page
- Generating recommendations
- Helping plan tasks with information from selected tabs
- Finding information from browsing history when requested
Smart Window also includes a chat box on the New Tab page and an assistant sidebar that you can open while viewing a website.
Smart Window and the Firefox AI chatbot are different
The standard AI chatbot available in the Firefox sidebar connects to providers such as ChatGPT, Gemini or Copilot. It does not receive access to your open tabs or browsing history from Firefox.
The Smart Window assistant has deeper browser integration. It can work with referenced tabs, the current page and browsing history that you explicitly ask it to use. Optional Memories can also personalise responses based on your activity.
Smart Window requirements
Smart Window currently requires:
- Firefox for desktop
- A supported Firefox release
- A Mozilla account
- An eligible language and region
- Access through Mozilla’s gradual rollout
Mozilla currently documents availability for en-US and en-CA users in the United States and Canada. Changing the Firefox language or an advanced preference does not necessarily bypass account or server-side eligibility checks.
How to Enable and Test Smart Window Feature in Mozilla Firefox
Method 1: Enable Smart Window from Firefox Settings
Use the AI Controls page first because it is Mozilla’s supported method and does not require changing hidden browser preferences.
- Update Firefox to the latest available version.
- Click the three-line Menu button in the upper-right corner.
- Select Settings.
- Choose AI Controls in the left sidebar.
- Find Smart Window.
- Select Available or Enabled, depending on the options shown.
- Complete the Smart Window onboarding process when prompted.
You can open the AI Controls page directly by entering the following address:
about:preferences#aiIf the Smart Window option is missing or unavailable, Firefox has probably not enabled it for your profile, account, language or region yet.
Open a new Smart Window
After completing setup:
- Open the Firefox menu.
- Select New Smart Window.
Firefox opens a separate Smart Window while leaving existing Classic and Private windows unchanged.
Switch a Classic Window to Smart Window
You can convert the current Firefox window without reopening its tabs:
- Open the Firefox menu from the current window.
- Select Smart Window.
The same tabs remain open while Firefox changes the window interface and adds the Smart Window assistant.
Method 2: Enable Smart Window through about:config
The following advanced preference can expose Smart Window on some Firefox installations where the interface has not appeared automatically:
- Enter
about:configin the address bar. - Select Accept the Risk and Continue.
- Search for:
browser.smartwindow.enabled- Double-click the preference to change its value to true.
- Restart Firefox if the Smart Window button or menu option does not appear immediately.
- Sign in to your Mozilla account and complete setup.
The preference controls whether Firefox exposes Smart Window support in the browser interface. It does not guarantee that the service will work when your account, language or region is outside Mozilla’s current rollout.
Note: Preferences on the
about:configpage are intended for advanced testing. Mozilla can rename, remove or change their behaviour in later Firefox releases.
Choose an AI model during setup
Firefox asks you to choose the model that powers the built-in assistant when you open Smart Window for the first time.
| Firefox label | Model | Provider | Intended use |
|---|---|---|---|
| Fast | Gemini 2.5 Flash Lite | Faster responses and shorter answers | |
| Flexible | Qwen3 235B A22B Instruct | Alibaba | General-purpose assistance |
| Personalized | GPT-OSS 120B | OpenAI | More frequent use of optional personalisation |
Mozilla can change the available models as the Smart Window beta develops. You can switch models later without repeating the full setup process.
How to Change or Customize Smart Window Settings in Mozilla Firefox
Firefox provides a dedicated Smart Window settings page for its assistant, model and startup behaviour.
- Open the Firefox menu.
- Select Settings.
- Open AI Controls.
- Select Smart Window settings.
You can also enter about:preferences#ai in the address bar and open the Smart Window section.
Stop the assistant sidebar from opening automatically
The assistant can open automatically when you create a tab in Smart Window. To keep it closed by default:
- Open Settings > AI Controls.
- Select Smart Window settings.
- Find the default settings section.
- Turn off Open assistant automatically.
The assistant remains available through the Ask button whenever you need it.
Change the default Smart Window AI model
- Open Settings > AI Controls.
- Select Smart Window settings.
- Open the Assistant model menu.
- Choose Fast, Flexible, Personalized or an available custom model.
This selection applies to future conversations by default.
Change the model for one chat
You can use a different model for the current conversation without changing the default:
- Open a Smart Window.
- Open a new Smart Window tab or click Ask.
- Select the current model name in the chat interface.
- Choose another model.
The change applies only to that chat. New conversations continue using the default model selected in Firefox Settings.
Use Smart Window by default
Firefox 151.0.2 and later can open Smart Window automatically when you start the browser or open a link from another application, provided Smart Window is available and onboarding is complete.
- Open Settings > AI Controls.
- Select Smart Window settings.
- Turn on Use Smart Window by default.
If Firefox cannot open Smart Window, it falls back to a Classic window.
Manage Smart Window Memories
Memories allow the assistant to create optional personalisation from Smart Window chats and browsing patterns. Mozilla says memories and chat history are stored locally on the device.
To review or disable them:
- Open Smart Window settings.
- Find the Memories section.
- View or delete individual memories, or turn the feature off.
Smart Window does not use activity from Private Windows to create memories.
How to Disable or Remove Smart Window Feature in Mozilla Firefox
Switch back to a Classic Window
Use this option when you want to leave Smart Window without blocking the feature:
- Open the Firefox menu inside the Smart Window.
- Select Classic Window.
Your open tabs remain in the window while Firefox returns to its normal interface.
Block Smart Window from Firefox Settings
Blocking the feature removes its buttons, menu entries and promotional prompts:
- Open Firefox Settings.
- Select AI Controls.
- Find Smart Window.
- Set it to Blocked.
You can restore access later by changing the setting back to Available or Enabled.
Disable all Firefox generative AI features
Firefox includes one switch for users who do not want current or future generative AI features:
- Open Settings > AI Controls.
- Turn on Block AI enhancements.
This blocks Smart Window and other covered features, including AI chatbot access, AI tab-group suggestions and AI-generated link-preview key points. Firefox also stops showing prompts for blocked features.
Disable Smart Window through about:config
You can restore the hidden preference when you previously enabled the feature manually:
- Enter
about:configin the Firefox address bar. - Accept the warning.
- Search for
browser.smartwindow.enabled. - Double-click the preference to set it to false.
- Restart Firefox if the interface does not change immediately.
Use the AI Controls setting when it is available because it also manages feature prompts and related access points.
Why Is Smart Window Missing in Firefox?
Smart Window can remain unavailable even after installing Firefox 152.0.4 or a newer version. Check the following conditions:
- You use Firefox desktop rather than Firefox for Android or iPhone.
- Firefox is updated through Menu > Help > About Firefox.
- You signed in with a Mozilla account.
- Your Firefox language is en-US or en-CA.
- Your account and location are included in Mozilla’s gradual rollout.
- Smart Window is not set to Blocked in AI Controls.
- The main Block AI enhancements switch is turned off.
Enabling browser.smartwindow.enabled can reveal the interface on some installations, but it cannot reliably unlock server-controlled access.
Smart Window Privacy: What Firefox Can Access
When you use the built-in assistant, Smart Window can work with:
- The page currently displayed
- Tabs that you explicitly reference
- Page titles, addresses and relevant page content
- Browsing history that you ask it to search
- Optional memories created from eligible activity
Mozilla says Smart Window cannot access Private Window activity, saved passwords, payment information, unread email or arbitrary files stored on the device.
Requests pass through Mozilla’s servers before reaching the selected model provider. Chat conversations and memories remain stored locally, while model providers process prompts to return responses. Review the Smart Window privacy notice before enabling the feature when you regularly browse confidential work, financial or personal information.
FAQs
Is Firefox Smart Window enabled by default?
No. Smart Window is optional and requires the user to opt in and complete setup. Mozilla is releasing it gradually, so it does not appear for every Firefox user.
Which Firefox version includes Smart Window?
Mozilla began gradually making Smart Window available with Firefox 150. Later releases, including Firefox 151 and 152, continue supporting it for eligible desktop users.
Does Firefox 152.0.4 guarantee access to Smart Window?
No. Installing Firefox 152.0.4 provides a supported browser version, but access also depends on Mozilla’s rollout, account, language and region requirements.
Can I enable Smart Window without a Mozilla account?
No. Mozilla currently requires users to sign in with a Mozilla account before completing Smart Window onboarding.
Does Smart Window work on Firefox for Android or iPhone?
No. Mozilla currently documents Smart Window as a Firefox desktop feature.
Can I use Smart Window and normal Firefox windows together?
Yes. Firefox allows Classic, Smart and Private windows to remain open at the same time.
Will switching to Smart Window close my open tabs?
No. When you convert a Classic Window to Smart Window, its existing tabs remain open.
How do I remove the Smart Window assistant sidebar?
Click the Ask button to close it temporarily. To keep it closed on new tabs, open Smart Window settings and disable Open assistant automatically.
Can I change the Smart Window model?
Yes. Open Settings > AI Controls > Smart Window settings to change the default model. You can also select another model inside an individual chat.
What does browser.smartwindow.enabled do?
The preference controls whether Firefox exposes Smart Window functionality in supported builds. Setting it to true does not override every regional, account or server-side restriction.
How do I completely block Firefox AI features?
Open Settings > AI Controls and enable Block AI enhancements. Firefox blocks covered AI tools and stops promoting new ones while the switch remains enabled.
Does Smart Window use Private Browsing history?
No. Mozilla says activity and data from Private Windows are excluded from Smart Window memories and browsing context.
Are Smart Window chats synced between devices?
No. Mozilla currently stores chats and memories locally and does not sync them across devices.
