Firefox's free built-in VPN swaps your IP for a proxy's for browser traffic only. Here's what it hides, what sites still see, and how to test it yourself.
Firefox's built-in VPN is a free, browser-level feature from Mozilla that routes your Firefox browsing through a proxy network, so the sites you visit see the proxy's IP address instead of yours. It covers Firefox only, not your whole device, and it does nothing about your browser fingerprint, cookies or logged-in accounts. If you landed here after spotting browser.ipProtection.* entries in about:config: that is the Firefox feature (Mozilla calls it IP protection), not Chrome's IP Protection, which is a different product with a different scope.
Key Takeaways
- Firefox's built-in VPN is free for 50 GB of VPN browsing per month, shared across desktop and mobile; when the allowance runs out, IP protection pauses until the next cycle, and Firefox asks you to confirm before continuing without it.
- It protects browsing in Firefox only. Mozilla states it "does not offer full device protection"; the paid Mozilla VPN is the full-device option.
- Sites see the proxy's IP address rather than yours. Your browser fingerprint, cookies and logins are unchanged, so a site can still recognise you.
- A proxy IP can look like a VPN or datacenter address, so some sites may challenge or flag it.
- Mozilla's announcements don't describe WebRTC or DNS handling, so test it yourself with the VPN/proxy check and the IP intelligence tool, with the VPN on and off.
The browser.ipProtection confusion
Search data shows a pattern: people who find browser.ipProtection.* preferences in about:config end up reading about Chrome. The namespace belongs to Firefox. These are internal preferences that people stumble on while looking for the feature; Mozilla does not document them as a supported switch, so don't flip them by hand. The supported way to turn the VPN on is the toolbar and settings toggle described in Mozilla's announcement.
| Firefox built-in VPN | Chrome IP Protection | |
|---|---|---|
| What it proxies | Your browsing in Firefox | Only certain third-party requests, in Incognito |
| Who turns it on | You, with one click | Tested on a limited set of Incognito users, who could turn it off |
| Allowance | 50 GB per month | Not applicable |
| Status | Beta rollout from March 2026 (Firefox 149) | Retirement announced in October 2025 |
The Chrome column comes from our Chrome IP Protection explainer.
What Mozilla actually says
Everything below comes from Mozilla's own posts: A free VPN you can trust, now built into Firefox, New in Firefox 151 and What's new in Firefox mobile.
- How it works: once on, Firefox routes browsing traffic through a proxy network that replaces your IP address before it reaches a website.
- Allowance: 50 GB of free VPN browsing each month, counted across desktop and mobile. At the limit, protection pauses until the next cycle, and Firefox requires you to confirm before continuing without the VPN.
- Scope: browsing in Firefox. It is "not full device protection"; the standalone Mozilla VPN subscription covers the whole device.
- Rollout: a beta for desktop users starting in Firefox 149, initially in the United States, United Kingdom, Germany and France. Firefox 151 added location selection for users in the U.S., U.K., France, Germany and Canada. Android rollout began on July 28, 2026.
- Data practices: Mozilla says it does not sell browsing data and does not inject ads into your traffic.
Availability changes between releases, so check Mozilla's posts for the current country list rather than relying on this page. This article does not name the proxy operator or give server counts, because those posts don't.
What websites can still see
A VPN changes where a request appears to come from. Most tracking never relied on that.
What changes: your public IP, and so your IP-based location, ISP and network type. Check the before and after with the IP intelligence tool.
What doesn't change:
- Your browser fingerprint. User agent, screen, fonts, canvas and WebGL output are all still sent. VPNs and fingerprinting explains why hiding an IP and defeating tracking are separate jobs. See your own exposure with the fingerprint check.
- Cookies and logins. Signed in to an account, you are still you. A new IP doesn't clear anything.
- Your time zone and language. With a location selected, an exit country that disagrees with your system time zone is a classic inconsistency; see time zone and IP mismatch.
- The fact that you use a proxy. Proxy and VPN exit addresses are often recognisable as such. A site may flag or challenge them, as covered in how websites detect VPNs. Whether a given site does is up to the site.
Leaks: test, don't assume
Mozilla's posts don't say how WebRTC or DNS lookups are handled, so neither this article nor anyone else outside Mozilla should assert it for you. Measure it:
- Open the IP intelligence tool in Firefox with the VPN off and note the IP, ASN and location.
- Turn the VPN on, reload, and compare. The IP and ASN should change.
- Run the VPN/proxy check, which includes a WebRTC leak test, with the VPN on. A local or real public IP appearing there would be a leak worth knowing about.
- Compare your results against our guides to WebRTC leak protection and DNS leak prevention. For the underlying API, see MDN's WebRTC API documentation.
Because the VPN applies to Firefox browsing, repeat the test in Firefox itself; a check in another browser will show your real IP.
Where it fits among privacy tools
- iCloud Private Relay splits trust across two operators for Safari traffic and doesn't let you pick a country; see iCloud Private Relay explained.
- A full VPN app covers every app on the device and usually lets you pick a server, at the cost of trusting one provider with everything and some speed; see proxy types explained and why a VPN slows your connection.
- Firefox's built-in VPN sits between them: one click, free up to a cap, browser-only.
For a broader map of what each option hides, read the privacy tools comparison. This is an explainer, not a ranking of VPN services.
Frequently Asked Questions
Is Firefox's built-in VPN really free?
Mozilla offers 50 GB of VPN browsing per month at no cost. After that, protection pauses until the next monthly cycle, and Firefox asks you to confirm before browsing without it.
Does it protect my whole device?
No. It covers browsing in Firefox. Mozilla points to its paid Mozilla VPN for protection across other apps.
What is browser.ipProtection in about:config?
Internal Firefox preferences connected to the IP protection feature. Mozilla doesn't document them as a supported control, so use the in-browser toggle instead.
Can websites tell I'm using it?
They see a proxy IP rather than your home address, and such addresses are often recognisable as VPN or datacenter ranges. Some sites may flag them; others won't care.
Does it stop browser fingerprinting?
No. Fingerprinting uses browser and device attributes, not your IP. Test what your browser reveals with the fingerprint check.
Conclusion
Firefox's built-in VPN is a convenient way to keep your real IP from the sites you visit in Firefox. It is not a full-device VPN and not a defence against fingerprinting or cookies. Run the IP intelligence tool and the VPN/proxy check with it on and off to see what a website actually sees.
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