When switched on, Firefox routes browser traffic through a proxy network that substitutes the user's IP address before requests reach their destination. The websites visited see the proxy's address, not the user's real one, Mozilla explains.

Firefox already encrypts traffic with HTTPS, and IP masking adds a second layer on top of that. HTTPS conceals the content of your traffic; masking your IP conceals your location and identity from the sites you visit, reducing one of the primary signals companies use to track users across different websites, per Mozilla.

A small toggle to the right of the search bar handles activation. No separate app, no extension required. Mozilla has been testing the feature with select users and says activation may require a Mozilla account for some, FindArticles reported four days ago.

Two situations where the protection matters most in practice:

• Public Wi-Fi: The proxy makes it significantly harder for others on the same network to see which sites you're visiting, Mozilla notes.
• General browsing: Hiding your IP removes one of the primary signals companies use to correlate browsing activity across sites.

One practical detail worth knowing upfront: if you hit the 50GB monthly cap, IP protection pauses until the next billing cycle. Firefox will prompt you to confirm before continuing without it, so browsing doesn't accidentally proceed unprotected, according to Mozilla. For standard web use, shopping, and online banking, 50GB is more than enough. Heavy browser-based video streaming will exhaust it mid-month, Gizmodo noted five days ago.

One notable constraint: the proxy automatically connects to a nearby endpoint rather than letting users choose a specific country. That limits its usefulness for anyone hoping to access geo-restricted content, FindArticles noted. Technically, the architecture is closer to Apple's iCloud Private Relay than to a conventional VPN. Traffic routes through a proxy, not a full encrypted tunnel across all apps and services. Mozilla markets it as a VPN; the gap between that label and the underlying reality is worth keeping in mind.

Mozilla states directly that the feature "does not offer full device protection," and protection stops at the browser window, per Mozilla's announcement today. Every other app on the device email clients, streaming services, cloud backup software, game launchers, system-level network activity continues using the user's real IP address.

Cybersecurity expert Jacob Kalvo, CEO of Live Proxies, put the core issue plainly to CNET five days ago: "The fundamental limitation is scope it only protects browser traffic, not apps, system processes or other network activity. That creates a false sense of full protection for less technical users."

IP masking is also only one layer of privacy, not the whole picture. The feature does not stop tracking via cookies or browser fingerprinting; those require Firefox's own Enhanced Tracking Protection settings or stricter privacy configurations, according to research published in January. Turning on the built-in VPN while leaving other tracking protections untouched reduces one exposure while leaving others open.

For geo-restriction bypassing, the picture is equally clear. Streaming platforms check for VPN and proxy use at the connection level, and browser-based proxies are among the easier signals to detect and block. Users hoping to unlock region-restricted content through this feature should expect it not to work, Gizmodo reported five days ago.

On the question of trust, Mozilla preemptively addresses the standard concern about free VPNs: the feature does not sell browsing data and does not inject advertising into traffic, according to Mozilla. That claim is more credible than most free VPN providers can offer, given Mozilla's track record and stated data principles. Mozilla's overall VPN technology has also been independently audited by security firm Cure53, CNET noted five days ago. That prior audit doesn't automatically extend to a new implementation, though.

No independent audit specific to the built-in browser feature had been published as of today. ZDNET flagged that gap explicitly, noting there have been no significant security concerns with the existing paid solution, which may offer some basis for confidence. A day-one audit gap is normal for a beta launch. Whether one follows will be the clearest signal of how seriously the broader privacy community should take the trust claims.

Here's a simple test: if the activity happens entirely inside Firefox, and the goal is IP masking rather than location spoofing or device-wide protection, this feature is probably enough. If the goal extends beyond the browser window in any direction, it isn't.

The 50GB monthly cap covers shopping, banking, and everyday reading with room to spare, Mozilla says. Multiple outlets describe it as genuinely generous for users without a paid VPN subscription, per ZDNET today. It's suited for casual browsing and users who want to protect their online sessions or simply learn what IP masking does.

If you already subscribe to a standalone VPN service, ZDNET advises against canceling it on the basis of this launch. A browser proxy is not a substitute for device-wide coverage, server choice, or the encryption protocol options that independent VPNs offer.

For users who discover they need broader coverage, Mozilla's separate paid product Mozilla VPN protects up to five devices for $4.99 per month with servers across more than 30 countries, ZDNET reported today. The free browser feature is a natural starting point for users who want to understand what VPN protection means before deciding whether to pay for more of it.

Use it if:

• You want IP masking while browsing Firefox on public Wi-Fi, doing sensitive browsing, or reducing cross-site tracking
• You don't need to protect non-browser apps or access geo-restricted content
• You don't currently have a paid VPN subscription

Skip it, or don't rely on it, if:

• You need device-wide protection across all apps and services
• Streaming geo-unblocking is the goal streaming platforms will detect and block it
• You already pay for a standalone VPN with server choice and full-device coverage
• You need independently verified privacy assurances beyond Mozilla's own statements at beta launch

Firefox's free built-in VPN is the most accessible introduction to IP masking available in any major browser today. No app, no extension, no subscription 50GB a month, single click, per Mozilla. For everyday users who want to obscure their IP from websites and trackers while browsing, it works for that purpose.

The protection ends at the browser window. Every other app, process, and network connection on the device is unaffected, and the "VPN" label is likely to mislead users who don't know the difference a concern security professionals have raised directly, CNET reported five days ago.

The beta currently covers four countries and desktop only. Mozilla has signaled expansion across future releases without committing to a specific timeline, according to the company. Useful browser privacy tool worth using, worth understanding precisely for what it is.