Most people who enable the built-in VPN in Firefox assume they are protected. They are - but only partially, and the gap between what they believe they have and what they actually have is where privacy problems begin. After testing Firefox VPN across speed, leak protection, and streaming performance, a clear picture emerges: it works as described, but its description covers far less ground than users typically expect.
What Firefox VPN Actually Is - and What It Is Not
The Firefox VPN is a browser-level privacy tool, not a system-wide VPN service. It encrypts traffic inside the Firefox browser and masks your IP address from the websites you visit. Everything else - other apps, background system processes, operating system connections - remains entirely unprotected and fully visible to your internet provider or anyone monitoring the network.
This distinction matters enormously. A dedicated VPN service creates an encrypted tunnel for all data leaving your device. Firefox VPN creates an encrypted tunnel only for your browser tab. If you open a streaming app, a torrent client, a messaging platform, or virtually any software outside of Firefox while connected, that traffic travels without any protection whatsoever.
The underlying infrastructure is Mullvad VPN, which has a strong reputation for privacy. That is a meaningful positive. But Mozilla has layered a stripped-down interface on top of it that removes nearly all of Mullvad's actual functionality. There is no server selection, no protocol choice, no kill switch, no split tunneling. You get a toggle and a monthly data cap.
Speed and Leak Test Results: Solid Where It Functions
Testing showed a speed reduction of roughly 10 to 17 percent with the VPN active. Download speeds dropped from approximately 428 Mbps to 377 Mbps, and upload speeds fell from 337 Mbps to 279 Mbps. Latency actually improved slightly, which is unusual and likely reflects favorable server routing at the time of the test rather than a structural advantage.
A speed loss in this range is considered acceptable by most VPN benchmarks. In everyday browsing, the difference is imperceptible. Pages load without delay, video streams without buffering, and nothing about the experience signals that a VPN is active.
Leak protection tests produced clean results. Both WebRTC leak tests and standard IP and DNS leak checks confirmed that the real IP address was not exposed during active sessions. For users on public Wi-Fi - in airports, cafes, hotels - this offers genuine, functional protection against opportunistic traffic interception. That is not a trivial benefit, and it should not be dismissed.
What the test also confirmed is that the privacy policy claims a no-logs approach, but there is no published independent audit to verify it. That absence places Firefox VPN well behind providers like Mullvad itself, ExpressVPN, or NordVPN, all of which have submitted to external security audits with published results.
Streaming Works, Until You Need Flexibility
Streaming through the Firefox VPN functioned without issues during testing. A U.S.-based server connection loaded the U.S. Netflix library without triggering detection or blocking. Video quality was unaffected, and there was no buffering during playback.
The limitation here is structural rather than technical. Because Firefox VPN provides no server selection, users cannot choose a server in another country to access a different regional content library. You are routed wherever Firefox assigns you, with no ability to override it. This means the feature works adequately for users who simply want to stream in their home market with some traffic privacy, but it is entirely useless for accessing international libraries, bypassing geographic content restrictions, or circumventing regional censorship.
For travelers or users in countries with restricted internet access, this is a significant gap. A tool with no location control cannot address location-based blocking, regardless of how well it performs on other metrics.
Who Should Use It and Who Needs Something Better
Firefox VPN is worth enabling for users who want a lightweight, zero-effort privacy layer for casual browsing. It requires no account, no configuration, and no expertise. For someone browsing on an unfamiliar network or handling sensitive personal information through a web browser, it provides a meaningful improvement over no protection at all.
It is not suitable for anyone with more specific privacy requirements. Users who need protection across all their applications, travelers who rely on location flexibility, journalists or researchers working in sensitive contexts, or anyone seeking verifiable no-logging guarantees will find Firefox VPN insufficient.
- Protects only browser traffic - all other apps remain exposed
- No server selection, no kill switch, no split tunneling
- No independent audit of its no-logs policy
- Mullvad infrastructure operates under Swedish jurisdiction within the 14 Eyes intelligence-sharing group
- Monthly data cap limits heavy or continuous use
The broader issue is one of perception. Browser-integrated privacy tools tend to generate a false sense of comprehensive protection. Users who enable Firefox VPN and assume their device is secure are more exposed than they realize. That gap - between perceived safety and actual coverage - is where the real risk lives. Firefox VPN is not a bad tool. It is simply a very limited one, and its limitations are easy to misunderstand.
