Firefox's market share has been shrinking for years, and it's easy to read that as Mozilla losing ground technically too. It hasn't. In 2026 alone, Firefox shipped privacy defaults no other major browser matches out of the box, kept an extension API Chrome walked away from, and its engineers are still pushing core pieces of the web platform forward — some of it inside Firefox, some of it in a rendering engine Mozilla doesn't even own anymore. Here's what's actually true right now, not the reputation.
The privacy defaults nobody else ships by default
Firefox 151 (May 2026) moved enhanced anti-fingerprinting into the default "Standard" protection level — previously it was a Strict-mode-only option most people never turned on. Mozilla's own measurement puts the effect at roughly a 14% drop in uniquely identifiable users overall, and about 49% on macOS specifically, where fingerprinting techniques tend to work unusually well. The same release extended local network access restrictions to every user, not just Strict-mode users: a site now has to ask before it can probe devices on your home network, matching where Chrome and Edge eventually landed too.
A dedicated "end private session" button — a fire icon next to the address bar — wipes the current Private Browsing session's history, cookies, and cache and starts a clean one, without closing the window first.
Security: fast patches, and an extension API Chrome gave up on
Firefox 151 also shipped a fix for CVE-2026-8953, a sandbox-escape use-after-free bug in the Disability Access APIs component, patched with no reports of it being exploited in the wild before disclosure — the kind of unglamorous, on-schedule patching that matters more than any single feature. On the extensions side, Firefox is the one major browser that kept the full blocking webRequest API alive under Manifest V3, alongside the newer declarativeNetRequest system, rather than deprecating it the way Chrome did. Practically, that's why content blockers like uBlock Origin still run at full strength in Firefox while losing capability in Chrome.
Passkeys got more usable too: WebAuthn Related Origin Requests, shipped this year, let a passkey registered on one domain sign you in on a related domain without re-registering — with Firefox surfacing exactly which site is asking, rather than approving it silently.
The engineering most users never see
Mozilla was one of the first browser vendors to implement WebAssembly and helped define WASI, the WebAssembly System Interface — the spec that lets Wasm modules do things like file and network I/O outside the browser sandbox, not just crunch numbers inside it. A WASI 0.3 release is expected in 2026, with 1.0 targeted for late 2026 or early 2027. On the graphics side, Firefox shipped WebGPU by default on Windows in Firefox 141 and added Apple Silicon macOS support in Firefox 145; Linux, Android, and Intel Mac support are still rolling out through 2026 — WebGPU replaces the aging WebGL with direct access to compute shaders and modern GPU memory management.
Servo — the Rust-based rendering engine Mozilla Research started building in 2012 — isn't a Mozilla project anymore. Stewardship moved to the Linux Foundation in 2020 and then Linux Foundation Europe in 2023. It's not inside Firefox, but it's still the clearest evidence of Mozilla's engineering DNA spreading past Mozilla itself: the current focus is turning it from a research project into a production-ready engine other applications can embed.
What's coming: Project Nova and an actual public roadmap
Mozilla published a real public roadmap this year — upcoming work broken out by category and platform instead of vague promises — alongside "Project Nova," a visual and structural redesign rolling out through 2026 aimed at privacy, usability, performance, accessibility, and customization all at once. Concretely, that's shipped as a redesigned Settings layout and a Blocked Tracker Widget showing what's actually been stopped, with Tab Groups (already on desktop) rolling out to Android now and iOS later in 2026.
Still on the roadmap: customizable keyboard shortcuts, native Multi-Account Containers (currently a separate extension) built into the browser directly, in-browser PDF editing that can split, merge, and reorganize documents without a separate app, a mobile Power Saving Mode, and Mozilla's VPN expanding from desktop-only to iOS and Android.
Where Firefox is being deliberately careful about AI
Firefox added a dedicated AI Controls section to Settings in version 148 (February 2026), and the roadmap includes a full kill switch to turn AI features off entirely — not just individually. The AI features themselves are opt-in rather than default-on: "Quick Answers" gives voice-activated AI responses with source citations attached, and "Smart Window" is an optional, separate private-browsing-style AI tool for comparing information, now open without a waitlist. It's a narrower AI footprint than most competitors ship, and that narrowness looks deliberate rather than a resourcing gap — consistent with a browser whose whole pitch is not doing things to you by default.
Is Firefox actually more private than Chrome by default, or is that just reputation?
By default, yes on several concrete measures: Standard-mode anti-fingerprinting (Chrome has no equivalent built in), local network access permission prompts, and Enhanced Tracking Protection blocking third-party trackers out of the box without extensions.
Does Firefox still support ad blockers properly after Manifest V3?
Yes — Firefox kept the full blocking webRequest API alongside Manifest V3's declarativeNetRequest, so extensions like uBlock Origin keep their original filtering capability. Chrome deprecated blocking webRequest, which is why the Chrome Web Store version of uBlock Origin lost functionality.
Is Mozilla still building Servo?
Not directly — stewardship moved to the Linux Foundation in 2020 and then Linux Foundation Europe in 2023. It's a separate project now, though one that started at Mozilla Research and still shares a lot of its engineering culture.
Firefox isn't trying to out-feature Chrome. It's betting that shipping privacy protections on by default, keeping an extension API that gives users real control, and treating AI as opt-in rather than ambient are worth more than winning every spec race. The 2026 roadmap — Project Nova, WebGPU rolling out platform by platform, an actual public list of what's coming next — suggests Mozilla is still willing to fund that bet.