WebUSB extension brings native USB access to Firefox — with a little help from a native stub

What it does

A new Firefox extension adds WebUSB support by linking the browser to a small native helper program. The extension itself communicates with that helper via Firefox's native messaging feature, enabling web pages to talk to USB devices in browsers that don’t natively support WebUSB. Want the convenience of in-browser device access without switching to Chromium? Now you can—though there’s a catch.

How it works and what you need

You install two pieces: the Firefox extension (.xpi or a temporary dev install) and a separate "native stub" program that sits on your machine. Prebuilt binaries are provided for macOS (x86_64, ARM64), Linux (x86_64, aarch64), and Windows (AMD64, ARM64), or you can build the native stub from source (it’s written in Rust). The native component handles the actual USB plumbing; the extension handles the browser-facing API.

It has been reported that the default installer trips up on unusual setups — things like shared *nix home directories across different architectures or Windows roaming profiles. The root cause is the native manifest mechanism and its use of absolute paths, so if you’re in one of those edge cases you’ll likely need an ad‑hoc workaround. There are also platform requirements: macOS 10.15+, Windows 10+, and recent Linux kernels with specific USBDEVFS features and a udev‑like daemon.

Why it matters (and a quick reality check)

This fills a gap for Firefox users who want WebUSB-style workflows without switching browsers. That’s big for hardware hackers, device makers, and web apps that talk directly to peripherals. But remember: you’re trusting a native binary to bridge browser and device—security and review practices matter. It’s a clever, pragmatic fix. Not seamless, not zero-trust, but useful. If you like poking under the hood, this one’s for you.

Sources: github.com/arcanenibble, Lobsters