Puter Labs runs the real Firefox engine entirely in a browser tab via WebAssembly

Puter Labs has compiled Mozilla’s Gecko engine to WebAssembly, letting the genuine Firefox interface render and run inside an ordinary browser tab with no local install. Rather than a screenshot or reimplementation, it’s the actual browser engine executing client-side, with rendering optionally hardware-accelerated through WebGL and an experimental (and acknowledged-buggy) JIT path that translates JavaScript to WASM for extra speed.

Because a sandboxed WASM environment can’t open raw network sockets, page loads are routed through a Puter-hosted Wisp proxy server, and networking is wired up via Puter.js. That proxy is the project’s main practical caveat: it adds latency and means external sites are fetched through Puter’s infrastructure rather than directly, which carries privacy implications worth noting for anyone browsing real content through it.

The demo is best read as a proof-of-concept for running full desktop applications in the browser — thin-client and locked-down-environment scenarios where a browser tab is the only available runtime. It’s an impressive engineering feat, but the experimental JIT, proxy dependency, and expected bugs make it a lab curiosity rather than a daily driver for now.