Firefox in WebAssembly

A team compiled Firefox's Gecko engine to WebAssembly, enabling a full browser to run inside another browser via a WebSocket proxy. The project cost an estimated $25,000 in AI tokens from Anthropic's Claude Opus and Fable models, and required scaling servers to handle traffic from Hacker News. The demo supports end-to-end encryption and is available on GitHub.

Here's my blog, running in Firefox, running in WebAssembly, running in Chrome: They chose Firefox/Gecko because it has strong single-process support. The project took an estimated $25,000 of Claude Opus and Fable tokens, taking advantage of a Claude Max subscription plan. The demo funnels all traffic over a WebSocket protocol using the Wisp protocol https://github.com/MercuryWorkshop/wisp-protocol through Puter's server - a requirement to get this kind of thing to work because code running in browsers can't open arbitrary network connections. That proxying sounds expensive The team had to scale the servers up https://news.ycombinator.com/item?id=48926939 48936563 to handle the traffic during the Hacker News conversation about the project. Puter claim this supports end-to-end encryption and that looks to be true - I inspected the WebSocket messages and traffic to my own HTTPS site was encrypted whereas requests and responses to http://www.example.com/ were in cleartext. Here's the repo https://github.com/HeyPuter/firefox-wasm for firefox-wasm . theogbob/WebkitWasm https://github.com/theogbob/WebkitWasm is a similar project that compiles WebKit to WASM, but that one doesn't currently have an accessible online demo. Via Hacker News https://news.ycombinator.com/item?id=48926939 Tags: browsers https://simonwillison.net/tags/browsers , firefox https://simonwillison.net/tags/firefox , ai https://simonwillison.net/tags/ai , webassembly https://simonwillison.net/tags/webassembly , generative-ai https://simonwillison.net/tags/generative-ai , llms https://simonwillison.net/tags/llms , ai-assisted-programming https://simonwillison.net/tags/ai-assisted-programming , claude https://simonwillison.net/tags/claude , claude-mythos-fable https://simonwillison.net/tags/claude-mythos-fable