Cloudflare just made it possible to run real, unmodified Rust systems code - including async Tokio applications - directly on its Workers platform.
Cloudflare announced an experimental preview of Emscripten target support for wasm-bindgen, the open-source toolchain that compiles Rust into WebAssembly for its V8-based Workers runtime. The project traces back over a year to Google engineers who needed Emscripten and wasm-bindgen to cooperate instead of fighting over who controls the JavaScript build output, and a new -sWASM_BINDGEN configuration finally lets both toolchains produce bindings side by side. Cloudflare then extended that groundwork with Tokio support, tackling a harder problem: Workers run single-threaded inside a JS event loop, while Tokio's async runtime expects to block and park real threads. As proof, Cloudflare got Pumpkin, a Rust-native Minecraft server, running inside a Durable Object using real TCP sockets.
That matters because it closes a real compatibility gap for Rust on Workers - libraries as low-level as libc, socket2, and Mio needed only small patches, not rewrites, to work with the Emscripten target. Cloudflare says its Tokio fixes are being upstreamed rather than kept proprietary, so any project using wasm-bindgen and Emscripten together eventually inherits the same support. The Minecraft server is the flashy demo, but the quieter story is a serverless vendor rewriting async Rust's plumbing so it behaves on a platform it was never designed for.
It's still an experimental preview riding on patches that haven't fully landed upstream, so treat running a Minecraft server as a proof of concept, not a production promise.