tl;dr: Cloudflare, VoidZero, and Owner.com are developing tsrs, a Rust port of the TypeScript compiler, in collaboration with the TypeScript team as part of the Oxc toolchain. Early benchmarks show tsrs is up to 8x faster and uses ~70% less memory than TypeScript 7.0, with Rust chosen primarily for its superior WebAssembly story (no GC overhead), enabling sandboxed dev environments in browsers, Workers, and embedded devices. The project aims to stay faithful to upstream TypeScript rather than fork it, using agents to track and sync changes similar to their Vinext/Next.js workflow.