
Microsoft Distinguished Eng: Why And How To Port Your Entire Codebase to Rust | Stephen Toub
Stephen Toub is a Distinguished Engineer at Microsoft who single-handledly rewrote the GitHub Copilot runtime (400,000-line codebase) in Rust. We talked about why/how he did it, how Rust compared with other languages, and everything he learned in the process. • My ergonomic keyboard project I mentioned, you can follow along here: https://read.compose.llc/ • The Kickstarter page for it: https://www.kickstarter.com/projects/ryanlpeterman/compose-simple-ergonomics-beautifully-done Podcast links: • YouTube: https://www.youtube.com/watch?v=PLMOVlZC4eU • Apple: https://podcasts.apple.com/us/podcast/the-peterman-pod/id1777363835 • Transcript: https://www.developing.dev/p/e073-stephen-toub Thank you to this episode's sponsor for supporting my work: • WorkOS: makes your app Enterprise Ready with easy to use APIs to add SSO, SCIM, RBAC, and more in just a few lines of code, check them out at https://workos.com/ Timestamps: (00:00) Intro (01:06) Why the Copilot runtime needed a Rust port (05:38) Why he chose Rust (11:28) Discussing rollout strategies (21:57) How he caught regressions (32:08) Guiding the agents (42:11) Catching regressions before prod (45:16) Which models he used (50:03) The end benefit and costs (01:03:24) When to do a full rewrite (01:06:40) Career learnings on the way to Distinguished (01:16:00) Top technical book recommendation (01:17:49) Advice for young engineers (01:21:00) Outro Where to find Stephen: • GitHub: https://github.com/stephentoub • X: https://twitter.com/stephentoub • LinkedIn: https://www.linkedin.com/in/stephen-toub-75979745/ Where to find Ryan: • Newsletter: https://www.developing.dev/ • X/Twitter: https://x.com/ryanlpeterman • LinkedIn: https://www.linkedin.com/in/ryanlpeterman/ • Threads: https://www.threads.com/@ryanlpeterman • Instagram: https://www.instagram.com/ryanlpeterman • TikTok: https://www.tiktok.com/@ryanlpeterman Referenced in this episode: • Stephen Toub’s post on porting the GitHub Copilot runtime to Rust: https://github.blog/ai-and-ml/generative-ai/migrating-the-github-copilot-runtime-to-rust-using-copilot/ • Jarred Sumner’s post on porting Bun to Rust: https://bun.com/blog/bun-in-rust • Code: The Hidden Language of Computer Hardware and Software: https://www.charlespetzold.com/code/index.html


















