podcasts / Ryan Peterman / episode / question
Question

How does Stephen Toub decide whether a codebase rewrite or migration is worth doing?

Answered from Microsoft Distinguished Eng: Why And How To Port Your Entire Codebase to Rust | Stephen Toub · Ryan Peterman · 2026-11-02

Stephen Toub said a business rewrite needs a clear return on investment: what value it delivers, what it costs and whether the trade is worth it. He cited customers moving from .NET Framework to .NET Core who could weigh, say, $3 million a year in saved server costs against a developer-year of porting, and his own .NET regex engine work, where two weeks making patterns four times faster could be priced against a service's spend.

Source: our own transcription of the episode. The full conversation is on Ryan Peterman (2026-11-02). Read the whole episode summary →

▸More from this episode

Q1Why did Stephen Toub rewrite the GitHub Copilot runtime from TypeScript to Rust?Q2Why did Stephen Toub choose Rust over C#, Go or Java for the Copilot runtime?Q3How did Stephen Toub's incremental Copilot port compare with Bun's big-bang Rust rewrite?Q4How did Stephen Toub catch regressions when AI agents ported the Copilot codebase to Rust?Q5What did Stephen Toub say about AI agents changing tests to make code pass?Q6How did Stephen Toub review hundreds of thousands of lines of AI-written code?Q7How much did Stephen Toub's AI-driven Copilot Rust port cost in tokens and time?
Transcribe your links. Paste a YouTube, Google Drive or podcast link and WhipScribe gives you the transcript. Transcribe a link →