The Pulse: What can we learn from Bun’s rapid Rust rewrite with AI?
Source
Gergely Orosz
Author
Gergely Orosz
Date
Why it matters
Most AI-coding takes stay theoretical; this one crunches the actual numbers on a real migration — $165K and 11 days to move Bun from Zig to Rust, versus the 1-2 years it would've taken by hand. The kicker is the precondition: it only works because the project was thoroughly tested. Read it if you're weighing a large-scale AI-assisted rewrite and want a realistic sense of the cost, speed, and test-coverage bar you'll need to clear first.
Key quotes
“To a sceptic, spending $165K to migrate Bun from Zig to Rust sounds very expensive. But to a realist, shortening a 1-2 year migration down to 11 days opens amazing new opportunities for devs.”
“However, a thoroughly-tested project is required to pull it off.”
