TypeScript in Go, Vite on Rolldown, Biome instead of ESLint and Prettier, uv on the Python side. In eighteen months most of the tools that used to be written in the language they process were replaced by native ones. I moved a monorepo across to all of them. This is the before and after, and the two places where the rewrite isn't a free win.
The Go port of the TypeScript compiler went GA on 8 July 2026, with an 8x to 12x speedup on full builds. I moved a six package pnpm monorepo across in an afternoon. This is what actually changed, what broke, and the one thing I'd check before you run the upgrade.
I moved commit messages, log triage, PR summaries, test naming and half a dozen other small jobs from a hosted API to an open-weight model on my laptop. Cost had nothing to do with it. For this kind of task a 30B model on a MacBook can't be told apart from the frontier, and I'd rather the data never left the machine.