What happened
On 8 July 2026 Microsoft released TypeScript 7.0, a reimplementation of the compiler and language service in Go. The team reports full-build speedups typically between 8× and 12× — for example, type-checking VS Code fell from 125.7s to 10.6s (11.9×) — with shared-memory multithreading and native code speed.
Why it matters
Compiler latency is a tax on every edit, CI run and editor interaction. A ~10× cut changes what large TypeScript monorepos can do: faster feedback loops, cheaper CI, and viable type-checking on codebases that had outgrown the JavaScript-based compiler.
The speed is the headline; the migration is the work. 7.0 is effectively a rewrite with behavior and configuration changes, so the Staff move is to pilot it against your real build, catch the differences from the old compiler, and sequence the rollout — not to flip it on across every repo at once.
Your TypeScript type-check dominates CI time. How would you evaluate migrating a large monorepo to the native compiler, and what would you measure?
Probes build-system reasoning and migration risk, not syntax.