5-15x faster on real suites

Migration takes 30 minutes, almost drop-in

mock.module and spyOn with auto restore

Inline and file snapshots without plugins

Built-in coverage with CI threshold gates

Stay on Vitest only for browser mode

Most JavaScript test runners are slow because they were built on top of bundlers that were never meant to run tests. Vitest stacks on Vite, Jest stacks on Babel, and both pay a tax in cold start, transform pipelines, and worker spin-up. For years I accepted this. A 1500-test backend suite that takes 22 seconds locally and 48 seconds on CI felt normal. Then I moved a few projects over to Bun's built-in bun test runner and the numbers stopped feeling normal. The same suite finished in 3.1 seconds locally. CI dropped to 6 seconds. No config file. No plugin chain. The API is the same as Vitest, so the migration was almost a find-and-replace.…