Vercel Labs Emulate

This drops production-like Vercel, GitHub, and Google API servers into localhost for CI and offline testing. Not mocks,actual stateful emulation with pagination, OAuth flows, webhooks, and proper resource relationships. You seed it with YAML or inline config, point your test suite at localhost:4000, and your integration tests run without network calls or rate limits. The GitHub emulator even validates JWT signatures for GitHub Apps. It's overkill for basic unit tests, but if you're testing deployment pipelines, OAuth integrations, or webhook handlers, this beats VCR cassettes and janky mocks. The state resets between tests, so you get clean runs without Docker overhead.