Emulate overview

Open source (Apache-2.0) by Vercel Labs — github.com/vercel-labs/emulate (npm `emulate`). CLI that provides offline, stateful local emulation of ~11 popular third-party APIs (Stripe, GitHub, Google, AWS, Slack, and others) — no network, API keys, or real accounts needed. Emulates authentic protocols (OAuth with RS256 tokens, AWS XML responses) and persists state across requests (create repos, push commits, charge cards). Deterministic and CI-ready. Services run on HTTPS localhost endpoints (e.g. `https://stripe.emulate.localhost`) and integrate with Portless (`npx emulate --portless`); SDKs are pointed at the local host/port (e.g. `localhost:4010`). Usage: `npx emulate --service github,stripe`; programmatic `import { createEmulator } from "emulate"`; Next.js adapter via `npm install @emulators/adapter-next @emulators/github`.