Emulate

lastmod 2026-03-24created 2026-03-243 edits

Run full replicas of the GitHub, Vercel, and Google APIs locally

About

• A local API emulator made by Vercel for CI or network-restricted environments
• Not a simple mock; it has the same state and response structure as real production
• A single npx emulate starts Vercel (4000), GitHub (4001), and Google (4002)
• The CLI can select services, set ports, inject seed data, and generate config
• Can also be controlled directly in test code by calling createEmulator() via the Node API
  • Supports automatic initialization, reset, and shutdown in Vitest/Jest environments
• Configure users, teams, projects, and OAuth apps with config.yaml or JSON
• Reproduces GitHub Apps, OAuth, and even Webhook events as if they were real
• Implements all major REST endpoints of Vercel, GitHub, and Google
• Fully stateful in-memory Store structure with built-in CRUD, filtering, and pagination
• A tool for local integration testing, CI simulation, and OAuth flow verification

See also

• GitHub
• Vercel
• Google API

Favorite site

• Github - vercel-labs/emulate
• emulate - Run full replicas of the GitHub, Vercel, and Google APIs locally | GeekNews