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.

skills.sh installs: 873
GitHub stars: 61
last updated: Jul 14, 2026

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Install

$ npx -y skills add aradotso/trending-skills --skill vercel-labs-emulate --agent claude-code

Installs into .claude/skills of the current project.

Files

vercel-labs/emulate

Skill by ara.so — Daily 2026 Skills collection.

emulate provides fully stateful, production-fidelity local HTTP servers that replace Vercel, GitHub, and Google APIs. Designed for CI pipelines and no-network sandboxes — not mocks, real in-memory state with proper pagination, OAuth, webhooks, and cascading deletes.

Installation

# CLI (no install needed)
npx emulate

# Or install as a dev dependency
npm install --save-dev emulate

CLI Usage

# Start all services with defaults
npx emulate

# Start specific services
npx emulate --service vercel,github

# Custom base port (auto-increments per service)
npx emulate --port 3000

# Start with seed data
npx emulate --seed emulate.config.yaml

# Generate a starter config
npx emulate init

# Generate config for a specific service
npx emulate init --service github

# List available services
npx emulate list

Default ports: