# vercel-labs/emulate

Local API emulation for CI and no-network sandboxes

Repository: https://github.com/vercel-labs/emulate
Canonical: https://ross.abutalabs.com/products/emulate
Homepage: https://emulate.dev
Language: TypeScript
License: Apache-2.0
License Family: permissive
Last push: 2026-08-25T22:14:01+00:00

## Health v2 (maintenance only)
Score: 81/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 98, longevity 11
- inputs: {"age_days": 166, "days_push": 8, "days_rel": 14, "gap_med": 18, "n_releases_24m": 8}
- flags: young
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1609, forks 114 (observed 2026-08-28T04:05:10.597463+00:00)

## What it is
emulate is a zero-config CLI and programmatic library that runs stateful, production-fidelity local replacements for third-party APIs like Stripe, GitHub, Google, AWS, Slack, and more. It lets developers and CI pipelines point existing SDKs at localhost instead of real network services, with no API keys or Docker required.

## Use cases
- run integration tests against Stripe without a test-mode account
- emulate GitHub API locally for CI pipelines
- test OAuth flows offline with Google or Okta emulators
- develop against AWS APIs in a no-network sandbox
- reset emulator state between Vitest or Jest test suites
- seed deterministic test data via YAML config
- serve emulated APIs over trusted HTTPS with portless

## When to choose
- you need deterministic, stateful third-party API behavior in CI without network access
- you want your existing SDKs to work unchanged by just pointing them at localhost
- you need OAuth, webhooks, or protocol-faithful responses (AWS XML, Stripe signatures) locally
- you want zero-config startup with sensible defaults

## When to avoid
- you need exact production parity for edge cases or newly released API features
- you only need simple request/response mocking without state
- your tests depend on real rate limits, quotas, or live third-party data
- you need services not covered by the supported list

## Facets
- artifact type: cli-tool
- maturity: active
- function: mock-api, testing, http-server, cli, developer-tools
- domain: developer-tools, testing, apis
- platform: cli, cross-platform
- tags: api-emulation, offline-development, ci, sandbox, stateful-mocks, oauth-emulation, stripe, github, aws, automation, nodejs

## Member repositories
- vercel-labs/emulate (main) score 81

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:10.597463+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:51:19.730354+00:00, confidence not recorded.
  - readme: https://github.com/vercel-labs/emulate (fetched 2026-08-28T04:05:10.597463+00:00, sha 6eae91d77a89)
  - homepage: https://emulate.dev (fetched 2026-08-29T11:23:48.254166+00:00, sha b4cd132a1eac)
  - site_page: https://emulate.dev/docs (fetched 2026-08-29T11:23:48.264095+00:00, sha e058cb192006)
  - registry_npm: https://registry.npmjs.org/emulate (fetched 2026-08-29T11:23:48.266173+00:00, sha dd3a08c3f397)
- Data as of 2026-08-30T08:39:29.467469+00:00.