Mockoon logo

Mockoon

Freemium

Desktop application for mocking REST and GraphQL APIs locally without any signup or server setup. Define endpoints, response bodies, status codes, and delays in a GUI, then run the mock server instantly. Useful for testing against APIs that are unavailable, unstable, or not yet built.

Visit websiteGitHub

Pricing

Freemium

Type

Community

// VERDICT

Reach for Mockoon when you want to design and run mock APIs visually in minutes, with a CLI for CI. Skip it when you need code-level stubs inside a JVM test suite or true contract testing.

Best for

Quickly spinning up realistic mock REST APIs from a desktop GUI, with no code, for development and testing.

Avoid when

You need code-defined stubs in a JVM test suite, or consumer/provider contract testing.

CI/CD fit

Mockoon CLI · Docker · GitHub Actions · GitLab CI

Team fit

Frontend teams · API teams · Anyone needing a quick mock

Setup

Easy

Maintenance

Low

Learning

Beginner

Licence

Freemium

// BEST FOR

  • Designing mock REST endpoints visually with no code
  • Standing up a fake API in minutes during frontend or integration development
  • Realistic responses with templating, rules and simulated latency/errors
  • Sharing mock definitions as files across a team
  • Running mocks headless in CI or Docker via the Mockoon CLI
  • Unblocking frontend work before the real API exists

// AVOID WHEN

  • You need code-defined stubs embedded in a JVM test suite (WireMock fits)
  • Consumer/provider contract testing is the goal (Pact fits)
  • Complex stateful scenarios beyond the GUI's rules
  • You want stubs derived directly from your test code
  • Deep request-matching logic is central
  • You're validating a real API rather than faking one

// QUICK START

npm install -g @mockoon/cli
mockoon-cli start --data ./mock-environment.json

// ALTERNATIVES TO CONSIDER

ToolChoose it when
WireMockYou want code-defined stubs in a JVM test suite.
JSON ServerYou want a zero-config fake REST API from a JSON file.
MockServerYou want a JVM-friendly standalone mock/proxy server.

// FEATURES

  • GUI-driven API mock creation — no code required
  • Response templating with Handlebars and dynamic data (Faker.js)
  • Request matching rules: method, path, headers, body
  • Latency simulation for realistic performance testing
  • CLI and Docker image for running mocks headlessly in CI

// PRIMARY USE CASES

  1. API STUBBING

    Replace an unstable third-party API or an unbuilt service with a local mock so UI or integration tests can run without real dependencies.

  2. ERROR PATH TESTING

    Configure a mock to return 429, 500, or 503 responses on demand to test how the application handles error conditions.

  3. FRONTEND DEVELOPMENT

    Give front-end developers a running API contract to build against before the back-end service is available.

// PROS

  • Works offline — no cloud account or external service needed
  • Fast to set up: running mock in under a minute
  • Free core tier covers most local testing needs
  • CLI mode makes it usable in CI pipelines

// CONS

  • Less powerful than WireMock for stateful or programmatic scenarios
  • No built-in support for record-and-replay from a live API
  • Team collaboration features are paid (Mockoon Cloud)
  • GUI-only configuration can be hard to review in code review

// EXAMPLE QA WORKFLOW

  1. Define mock routes and responses in the GUI

  2. Add templating, rules and simulated latency/errors

  3. Export the environment file and commit it

  4. Point the frontend or tests at the mock

  5. Run headless in CI/Docker via the Mockoon CLI

  6. Keep mock responses aligned with the real API