What should I use for mocking APIs during development?

For mocking APIs during development, the best choice depends on whether you want a quick local fake server, a contract-based mock, or a full-featured testing tool.

Good options

1. Mockoon

• Best for: quick local API mocking
• Pros: very easy to use, desktop app + CLI, no backend needed
• Great if you want to define endpoints and return static/dynamic responses fast

2. Postman Mock Servers

• Best for: teams already using Postman
• Pros: easy setup from collections, useful for sharing mocks
• Good for: lightweight mocking without extra infrastructure

3. MSW (Mock Service Worker)

• Best for: frontend development and browser-based apps
• Pros: intercepts network requests at the browser/service-worker level, very realistic, works well with React/Vue/etc.
• Great when you want your app to “think” it’s talking to a real API

4. WireMock

• Best for: more advanced mocking, backend teams, integration tests
• Pros: powerful, supports request matching, templating, stateful behavior
• Good if you need richer behavior than simple static mocks

5. JSON Server

• Best for: very fast prototyping
• Pros: minimal setup, turns a JSON file into a REST API
• Good for demos and early development, but less realistic than others

6. Prism

• Best for: OpenAPI/Swagger-driven mocking
• Pros: can generate mocks from an OpenAPI spec
• Great if your API is spec-first and you want mocks aligned with the contract

Quick recommendations

• Frontend app: use MSW
• Need a local fake API fast: use Mockoon
• Have an OpenAPI spec: use Prism
• Need advanced matching/stateful behavior: use WireMock
• Already in Postman: use Postman Mock Servers

If you want the simplest answer

• Frontend development: MSW
• Backend or API prototyping: Mockoon
• Spec-driven development: Prism

If you tell me your stack (frontend/backend, language/framework, REST vs GraphQL, and whether you have an OpenAPI spec), I can recommend the best one specifically.