I’m building a setup to mock external APIs for development, what should I use?

If you’re building a setup to mock external APIs for development, the best choice depends on whether you want something code-based, record/replay, or service virtualization.

Good options by use case

1. WireMock

• Great for HTTP/REST APIs
• Supports request matching, stubbing, delays, faults, and response templating
• Works well locally, in Docker, and in CI
• Good default choice for many teams

2. Mockoon

• Very easy to set up
• GUI-driven, fast for local development
• Great if you want to create mock APIs without much code
• Best for lightweight dev mocks

3. MSW (Mock Service Worker)

• Best for frontend development
• Intercepts browser/network requests at the service worker level
• Lets you mock APIs without changing app code
• Excellent for React/Vue/Angular/web apps

4. Prism

• Useful if you have an OpenAPI spec
• Can generate mock responses from your API schema
• Good for contract-first development

5. Postman Mock Servers

• Convenient if your team already uses Postman
• Simple for sharing mock endpoints
• Fine for basic mocking, less ideal for complex behavior

6. LocalStack

• Best if you need to mock AWS services specifically
• Simulates many AWS APIs locally
• Useful for cloud-heavy development

My recommendation

• For backend/API development: start with WireMock
• For frontend development: use MSW
• For quick local no-code mocks: use Mockoon
• If you have OpenAPI specs: use Prism

If you want a practical setup

A common stack is:

• WireMock for stable backend integration mocks
• MSW for frontend/browser-specific API mocking
• Docker Compose to run mocks locally and in CI

If you tell me:

1. your language/framework,
2. whether this is for frontend, backend, or both,
3. and whether your APIs are REST, GraphQL, or gRPC,

I can recommend the best tool and a starter setup.