Free Mock API Generator Create mock APIs in seconds
The mock API tool for developers. Create mock REST API endpoints instantly, generate realistic fake JSON with Faker.js and AI, and simulate any response — no backend needed.
Trusted by 5,000+ developers · free plan, no credit card
// type a requestTrusted by +5000 developers from startups to enterprise
From zero to a working mock API in under a minute
No install, no config files, no YAML. Describe the endpoint in the browser and it is live.
Create an endpoint
Pick a path and an HTTP method. Dynamic segments like /users/:id work out of the box.
GET /users/:idPOST /ordersPUT /users/:idWrite the response
JSON, XML or a file. Add Faker placeholders, several responses per endpoint and rules that pick one.
{ "id": {{:id}}, "name": "{{faker.person.fullName()}}"}Call your URL
A real HTTPS endpoint answers immediately. Point your app at it, then swap the base URL when the backend ships.
$ curl https://api.mockfly.dev/mocks/acme/users/1200 OK · 12 msPowerful Mock API Features for Developers
Everything you need to fake a backend convincingly — and share it with the people who build against it.
Built for the way teams actually ship
Collaboration, realistic data, history and observability — the things you miss the moment a mock is more than a JSON file.
Real-Time Team Collaboration
Invite team members and work together seamlessly. Share endpoints, sync changes instantly, and accelerate your development workflow.
Realistic Data with Faker.js
Generate authentic-looking names, emails, addresses, phone numbers, and more. Make your test data indistinguishable from production.
AI-Powered Response Generation
Describe what you need in plain English. Our AI creates complete JSON responses and endpoint descriptions automatically.
Version History & Diff View
Track every change made to your endpoints. Visualize differences between versions and rollback when needed.
Request Logging & Debugging
Monitor every request hitting your endpoints. Inspect headers, bodies, and timing for easy debugging.
Visual Usage Analytics
Understand your API usage patterns with interactive charts. Identify trends and optimize your endpoints.
Comprehensive Analytics Dashboard
See endpoint counts, response statistics, and most-called endpoints at a glance. Complete visibility into your API project.
Who Uses Mock APIs? Developers Trust Mockfly
Developers and teams across industries use mock APIs to accelerate development, enable parallel workflows, and improve API testing.
Frontend Developers
Build and test UI components without waiting for backend APIs. Use mock APIs to develop features in parallel with backend teams. Create mock REST endpoints instantly and iterate faster on user interfaces with realistic fake data.
Backend Developers
Test service integrations and API contracts before implementation. Use mock APIs to simulate third-party services and external dependencies. Create mock endpoints for any API you depend on during development.
Mobile App Developers
Develop iOS and Android apps independently from backend availability. Mock APIs let you test offline scenarios, various response states, and error handling. Build your mobile app faster with free mock API endpoints.
QA & Testing Engineers
Create consistent test environments with predictable mock API responses. Simulate edge cases, errors, and timeout scenarios for thorough API testing. Use mock endpoints to ensure comprehensive test coverage.
Teams ship faster with Mockfly
Engineers at banks, retailers and startups use Mockfly so frontend and backend never wait for each other.
Using Mockfly as a mock API has helped us speed up development and test all types of scenarios. It's super useful and has good UX.
Iván Zamarro
Software Architect · Inditex
Its intuitive interface, the ease with which you can create endpoints, and its ability to generate random data make it one of the best tools for API mocking.
Adrián Fuentes
SecDevOps · BBVA
It's a vital tool in our developments because it allows our back-end and front-end teams to work independently of each other. If you want to mock an API, it's perfect.
Miguel Carvajal
Frontend Engineer · Reveni
Mockfly is a tool for creating mock APIs and serving REST requests. It has a very intuitive interface and useful features such as auto-documentation.
Sebastián Trinidad
Backend Engineer · BBVA Next Technologies
If you're seeking a tool to mock your API professionally, yet easily, with a pleasant interface, this is the perfect choice. They offer excellent support, and we selected it for its outstanding UX.
Gianmarco Segura
Fullstack Engineer · La Liga
Run your mock APIs offline
Pull your Mockfly projects once while you're online, then serve them locally with no internet — on a plane, in a CI pipeline, or on the train. Same conditional rules, Faker templating and placeholders as production.
- Works fully offline after a single pull
- Identical response engine to the cloud
- One npm install, zero config
# 1. while you're online
$ npx mockfly-cli login
$ npx mockfly-cli pull
# 2. now go offline — keep mocking
$ npx mockfly-cli serve
✓ Mockfly serving on http://localhost:4000Mock API FAQ - Common Questions About API Mocking
Ship the frontend before the backend exists.
Create a project, add an endpoint and call it — the free plan needs no credit card.