Whether you're building a frontend app and the backend isn't ready yet, testing edge cases in your mobile app, or onboarding a new teammate who needs a safe sandbox — a mock API is the fastest solution.
This guide shows you how to create a mock API for testing using MockHub, a free online mock API generator. No terminal, no code, no configuration files.
Table of Contents
What is a Mock API?
A mock API is a fake API endpoint that returns pre-defined responses, simulating the behavior of a real backend. It lets developers and QA engineers work independently without waiting for the real service to be ready.
A mock REST API is useful when you need to:
- Develop a frontend before the backend is built
- Write automated tests that don't depend on external services
- Test error handling (400, 500, timeouts) in a controlled way
- Demo a product without live infrastructure
- Prototype an API contract before writing real code
Why Use MockHub as Your Mock API Generator
MockHub is an online mock API generator built for developers who want speed. No installation, no CLI, no YAML files. You fill in a form and get a live URL in seconds.
| Feature | MockHub | Postman Mock | Mockoon |
|---|---|---|---|
| No install required | ✔ Online | ✔ Online | ✘ Desktop app |
| Free tier | ✔ 5 APIs free | ✘ Limited | ✔ Open source |
| SOAP mock support | ✔ | ✘ | ✘ |
| AI-generated responses | ✔ | ✘ | ✘ |
| Dynamic variables | ✔ 24+ variables | ✘ | ✔ |
| Error / delay simulation | ✔ Scenarios | ✔ | ✔ |
| OpenAPI import | ✔ Premium | ✔ | ✔ |
Step-by-Step: Create a Mock REST API in 60 Seconds
Create a free account
Go to mockhub.ovh/api-generator/register.html and sign up with your email. No credit card required. The free plan gives you 5 mock API endpoints instantly.
Open the Mock API Generator
From your dashboard, click "Generate REST Mock" or go directly to mockhub.ovh/api-generator/generate_api.html.
Name your endpoint
Enter a path prefix for your endpoint, for example users or products-api. MockHub will generate a unique URL like:
Select HTTP methods
Choose which HTTP methods the endpoint should accept: GET, POST, PUT, DELETE, or any combination. MockHub rejects requests using unlisted methods with a clear error response.
Define the JSON response body
Paste the JSON you want the endpoint to return. This is the response your app or test will receive every time it calls the endpoint.
Click "Create" — your mock API is live
Hit the Create button. MockHub generates a live URL immediately. You can call it from your app, Postman, curl, or any HTTP client right away.
The endpoint stays active for 10 days and auto-renews every time it receives a request.
Use Dynamic Variables for Realistic Data
Static JSON returns the same values on every request. MockHub supports 24+ dynamic variables that generate fresh random values on each call. Just use the {{variableName}} syntax inside your JSON.
| Variable | Example output |
|---|---|
{{uuid}} | 550e8400-e29b-41d4-a716-446655440000 |
{{email}} | john.doe@example.com |
{{firstName}} | Alice |
{{timestamp}} | 2026-03-24T10:00:00Z |
{{randomNumber}} | 4821 |
{{IBAN}} | GB29NWBK60161331926819 |
{{IPv4}} | 192.168.1.42 |
Example — a dynamic user profile response:
Simulate Errors and Delays with Scenarios
Real APIs fail. Your app should handle errors gracefully. MockHub's Scenarios feature lets you switch your endpoint between different response profiles with one click — no code changes needed.
Each scenario can define:
- Status code — 200, 201, 400, 401, 403, 404, 500, 503…
- Response body — custom JSON for that state
- Delay — simulate slow APIs (0 to 60,000 ms)
- Error rate — random failure probability (0% to 100%)
Example scenarios for a /payment endpoint:
Common Use Cases for Mock REST APIs
Frontend development without a backend
Your backend team is still building the API. Create a mock REST API with the agreed contract, point your frontend at MockHub, and ship features without waiting.
Automated testing and CI/CD pipelines
Use a MockHub endpoint in your Jest, Cypress, or Playwright tests. Since the response is deterministic, your tests are reliable and don't depend on external services being available.
Testing error handling
Switch to a 500-error scenario and run your test suite to verify your app shows the right error messages, retries correctly, and doesn't crash.
API prototyping and client demos
Before writing a single line of backend code, generate a mock API and share the URL with stakeholders. Get feedback on the contract early.
Mobile app development
iOS and Android developers can hit a live MockHub endpoint from day one, with realistic dynamic data, without any backend infrastructure.
FAQ
Is MockHub free?
Yes. The free plan gives you 5 mock API endpoints with 40 calls/day each — enough for most testing needs. The premium plan unlocks 100 endpoints, 15,000 calls/day, AI generation, SOAP mocking, and OpenAPI import.
Do I need to install anything?
No. MockHub is fully online at mockhub.ovh. Open your browser and start creating.
How long does a mock endpoint stay active?
Endpoints are valid for 10 days and auto-renew every time they receive a request. Inactive endpoints expire automatically.
Can I use MockHub in CI/CD?
Yes. The endpoint URL is stable as long as the endpoint is active. You can hardcode it in your test config or environment variables.
Does MockHub support SOAP?
Yes. Upload a WSDL file and MockHub generates a fully working SOAP mock service with all operations. Available on the premium plan.
Can I import an OpenAPI / Swagger spec?
Yes. MockHub can parse an OpenAPI 3.x or Swagger 2.0 spec and create all endpoints automatically — available on the premium plan.
Create Your First Mock API Now
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