Quick Answer
A mock API server is a public URL that returns whatever response you configure — status code, headers, JSON body, even a delay. Requex.me hosts one for you free. No npm install, no Docker, no deploy. Useful when the real API is not ready, is rate-limited, or costs money per call.
Mock API Server — Free, Hosted, No Setup
Get a public HTTPS endpoint, write the response you want it to return, and start hitting it from your app or tests. No server to run, no library to install. Free forever for development use.
When you need a mock API server
A mock server pays for itself the first time you are blocked on a backend you can not change. Frontend ready before the API is built. Integration tests that you do not want to run against production. A flaky third-party API that you need to make behave for a demo. Rate-limited sandbox credits you do not want to burn through.
The honest version: most "mock server" tools want you to install something. Mockoon needs the desktop app. WireMock needs Java. json-server needs Node. Postman mock servers need a Postman account and live inside their UI. A hosted mock server skips all of that — you just get a URL.
How Requex's mock server works
Open the dashboard, copy a URL
Visit requex.me. A unique HTTPS endpoint is generated instantly. No signup until you want to persist endpoints across sessions.
Configure the response
Open Response Settings. Set status code (200, 201, 400, 401, 422, 500 — any). Paste the JSON body you want returned. Add response headers. Optionally add a delay (1s, 5s, 30s) to simulate a slow upstream.
Point your code at the URL
Use it the same way you would use the real API. Every request hits your mock, returns the configured response, and is logged so you can verify what your client sent.
What you can mock
| Capability | How |
|---|---|
| Custom status codes | 200, 201, 400, 401, 403, 404, 422, 429, 500, 503 — any HTTP code |
| JSON / XML / text body | Paste exact response payload — no template engine to learn |
| Custom response headers | Set Content-Type, WWW-Authenticate, custom auth headers |
| Response delays | Simulate slow upstreams or test client-side timeouts |
| Echo / mirror modes | Return the request body back, or mirror selected fields |
| Template variables | {{body.x}}, {{query.x}}, {{headers.x}} |
| Auth simulation | Bearer / API key / Basic / HMAC / custom — return 401 for invalid credentials |
Hosted vs self-hosted mock servers
Self-hosted tools (Mockoon, WireMock, json-server) are great when you need offline development or compliance reasons forbid sending traffic outside your network. They are bad when you just need a quick URL — install, learn syntax, run a process, expose a port, share the URL with the team.
Hosted mock servers (Requex, Beeceptor, webhook.site Pro, Postman mock) skip the install and run step. The trade-off is that the response config lives somewhere you do not own. For dev and CI, that is fine. For production traffic, run your own.
Common questions
Is this a free mock API server?
Yes. Requex.me is free for development use — no signup required for short sessions, free account for persistent endpoints. No paid tier required to set status codes, custom JSON, headers, or delays.
Can I use this in CI / automated tests?
Yes, the URL is stable for the session and stays available 24/7. For long-lived CI usage, create a free account so your mock endpoints persist across runs.
How is this different from a webhook tester?
Same plumbing, different intent. A webhook testing tool is built to inspect incoming requests. A mock API server is built to return a specific response your client expects. Requex.me does both — it is the same endpoint with response settings configured.
Can it return different responses for different requests?
Yes. Use template variables ({{body.userId}}, {{query.limit}}) to echo back parts of the request. See conditional mock responses for the full guide.
Can I import an OpenAPI / Swagger spec?
Not directly — Requex stays config-light by design. If you need spec-driven mocking, see the OpenAPI mock server guide for an approach that combines the two.
Related
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