Free Mock API Server — No Sign-Up Required

Free API
Mock Server

Drop your OpenAPI spec or Bruno collection and get a fully functional mock API server instantly. Export to Bruno API client or test directly — no account needed.

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How the API Mock Server works

Three steps to a working mock API

1. Paste your spec or upload Bruno

Upload or paste your OpenAPI/Swagger specification in JSON or YAML, or upload a Bruno collection (ZIP or JSON export).

2. Generate instantly

We parse your spec and create a live mock API with realistic responses.

3. Start testing

Use the mock URL in your frontend. Responses match your schema definitions.

Why use an API mock server?

Mock servers accelerate development by letting frontend and backend teams work in parallel.

Develop frontend without a backend

Don't wait for your backend team to finish building APIs. Generate a mock API server from your OpenAPI spec and start integrating your frontend immediately. The mock server returns realistic responses based on your schema definitions, examples, and data types.

Test API integrations safely

Run integration tests against a mock server instead of your production API. No risk of side effects, no rate limits to worry about, and consistent responses every time. Perfect for CI/CD pipelines and automated testing.

Frontend Development

Build UI components against realistic API responses before the real API exists.

API Prototyping

Validate your API design with stakeholders using a working mock before implementation.

Integration Testing

Run automated tests against consistent mock responses without external dependencies.

Built-in Bruno Export

Bruno API Client Mock Server Integration

Export your mock server as a Bruno collection with one click. Test every endpoint in Bruno instantly.

One-click export to Bruno

ApiNotes is the only mock server that exports directly to Bruno API client format. After generating your mock server, click “Export to Bruno” to download a complete Bruno collection with all endpoints pre-configured, including the mock server base URL, request headers, and example request bodies.

Why use Bruno for mock testing?

Bruno is an open-source, offline-first API client that stores collections in plain text files — perfect for version control. Unlike Postman, Bruno collections live in your Git repo. Combined with ApiNotes mock servers, you get a fully local, privacy-first testing workflow with no cloud lock-in.

Open Source & Offline

Bruno runs locally without cloud accounts. Your API collections are plain files stored alongside your code.

Git-Friendly Collections

Export mock endpoints as Bruno .bru files, commit them to your repo, and share with your entire team.

Postman Alternative

Bruno is a free, privacy-focused Postman alternative. ApiNotes + Bruno gives you mock testing without vendor lock-in.

Frequently asked questions