Mock API Server

Design Mock APIs in Seconds

Create realistic API endpoints with custom responses, status codes, and delays. Perfect for frontend development, demos, and integration testing.

Note

This tool helps you design and document mock APIs. To expose them on the internet you can copy the generated configuration into tools like json-server, Express, or online mock API platforms.

No endpoints defined yet. Click Add to create your first mock API route.
Overview

Design and Simulate REST API Endpoints Entirely in the Browser

The Mock API Server lets you design realistic HTTP endpoints with custom methods, paths, status codes, response bodies, and simulated latency — all running locally without deploying a single line of server code. Pre-built categories cover common patterns: authentication, e-commerce, payments, email, and analytics, each loaded with sensible default routes you can use immediately or modify.

Once you have your endpoints configured, test them with one click, preview the generated cURL command, export the full configuration as JSON for reuse, or download an OpenAPI 3.0 specification to share with your team or import into tools like Postman.

100% freeNo sign-upNo backend neededOpenAPI export
How to use it
  1. 1Select a route from the sidebar (grouped by category) or click Add to create a blank endpoint from scratch.
  2. 2Set the HTTP method, path, status code, simulated delay in milliseconds, and Content-Type for the selected route.
  3. 3Edit the JSON response body directly in the editor; use double-brace templates like {{API_BASE_URL}} to inject environment variables or {{random:email}} to insert generated data.
  4. 4Click Test Endpoint to simulate the response with the configured delay and review the simulated output alongside the generated cURL example.
  5. 5Export the full configuration as JSON to restore it later, or export an OpenAPI spec to document your mock API for teammates.
Key features
  • Five built-in category groups (Authentication, E-commerce, Payments, Email, Analytics) with pre-populated default routes.
  • Per-route rate limiting with configurable request count and time window, simulated entirely in-browser.
  • Environment variable substitution in response bodies using double-brace syntax, so responses can reference shared values like base URLs or secrets.
  • Random data generators in response templates: id, uuid, name, email, timestamp, boolean, number, and status.
  • One-click OpenAPI 3.0 spec export that groups your enabled routes by path and method with example response schemas.
  • Request log panel tracking method, path, simulated latency, and timestamp for the last 50 test calls.
  • Webhook event history showing the last 10 simulated webhook payloads generated from your endpoints.

Frequently asked questions

Does this actually expose my endpoints on the internet?
No. All simulation runs locally in your browser. The base URL field is for documentation purposes only. To serve these endpoints over the network you would copy the configuration into a tool like json-server or Express.
Can I save my endpoint configuration and reload it later?
Yes. Use Export Config to download a JSON file containing all your routes and environment variables, then Import Config to restore them in a future session.
What are environment variables used for?
They let you define shared values (like API base URLs or placeholder secrets) once and reference them in any response body using {{VARIABLE_NAME}} syntax, making it easy to update a value across all routes at once.
Can I add my own route categories?
You can assign any route to an existing category via the category selector. Custom category IDs typed directly will appear as new groups in the sidebar.
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Full guide

Mock API Server Complete Guide

Create mock API endpoints, configure responses, and test frontend apps without a real backend.

Create mock API endpointsTest frontend without a backendCommon questions answered

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