Mock APIs, webhooks and WebSockets — in seconds
Free developer tools — mock APIs, webhook tester, WebSocket tester, JSON formatter and more
- ✓ Free mock REST & WebSocket APIs
- ✓ AI-generated test data
- ✓ MCP server for AI agents
MockFox gives you a working backend before the real one exists: a hosted mock REST API, an AI generator that writes it for you, a webhook catcher and a WebSocket test server — plus the everyday utilities you reach for while debugging.
Mock servers
- Mock APIHost a fake REST API from JSON in seconds. CRUD, filters, pagination, custom routes.
- AI mock API generatorDescribe your API in plain English; get endpoints and realistic data.
- Webhook testerA URL that captures every request so you can inspect headers and payloads.
- WebSocket testerConnect to any ws:// or wss:// server, send messages, watch the log.
- Fake REST APIFree JSONPlaceholder-style endpoints: users, posts, todos, products, orders.
- WebSocket mock serverScripted wss:// endpoint: welcome messages, timed pushes, pattern replies.
Testing
JSON & data
Encoding & crypto
- JWT DecoderRead a JWT's header and claims, with expiry shown as a date.
- Base64 Encode & DecodeUTF-8 text to Base64 and back, URL-safe mode, files to data URIs.
- URL Encode & DecodePercent-encode or decode text and parse query strings into a table.
- Hash Generator (MD5, SHA-256 & more)MD5, SHA-1, SHA-256/384/512 and HMAC of text or files.
Generators
Built for developers and AI agents
Every mock gets a public HTTPS URL with CORS enabled, so you can call it from a browser app, a test suite or CI. MockFox also runs an MCP server, so Claude, Cursor and other agents can create and call mocks for you.