JSONing

About JSONing

JSONing is an open-source mock API tool for testing and prototyping. It lets developers define a set of resources as a single JSON object, with each attribute representing a resource containing an array of elements, and automatically generates standard REST routes (GET, POST, PUT, PATCH, DELETE) for each resource. A rule engine allows custom conditions based on request method, headers, path, or payload, with matching rules able to override the response status, body, and headers - useful for simulating error cases such as HTTP 401 responses.

The tool can be run locally via source code downloaded from GitHub, or used online by defining resources and rules through editors on the site, which generates an API immediately accessible over HTTP; online APIs are deleted once a day and can be recreated as needed. A hosted read-only public API is also available at api.jsoning.com/mock/public/{resource}, offering fixed sample data for resources including products, carts, users, and coupons, plus a /status endpoint for simulating specific HTTP response codes.

The tool is intended for developers who need a quick fake backend for testing and prototyping without setting up their own server, and is free to use.

Key features

• Generates a custom REST API instantly from a JSON resource object
• Supports full CRUD routes (GET, POST, PUT, PATCH, DELETE) on resources
• Rule engine to customize HTTP status codes, headers, and response bodies per request
• Open-source and downloadable for local installation
• Includes a free public read-only API with sample products, carts, users, and coupons data
• Simulates HTTP status codes via /status/{code} endpoint

Frequently asked questions