swagger-api/swagger-ui

Swagger UI is a tool that automatically generates a visual, interactive web page for your API (Application Programming Interface, the way software programs talk to each other) from a description file. Instead of writing docs by hand, you define your API's endpoints, parameters, and responses in a standard format called OpenAPI (formerly Swagger), and Swagger UI reads that file and produces a polished, browsable documentation page. Visitors can see every available endpoint, understand what data to send, and even send real test requests directly from the browser, no code required. This matters for anyone building or using a web-based service. Backend developers use it to document their work, frontend developers use it to understand how to call the API, and non-technical stakeholders can browse what the API can do without reading raw code. QA testers can also trigger real API calls from the UI to verify behavior. The tool is distributed as a set of HTML, JavaScript, and CSS files. You can drop the files directly onto any web server, include it as an npm package for JavaScript projects, or use a Docker image if you prefer containerized deployments. It supports the OpenAPI specification across multiple versions (2.0 through 3.x), so it works with most modern API description files. The project is open-source, written in JavaScript, and available under standard licensing.