Express OpenAPI Framework

express-openapi is an unopinionated framework designed to integrate OpenAPI (formerly Swagger) specifications into Express.js applications. It currently supports OpenAPI versions 2.0 and 3.0. The library prioritizes performance and extensive testing, aiming to keep development as close to native Express patterns as possible while providing robust API documentation and validation capabilities. It achieves its features, such as parameter defaults, type coercion, request/response validation, and security handling, by leveraging a suite of modular `openapi-*` packages. The current stable version is 12.1.3. While not explicitly stating a release cadence, its version history suggests active development. Key differentiators include its flexible, unobtrusive design, comprehensive middleware configuration via vendor extensions, and the ability to maintain API documentation in sync with application code.