Swagger Core is a Java implementation of the OpenAPI Specification that generates API documentation from your REST API code.
The tool solves the problem of keeping API documentation in sync with implementation by automatically generating OpenAPI specification documents from annotated Java code. It works by scanning JAX-RS2 endpoints and their annotations, extracting metadata about request and response structures, and producing machine-readable specifications that describe your REST API.
Developers should choose this tool if they are building REST APIs in Java using JAX-RS2 and want to maintain accurate, up-to-date API documentation without manual effort. It suits projects where the API contract needs to be discoverable by client developers and tooling. The tool supports both the javax and jakarta namespaces, allowing use in projects that have migrated to Jakarta EE. It also supports OpenAPI 3.1 in addition to earlier specification versions, giving teams flexibility in which OpenAPI version they target.
The project maintains active build and deployment workflows, with continuous integration testing across the codebase. Documentation is centralized in the project wiki, which contains getting started guides, samples, and contribution guidelines. The project acknowledges multiple specification versions and provides clear migration paths, including a separate branch for users who need the older 1.5.X line with OpenAPI 2.0 support.
