OpenAPI Plugin

Compile-time OpenAPI integration for Javalin 7.x ecosystem. This is a new plugin that replaces old built-in OpenApi module, the API looks quite the same despite some minor changes.

How to use

See https://javalin.github.io/javalin-openapi.

Notes

• Reflection free
• Uses @OpenApi to simplify migration from bundled OpenApi implementation
• Supports Java 17+ and Kotlin (through Kapt)
• Uses internal WebJar handler that works with /* route out of the box
• Provides better projection of OpenAPI specification
• Schema validation through Swagger core module

Other examples

• Test module - JavalinTest shows how this plugin work in Java codebase using various features
• Reposilite - real world app using Javalin and OpenApi integration

Repository structure

Universal modules

Module	Description
openapi-annotation-processor	Compile-time annotation processor, should generate /openapi-plugin/openapi-{default/<version>}.json resources
openapi-generator	Shared schema generation logic: type mappings, runtime builder DSL, example generation
openapi-specification	Annotations & classes used to describe OpenAPI specification
examples	Example Javalin application that uses OpenApi plugin in Gradle & Maven

Javalin plugins

Plugin	Description
javalin-openapi-plugin	Loads /openapi-plugin/openapi-{default/<version>}.json resources and serves main OpenApi endpoint
javalin-swagger-plugin	Serves Swagger UI
javalin-redoc-plugin	Serves ReDoc UI

Branches

Branch	Javalin version	OpenApi Version	Java Version
main	7.x	7.x	JDK17
6.x	6.x	6.x	JDK11
5.x	5.x	5.x	JDK11
4.x	4.x	1.x	JDK8