// the find
OpenAPITools/openapi-generator
OpenAPI Generator allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec (v2, v3)
A Java-based code generator that turns an OpenAPI/Swagger spec into client SDKs, server stubs, and docs across 50+ languages and frameworks. It's aimed at teams who own an API spec and don't want to hand-write or maintain client libraries for every language their consumers use.
The generator coverage is genuinely enormous and most popular targets (TypeScript/Axios, Java/Retrofit, C#/RestSharp, Python/FastAPI) are actively maintained with real CI matrices running generated samples against real frameworks, not just templates that compile. The Mustache template system means you can override generation per-language without forking the project. It's been running in production at a lot of companies for years, so the edge cases in OpenAPI 3.0/3.1 parsing (oneOf, discriminators, nullable types) are mostly ironed out already.
Generated code quality varies wildly by target language depending on how actively maintained that specific generator is — some of the 50+ options are near-abandoned and will produce code you wouldn't want to ship. The README's own security warning is worth taking seriously: feeding it a spec or template from an untrusted source can lead to code injection, so don't point this at specs you don't control. It's a Java/Maven-based CLI, which is an awkward dependency to add to a pure Python or Node pipeline just to generate a client. Customizing templates beyond basic overrides means learning Mustache plus the generator's Java model classes, which has a real learning curve.