Self-hosted alternatives to openapi-spec-generation

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openapi-spec-generation

Generates OpenAPI 3.1 specs from code

Generate, maintain, and validate OpenAPI 3.1 specifications for RESTful APIs. Supports design-first, code-first, and hybrid approaches with templates for complete specs, FastAPI/Python generation, and TypeScript/Express decorators. Includes reusable components for schemas, parameters, responses, and security schemes to minimize duplication across endpoints.