OpenAPI vs Swagger Codegen: What are the differences?

Key Differences between OpenAPI and Swagger Codegen 1. Definition: OpenAPI is a specification for designing, building, and documenting RESTful APIs, while Swagger Codegen is a tool that generates client libraries, server stubs, and API documentation from an OpenAPI specification. 2. Functionality: OpenAPI focuses on the design and documentation aspects of an API, providing a standard way to describe the API's endpoints, parameters, request/response schemas, and authentication requirements. In contrast, Swagger Codegen specifically focuses on code generation, allowing developers to generate client-side code (e.g., SDKs, API clients) or server-side code (e.g., server stubs) based on an OpenAPI specification. 3. Customizability: OpenAPI allows a high level of customization by supporting extensions, allowing developers to add custom fields, annotations, and details to their API specification. On the other hand, Swagger Codegen provides limited customization options, primarily allowing customization of the generated code templates and configuration settings. 4. Language Support: OpenAPI is language-agnostic and can be used to describe APIs in any programming language. Swagger Codegen, however, provides language-specific code generation for a wide range of programming languages, such as Java, Python, JavaScript, etc. 5. Generated Code Quality: OpenAPI does not directly generate code; therefore, the generated code quality depends on the tools or libraries used for code generation. Swagger Codegen, being a code generation tool, aims to generate idiomatic and high-quality code, following the best practices of the target programming language. 6. Maintenance: OpenAPI is a continuously evolving specification, with regular updates and improvements driven by the Open API Initiative. Swagger Codegen, though not actively developed or maintained by the Swagger team anymore, still has an active community and provides community-contributed plugins and updates.

In Summary, OpenAPI is a specification for designing RESTful APIs, while Swagger Codegen is a code generation tool that can generate client libraries, server stubs, and API documentation based on an OpenAPI specification. OpenAPI is more focused on API design and documentation, allowing customization and language-agnostic support, while Swagger Codegen provides specific code generation functionality for multiple programming languages.