head to head · open source
openapi-generator vs NSwag
openapi-generator has 26,846 GitHub stars, 7,748 forks, 5,819 open issues and last shipped yesterday. NSwag has 7,369 stars, 1,363 forks, 2,057 open issues and last shipped 2 months ago. openapi-generator leads on adoption by 264% (26,846 vs 7,369 stars). openapi-generator is written in Java under Apache-2.0; NSwag is written in C# under MIT. openapi-generator has attracted 29% as many forks as stars, NSwag 18%. openapi-generator was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (openapi), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| openapi-generator | NSwag | |
|---|---|---|
| GitHub stars | ★ 27K | ★ 7.4K |
| License | Apache-2.0 | MIT |
| Written in | Java | C# |
| Last push | 2026-11-02 | 2026-09-07 |
| Forks | ⑂ 7.7K | ⑂ 1.4K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick openapi-generator if
- You weight community size — 27K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Java
- You value the larger contributor base for long-term maintenance
pick NSwag if
- You want the NSwag feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches C#
- You evaluated both and NSwag fits your workflow better
About openapi-generator
OpenAPI Generator Master ( 7.27.0 ): :star::star::star: If you would like to contribute, please refer to guidelines and a list of open tasks. :star::star::star: :bangbang: To migrate from Swagger Codegen to OpenAPI Generator, please refer to the migration guide :bangbang: :notebook with decorative cover: For more information, please refer to the Wiki page and FAQ :notebook with decorative cover: :notebook with decorative cover: The eBook A Beginner's Guide to Code Generation for REST APIs is a good starting point for beginners :notebook with decorative cover: :warning: If the OpenAPI spec, templates or any input…
read the full openapi-generator overview →
About NSwag
NSwag: The Swagger/OpenAPI toolchain for .NET, ASP.NET Core and TypeScript NSwag NJsonSchema Apimundo Namotion.Reflection :point right: Announcing Apimundo: An API documentation system based on NSwag and NJsonSchema :point left: NSwag is a Swagger/OpenAPI 2.0 and 3.0 toolchain for .NET, .NET Core, Web API, ASP.NET Core, TypeScript (jQuery, AngularJS, Angular 2+, Aurelia, KnockoutJS and more) and other platforms, written in C . The OpenAPI/Swagger specification uses JSON and JSON Schema to describe a RESTful web API. The NSwag project provides tools to generate OpenAPI specifications from existing ASP.NET Web API…
read the full NSwag overview →
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Frequently asked questions
Is openapi-generator or NSwag more popular?
openapi-generator has 26,846 GitHub stars and NSwag has 7,369. openapi-generator has the larger community by that measure.
Are openapi-generator and NSwag free?
Both are open source. openapi-generator is licensed under Apache-2.0 and NSwag under MIT. Neither carries a licence fee.
What is the difference between openapi-generator and NSwag?
openapi-generator is written in Java and NSwag in C#. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, openapi-generator or NSwag?
Choose openapi-generator if you want the larger community (26,846 stars) or its Apache-2.0 licence terms. Choose NSwag if its feature set, stack or MIT licence fits better. Both are self-hostable.