head to head · open source
openapi-generator vs NSwag
openapi-generator has 26,748 GitHub stars, 7,675 forks, 5,751 open issues and last shipped yesterday. NSwag has 7,365 stars, 1,360 forks, 2,057 open issues and last shipped 11 days ago. openapi-generator leads on adoption by 263% (26,748 vs 7,365 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 | 2026-09-17 | 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 is an Apache 2.0 licensed Java tool that generates API client libraries, server stubs, documentation, and configuration automatically from an OpenAPI Specification, and it is built for development teams that keep a machine readable API description and want generated code to stay in step with it.
read the full openapi-generator overview →
About NSwag
NSwag is an MIT licensed Swagger/OpenAPI 2.0 and 3.0 toolchain written in C for .NET, ASP.NET Core, and TypeScript developers who need to generate OpenAPI specifications from ASP.NET Web API controllers and generate C or TypeScript clients from those specifications.
read the full NSwag overview →
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Frequently asked questions
Is openapi-generator or NSwag more popular?
openapi-generator has 26,748 GitHub stars and NSwag has 7,365. 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 (26,748 stars) or its Apache-2.0 licence terms. Choose NSwag if its feature set, stack or MIT licence fits better. Both are self-hostable.