head to head · open source
OpenAPI-Specification vs openapi-generator
OpenAPI-Specification has 31,291 GitHub stars, 9,145 forks, 80 open issues and last shipped 12 days ago. openapi-generator has 26,846 stars, 7,749 forks, 5,810 open issues and last shipped today. OpenAPI-Specification leads on adoption by 17% (31,291 vs 26,846 stars). OpenAPI-Specification is written in Markdown under Apache-2.0; openapi-generator is written in Java under Apache-2.0. OpenAPI-Specification has attracted 29% as many forks as stars, openapi-generator 29%. openapi-generator was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (openapi, rest), 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-Specification | openapi-generator | |
|---|---|---|
| GitHub stars | ★ 31K | ★ 27K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Markdown | Java |
| Last push | 2026-10-22 | 2026-11-03 |
| Forks | ⑂ 9.1K | ⑂ 7.7K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick OpenAPI-Specification if
- You weight community size — 31K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Markdown
- You value the larger contributor base for long-term maintenance
pick openapi-generator if
- You want the openapi-generator feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Java
- You evaluated both and openapi-generator fits your workflow better
About OpenAPI-Specification
The OpenAPI Specification The OpenAPI Specification is a community driven open specification within the OpenAPI Initiative, a Linux Foundation Collaborative Project. The OpenAPI Specification (OAS) defines a standard, programming language agnostic interface description for HTTP APIs. This allows both humans and computers to discover and understand the capabilities of a service without requiring access to source code, additional documentation, or inspection of network traffic. When properly defined via OpenAPI, a consumer can understand and interact with the remote service with a minimal amount of implementation…
read the full OpenAPI-Specification overview →
About openapi-generator
OpenAPI Generator Master ( 7.28.0 ): :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 →
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Frequently asked questions
Is OpenAPI-Specification or openapi-generator more popular?
OpenAPI-Specification has 31,291 GitHub stars and openapi-generator has 26,846. OpenAPI-Specification has the larger community by that measure.
Are OpenAPI-Specification and openapi-generator free?
Both are open source. OpenAPI-Specification is licensed under Apache-2.0 and openapi-generator under Apache-2.0. Neither carries a licence fee.
What is the difference between OpenAPI-Specification and openapi-generator?
OpenAPI-Specification is written in Markdown and openapi-generator in Java. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, OpenAPI-Specification or openapi-generator?
Choose OpenAPI-Specification if you want the larger community (31,291 stars) or its Apache-2.0 licence terms. Choose openapi-generator if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.