head to head · open source
Insomnia vs openapi-generator
Insomnia has 40,109 GitHub stars, 2,387 forks, 874 open issues and last shipped yesterday. openapi-generator has 26,844 stars, 7,746 forks, 5,819 open issues and last shipped yesterday. Insomnia leads on adoption by 49% (40,109 vs 26,844 stars). Insomnia is written in TypeScript under Apache-2.0; openapi-generator is written in Java under Apache-2.0. Insomnia has attracted 6% 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 3 topic tags (api, api-client, rest-api), 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.
← all 20902 open source comparisons
Side by side
| Insomnia | openapi-generator | |
|---|---|---|
| GitHub stars | ★ 40K | ★ 27K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | TypeScript | Java |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 2.4K | ⑂ 7.7K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Insomnia if
- You weight community size — 40K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches TypeScript
- 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 Insomnia
Insomnia API Client Insomnia is an open source, cross platform API client for GraphQL, REST, WebSockets, Server Sent Events (SSE), gRPC and any other HTTP compatible protocol. With Insomnia you can: Debug APIs using the most popular protocols and formats. Design APIs using the native OpenAPI editor and visual preview. Test APIs using native test suites and collection runner. Mock APIs using a cloud or self hosted mocking server. Build CI/CD pipelines using the native Insomnia CLI for linting and testing. Collaborate with others using the many collaboration features. And more including the ability to use 3rd…
read the full Insomnia overview →
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 →
More in Developer Tools
Related comparisons
More API Development & Testing projects
Compare either of these against the rest of the API Development & Testing field.
Frequently asked questions
Is Insomnia or openapi-generator more popular?
Insomnia has 40,109 GitHub stars and openapi-generator has 26,844. Insomnia has the larger community by that measure.
Are Insomnia and openapi-generator free?
Both are open source. Insomnia is licensed under Apache-2.0 and openapi-generator under Apache-2.0. Neither carries a licence fee.
What is the difference between Insomnia and openapi-generator?
Insomnia is written in TypeScript 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, Insomnia or openapi-generator?
Choose Insomnia if you want the larger community (40,109 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.