head to head · open source
Insomnia vs OpenAPI.NET
Insomnia has 40,111 GitHub stars, 2,388 forks, 874 open issues and last shipped yesterday. OpenAPI.NET has 1,616 stars, 291 forks, 31 open issues and last shipped 6 days ago. Insomnia leads on adoption by 2,382% (40,111 vs 1,616 stars). Insomnia is written in TypeScript under Apache-2.0; OpenAPI.NET is written in C# under MIT. Insomnia has attracted 6% as many forks as stars, OpenAPI.NET 18%. Insomnia was the more recently maintained of the two, and both are self-hostable with no licence fee.
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
| Insomnia | OpenAPI.NET | |
|---|---|---|
| GitHub stars | ★ 40K | ★ 1.6K |
| License | Apache-2.0 | MIT |
| Written in | TypeScript | C# |
| Last push | 2026-11-02 | 2026-10-28 |
| Forks | ⑂ 2.4K | ⑂ 291 |
| 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.NET if
- You want the OpenAPI.NET feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches C#
- You evaluated both and OpenAPI.NET 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.NET
OpenAPI.NET The OpenAPI.NET SDK contains a useful object model for OpenAPI documents in .NET along with common serializers to extract raw OpenAPI JSON and YAML documents from the model. See more information on the OpenAPI specification and its history here: OpenAPI Initiative Project Objectives: Provide a single shared object model in .NET for OpenAPI descriptions. Include the most primitive Reader for ingesting OpenAPI JSON and YAML documents in both V2 and V3 formats. Provide OpenAPI description writers for both V2 and V3 specification formats. Enable developers to create Readers that translate different data…
read the full OpenAPI.NET overview →
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Frequently asked questions
Is Insomnia or OpenAPI.NET more popular?
Insomnia has 40,111 GitHub stars and OpenAPI.NET has 1,616. Insomnia has the larger community by that measure.
Are Insomnia and OpenAPI.NET free?
Both are open source. Insomnia is licensed under Apache-2.0 and OpenAPI.NET under MIT. Neither carries a licence fee.
What is the difference between Insomnia and OpenAPI.NET?
Insomnia is written in TypeScript and OpenAPI.NET 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, Insomnia or OpenAPI.NET?
Choose Insomnia if you want the larger community (40,111 stars) or its Apache-2.0 licence terms. Choose OpenAPI.NET if its feature set, stack or MIT licence fits better. Both are self-hostable.