head to head · open source
Insomnia vs OpenAPI.NET
Insomnia has 40,022 GitHub stars, 2,367 forks, 874 open issues and last shipped yesterday. OpenAPI.NET has 1,610 stars, 286 forks, 31 open issues and last shipped 2 days ago. Insomnia leads on adoption by 2,386% (40,022 vs 1,610 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 | 2026-09-18 | 2026-09-17 |
| Forks | ⑂ 2.4K | ⑂ 286 |
| 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 is an open source, cross platform API client built with Electron and TypeScript for developing and testing APIs across multiple protocols including REST, GraphQL, WebSockets, SSE, and gRPC. It runs on macOS, Windows, and Linux and is distributed under the Apache 2.0 license. The project serves as a direct open source alternative to Postman, offering similar core functionality without vendor lock in or mandatory cloud usage.
read the full Insomnia overview →
About OpenAPI.NET
OpenAPI.NET is the Microsoft maintained .NET SDK that provides a shared object model for OpenAPI descriptions, together with readers and writers that convert OpenAPI JSON and YAML documents into and out of that model, and it is aimed at C and .NET developers who build, validate, or transform OpenAPI documents in code.
read the full OpenAPI.NET overview →
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Frequently asked questions
Is Insomnia or OpenAPI.NET more popular?
Insomnia has 40,022 GitHub stars and OpenAPI.NET has 1,610. 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 (40,022 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.