head to head · open source
Insomnia vs OpenAPI-Specification
Insomnia has 40,111 GitHub stars, 2,388 forks, 874 open issues and last shipped yesterday. OpenAPI-Specification has 31,291 stars, 9,145 forks, 80 open issues and last shipped 12 days ago. Insomnia leads on adoption by 28% (40,111 vs 31,291 stars). Insomnia is written in TypeScript under Apache-2.0; OpenAPI-Specification is written in Markdown under Apache-2.0. Insomnia has attracted 6% as many forks as stars, OpenAPI-Specification 29%. 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-Specification | |
|---|---|---|
| GitHub stars | ★ 40K | ★ 31K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | TypeScript | Markdown |
| Last push | 2026-11-02 | 2026-10-22 |
| Forks | ⑂ 2.4K | ⑂ 9.1K |
| 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-Specification if
- You want the OpenAPI-Specification feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Markdown
- You evaluated both and OpenAPI-Specification 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-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 →
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Frequently asked questions
Is Insomnia or OpenAPI-Specification more popular?
Insomnia has 40,111 GitHub stars and OpenAPI-Specification has 31,291. Insomnia has the larger community by that measure.
Are Insomnia and OpenAPI-Specification free?
Both are open source. Insomnia is licensed under Apache-2.0 and OpenAPI-Specification under Apache-2.0. Neither carries a licence fee.
What is the difference between Insomnia and OpenAPI-Specification?
Insomnia is written in TypeScript and OpenAPI-Specification in Markdown. 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-Specification?
Choose Insomnia if you want the larger community (40,111 stars) or its Apache-2.0 licence terms. Choose OpenAPI-Specification if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.