head to head · open source
Insomnia vs OpenAPI-Specification
Insomnia has 40,021 GitHub stars, 2,365 forks, 874 open issues and last shipped yesterday. OpenAPI-Specification has 31,215 stars, 9,156 forks, 80 open issues and last shipped 7 days ago. Insomnia leads on adoption by 28% (40,021 vs 31,215 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 | 2026-09-17 | 2026-09-11 |
| Forks | ⑂ 2.4K | ⑂ 9.2K |
| 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 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-Specification
The OpenAPI Specification (OAS) is a community driven open specification hosted within the OpenAPI Initiative, a Linux Foundation Collaborative Project. It defines a standard, programming language agnostic interface description for HTTP APIs, represented in YAML or JSON. The specification lives in the HTTP API tooling ecosystem, alongside the tools, libraries, and implementations listed in the repository's implementations document. The project source is released under the Apache 2.0 license, and its GitHub repository has accumulated roughly 31,000 stars and 9,100 forks across 13 years of activity.…
read the full OpenAPI-Specification overview →
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Frequently asked questions
Is Insomnia or OpenAPI-Specification more popular?
Insomnia has 40,021 GitHub stars and OpenAPI-Specification has 31,215. 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 (40,021 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.