head to head · open source
OpenAPI-Specification vs Yaak
OpenAPI-Specification has 31,215 GitHub stars, 9,156 forks, 80 open issues and last shipped 7 days ago. Yaak has 19,224 stars, 813 forks, 19 open issues and last shipped yesterday. OpenAPI-Specification leads on adoption by 62% (31,215 vs 19,224 stars). OpenAPI-Specification is written in Markdown under Apache-2.0; Yaak is written in TypeScript under MIT. OpenAPI-Specification has attracted 29% as many forks as stars, Yaak 4%. Yaak 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
| OpenAPI-Specification | Yaak | |
|---|---|---|
| GitHub stars | ★ 31K | ★ 19K |
| License | Apache-2.0 | MIT |
| Written in | Markdown | TypeScript |
| Last push | 2026-09-11 | 2026-09-17 |
| Forks | ⑂ 9.2K | ⑂ 813 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick OpenAPI-Specification if
- You weight community size — 31K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Markdown
- You value the larger contributor base for long-term maintenance
pick Yaak if
- You want the Yaak feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches TypeScript
- You evaluated both and Yaak fits your workflow better
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 →
About Yaak
Yaak is a desktop API client for REST, GraphQL, gRPC, WebSocket, and Server Sent Events. It is built with Tauri, Rust, and React, and it lives in the developer tools ecosystem for API development and testing. The project presents itself as an offline first, privacy first alternative to Postman, Insomnia, and Bruno.
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Frequently asked questions
Is OpenAPI-Specification or Yaak more popular?
OpenAPI-Specification has 31,215 GitHub stars and Yaak has 19,224. OpenAPI-Specification has the larger community by that measure.
Are OpenAPI-Specification and Yaak free?
Both are open source. OpenAPI-Specification is licensed under Apache-2.0 and Yaak under MIT. Neither carries a licence fee.
What is the difference between OpenAPI-Specification and Yaak?
OpenAPI-Specification is written in Markdown and Yaak in TypeScript. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, OpenAPI-Specification or Yaak?
Choose OpenAPI-Specification if you want the larger community (31,215 stars) or its Apache-2.0 licence terms. Choose Yaak if its feature set, stack or MIT licence fits better. Both are self-hostable.