head to head · open source
one-api vs OpenAPI-Specification
one-api has 36,932 GitHub stars, 6,867 forks, 1,036 open issues and last shipped 8 months ago. OpenAPI-Specification has 31,215 stars, 9,156 forks, 80 open issues and last shipped 7 days ago. one-api leads on adoption by 18% (36,932 vs 31,215 stars). one-api is written in JavaScript under MIT; OpenAPI-Specification is written in Markdown under Apache-2.0. one-api has attracted 19% as many forks as stars, OpenAPI-Specification 29%. OpenAPI-Specification 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
| one-api | OpenAPI-Specification | |
|---|---|---|
| GitHub stars | ★ 37K | ★ 31K |
| License | MIT | Apache-2.0 |
| Written in | JavaScript | Markdown |
| Last push | 2026-01-09 | 2026-09-11 |
| Forks | ⑂ 6.9K | ⑂ 9.2K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick one-api if
- You weight community size — 37K stars and counting
- You want the MIT license terms
- Your stack matches JavaScript
- 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 one-api
One API is a self hosted LLM API management and key redistribution system that exposes many model providers through the standard OpenAI API format, aimed at developers, teams and operators who want a single endpoint, a single key model and a single quota surface across providers.
read the full one-api 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 one-api or OpenAPI-Specification more popular?
one-api has 36,932 GitHub stars and OpenAPI-Specification has 31,215. one-api has the larger community by that measure.
Are one-api and OpenAPI-Specification free?
Both are open source. one-api is licensed under MIT and OpenAPI-Specification under Apache-2.0. Neither carries a licence fee.
What is the difference between one-api and OpenAPI-Specification?
one-api is written in JavaScript 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, one-api or OpenAPI-Specification?
Choose one-api if you want the larger community (36,932 stars) or its MIT licence terms. Choose OpenAPI-Specification if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.