> For the complete documentation index, see [llms.txt](https://gitbook.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gitbook.com/docs/create-content/openapi.md).

# Document an API

Add an OpenAPI spec to a page and let your users test endpoints right on the page with interactive blocks.

Manually writing REST API documentation can be a time-consuming process. Fortunately, GitBook streamlines this task by allowing you to import OpenAPI documents, which detail your API’s structure and functionality.

The OpenAPI Specification (OAS) is a framework that developers use to document REST APIs. Written in JSON or YAML, it outlines all your endpoints, parameters, schemas, and authentication schemes.

Once imported into GitBook, these documents are transformed into interactive and testable API blocks that visually represent your API methods—whether the specification is provided as a file or loaded from a URL.

### OpenAPI compatibility

GitBook supports importing and rendering these specification versions:

* [Swagger 2.0](https://github.com/OAI/OpenAPI-Specification/blob/main/versions/2.0.md) — supported.
* [OpenAPI 3.0](https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.3.md) — supported.
* [OpenAPI 3.1](https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.1.1.md) — supported, including OpenAPI 3.1-only features such as `webhooks`.

{% openapi src="<https://petstore3.swagger.io/api/v3/openapi.json>" path="/pet" method="post" %}
<https://petstore3.swagger.io/api/v3/openapi.json>
{% endopenapi %}

### Test it (powered by Scalar)

GitBook's OpenAPI block also supports a "test it" functionality, which allows your users to test your API methods with data and parameters filled in from the editor.

Powered by [Scalar](https://scalar.com/), you won't need to leave the docs to see your API methods in action. See an example of this above.

#### FAQ

<details>

<summary>Why isn’t my spec loading?</summary>

{% hint style="info" %}
**Note:** This information only applies to **specs added by URL**.
{% endhint %}

If you added your specification via URL, your API must [allow cross-origin](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Access-Control-Allow-Origin) GET requests from your docs site. In your API’s CORS settings, allow the exact origin where your docs are hosted (e.g., `https://your-site.gitbook.io` or `https://docs.example.com`).\
\
If your endpoint is public and doesn’t use credentials, you can also return: `Access-Control-Allow-Origin: *`\ <br>

</details>


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://gitbook.com/docs/create-content/openapi.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

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