# OpenAPI

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.

GitBook supports [Swagger 2.0](https://github.com/OAI/OpenAPI-Specification/blob/main/versions/2.0.md) or [OpenAPI 3.0](https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.3.md) compliant files.

{% 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>


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# Agent Instructions: Querying This Documentation

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

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://gitbook.com/docs/api-references/openapi.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.