> For the complete documentation index, see [llms.txt](https://docs.tonic.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tonic.ai/textual/tonic-textual-api/textual-rest-api/rest-api-authentication.md).

# REST API authentication

Before you can use the Tonic Textual REST API, you must create a Textual API key. For information on how to obtain a Textual API key, go to [Creating and revoking Textual API keys](/textual/tonic-textual-api/textual-api-keys.md).

When you call the API, you place your API key in the authorization header of the request, similar to the following curl request, which fetches the list of datasets for the current user.

```sql
curl --request GET \
--url "https://textual.tonic.ai/api/dataset" \
--header "Content-Type: application/json" \
--header "Authorization: API_KEY"
```

Most Textual API requests require authentication. For each request, the reference information indicates whether the request requires an API key.

For requests that require an API key, if you do not provide a valid API key, you receive a `401 Unauthorized` response.


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