> For the complete documentation index, see [llms.txt](https://developers.slyk.io/slyk/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developers.slyk.io/slyk/reference/using-your-api-key.md).

# Using your API Key

All API calls are authorized using an API key, which should be provided via an `apiKey` header. For instance, in command line you could do:

`curl -H "apiKey: API_KEY"` [`https://api.slyk.io/users`](https://api.slyk.io/users)

Just replace API\_KEY with your own key.