> For the complete documentation index, see [llms.txt](https://docs.mattermix.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mattermix.com/api/authentication.md).
# Authentication
The Mattermix API is expecting an [Authorization](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Authorization) header using the Bearer authentication scheme followed by your API key as the authorization parameter. For example, an authorization header would look like the following (replacing `Your-API-Key` with your actual API key): `Authorization: 'Bearer Your-API-Key'`.
Below is an example using the Fetch API from JavaScript:
```javascript
const body = {
html: "Hello World!
"
}
const res = await fetch("mattermix.com/api/v1/image", {
method: "POST",
headers: {
"Content-Type": "application/json",
Authorization: `Bearer ${process.env.MATTERMIX_API_KEY}`
},
body: JSON.stringify(body)
});
```
In the above example, the Mattermix API key is stored in an [environment variable](https://www.freecodecamp.org/news/what-are-environment-variables-and-how-can-i-use-them-with-gatsby-and-netlify/) named `MATTERMIX_API_KEY` to prevent the API key being exposed in committed code.
---
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