# Template syntax The Mattermix API uses the [Handlebars](https://handlebarsjs.com/guide/) templating syntax to dynamically update values in HTML or CSS. For example, you could have the following in your HTML: `

{{title}}

`. The title value could be updated with the API by passing a title value in the `content` object of the request body. Below is an example using the Fetch API from JavaScript: ```javascript const body = { html: "

{{title}}

", content: { title: "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) }); ```