# Allowed HTML for Articles To provide the most flexibility possible, when [creating or updating an article](https://developers.intercom.com/docs/references/rest-api/api.intercom.io/Articles/createArticle/) you can use HTML and CSS to construct the article body. Whilst we allow a wide range of tags, we do not allow all of them. This is to ensure that we can render the article in all of our supported channels. You can find a list of supported tags below. Over time we may add support for new HTML elements and attributes. This will not constitute a breaking change, we advise any client code to support the full HTML specification when reading article content. Removing element support, or otherwise changing the API in a way that causes previously supported HTML to become unsupported will be considered a breaking change. ## Supported HTML | Tag | What does it do? | Additional Details | | --- | --- | --- | | `

` | Paragraph | All text must be placed within paragraph tags. | | `
` | Line break | Supported in-line. | | `

` | Horizontal rule | NA | | `

` `

` | Heading | Only these two header tags are supported. All others will be replaced with `

`. | | `` | Link | An image can be placed in-between the link tags. | | `` | Image | Images will be uploaded to Intercom and we'll use an Intercom link to display these.If these fail to upload then we'll hard fail and return `400 Bad Request`. | | `
` `
` `
` | List | Lists must contain at least one non-empty `
` element.`
` elements can contain plain text, or any other supported HTML tags, except ``.If these criteria aren't met, then the article will hard fail and return `400 Bad request`. | | `
` | Table | Needs to have at least one row and one cell.Can contain any other supported HTML tags, except another `
` within.If these criteria aren't met then it will hard fail and return `400 Bad request`. | | `` | Video | `src` must be for a supported video embed link.Only works for Youtube, Wistia, Vimeo, Loom, Vidyard or StreamIO. | | `<pre>` `<code>` | Pre-formatted code | | | `<b>` `<strong>` | Bold | | | `<i>` `<em>` | Italic | | ## Supported CSS | Class | What does it do? | Where does it work? | | --- | --- | --- | | `intercom-align-center` | Center Alignment | On tag level: Headers, Paragraphs.On wrapping div: Images, Buttons. | | `intercom-h2b-button` | Button | On tag level: Links | ## Unsupported HTML | Tag | What does it do? | What do we do? | | --- | --- | --- | | `<dl>` | Definition List | Hard fail - `400 Bad Request` | | `<ul>` or `<ol>` | Nested lists | Hard fail - `400 Bad Request` | | `<iframe>` | iFrameUnsupported video | Hard fail - `400 Bad Request` | | `<div>` `<span>` | Content division | Replace with `<p>` | | `<h3>` to `<h6>` | Heading | Replace with `<h2>` | | `<form>` | Form | Remove from content | | `<input>` `<textarea>` | Input | Remove from content | | `<script>` | Javascript Script | Remove from content | | `<head>` `<html>` `<footer>` etc. | All other tags | Remove from contentInternals replaced with `<p>` |