# Rich text

> For the complete documentation index, see [llms.txt](https://docs.arcweave.com/llms.txt). All pages are also available in one file, [llms-full.txt](https://docs.arcweave.com/llms-full.txt).

Source: https://docs.arcweave.com/rest-api/rich-text
Section: REST API
Description: Supported HTML and validation rules for rich-text REST API fields

Rich-text fields in REST API requests accept HTML and use the same [field-specific formatting](https://docs.arcweave.com/project-tools/rich-text#supported-formatting) as the editor.

## Supported HTML

Context: Arcweave docs > REST API > Rich text > Supported HTML

Use `<p>` for paragraphs, `<br>` for line breaks, `<strong>` or `<b>` for bold, `<em>` or `<i>` for italic, `<u>` for underline, `<s>` for strikethrough, and `<a href="…">` for links.

`<del>` and `<strike>` are also accepted and stored as `<s>`. Fields without strikethrough reject `<s>`, `<del>`, and `<strike>`, as they reject `<u>`.

Use `<blockquote><p>…</p></blockquote>` only in element content or rich-text attributes. To add an Arcscript segment to element content or a connection label, use a complete `<pre><code>…</code></pre>` block. An inline `<code>…</code>` tag is rejected; code blocks are also rejected in titles, notes, and rich-text attributes.

## Example

Context: Arcweave docs > REST API > Rich text > Example

Send this body to [Update element](https://docs.arcweave.com/rest-api/elements#update-element) to update its title and content:

```json
{
  "title": "<p>A <strong>quiet</strong> room</p>",
  "content": "<p>You enter the room.</p><blockquote><p>Welcome.</p></blockquote><pre><code>show(\"Hello\")</code></pre>"
}
```

## Validation

Context: Arcweave docs > REST API > Rich text > Validation

Unsupported markup returns `400 Bad Request`. The API normalizes accepted HTML when saving it. See [Localized content](https://docs.arcweave.com/rest-api/localization) for choosing which language these values update.

Arcscript inside code blocks is also validated before saving. Invalid scripts or references return `400 Bad Request` with the title `Bad Request - invalid Arcscript`. See [General request rules](https://docs.arcweave.com/rest-api/overview#general-request-rules).