Unfurl attribute (Link Previews)
A Link Preview is a real-time subtitle of authenticated content that unfurls in Notion when an authenticated user shares an enabled link. Developers can build Link Preview integrations to customize how links for domains they own look when the links unfurl in a Notion workspace. The display of the Link Preview is customizable in terms of content and layout.
Link Previews can be displayed in their full format, or they can be shown as a βMentionβ.
Letβs first look at an example of a full-format Link Preview:

Here is the same link again but now as a Mention β a miniature version of a Link Preview that uses the same data.

A Link Preview or Mention displays data that is sent to Notion as an array of unfurl attribute objects. There are a number of optional attributes developers cannot. However, every array must contain a title attribute and a dev attribute.
Using the same Link Preview and Mention we saw above, letβs look at the array of unfurl attribute objects that would render these previews. The following payload creates the example Link Preview and Mention above:
Each unfurl attribute object in this array maps to a different customizable section of a Link Preview. (To learn more about each section, jump to The section value.

First, letβs let at the properties in each individual unfurl attribute object.
The unfurl attribute object
Each unfurl attribute object contains the following values:
Inline sub-type objects
The key of inline sub-type objects represents the kind of sub-type. The values of the key are the value to display and the section of the Link Preview where the value is rendered.
The dev attribute
Every array of attribute objects that is sent to Notion to create a Link Preview must also include a dev attribute. The attribute indicates the developer or company who created the Link Preview. It takes the following format:
Embed sub-type child objects
You can use the embed sub-type object to add rich content like JPGs, GIFs, or iFrames to your Link Preview.

All embed sub-type objects contain: a src_url field that is a link to the embed, and an object whose key is the sub-type of the embed and whose value is an object indicating the section of the Link Preview where the value is rendered.
Thereβs no need to ask a user to log in to your service in an iFrame embed. If theyβre using a Link Preview, then theyβve already authenticated.
The section value
The section value of an unfurl attribute object defines where an attribute is rendered in the Link Preview or Mention.


A section is specified in the sub-type object for the attribute. Refer to the table below for details about each section and its valid parent sub-types.