> ## Documentation Index
> Fetch the complete documentation index at: https://developers.notion.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> Learn how link previews work and what you need to build them.

export const developerConnectionsUrl = "https://www.notion.so/developers/connections";

A Link Preview is a real-time excerpt of authenticated content that unfurls in Notion when an authenticated user shares an enabled link. Instead of logging in to multiple tools at a time, collaborators can use Link Previews to centralize their work in Notion.

<Frame caption="An example Link Preview for a GitHub workflow">
  <video controls className="w-full aspect-video rounded-xl" src="https://mintcdn.com/notion-demo/gQdVRy6l7aPTpzMm/images/docs/link_unfurling.mp4?fit=max&auto=format&n=gQdVRy6l7aPTpzMm&q=85&s=fb32ddf0c1c56950202668cb06b25b45" data-path="images/docs/link_unfurling.mp4" />
</Frame>

With the Link Previews API, you can set up connections that share a Link Preview for your product. For example:

* **Trello** created a Link Preview that unfurls information about a linked task.
* **Figma** built a Link Preview that shares a linked board’s image preview and corresponding metadata.
* **Amplitude** created a Link Preview that shares a linked graph in an iFrame along with an interface to modify the graph.
* **Slack** built a Link Preview that unfurls a linked message’s content and author.

If your customers use Notion, then building a Link Preview can help them to integrate your product into their existing workflows.

## How Link Previews work

A user shares a Link Preview enabled URL. Notion detects enabled URLs based on the settings that you provide when you create the connection. If it’s the first time that a user has shared an enabled URL, then Notion kicks off an auth flow to authenticate with your service. After the user authenticates, Notion and your service exchange tokens that enable your connection to share a Link Preview in the user’s workspace.

<Frame caption="A diagram of the Link Preview flow">
  <img src="https://mintcdn.com/notion-demo/LHm9qfrJYJOPRxs6/images/docs/e121163-lp_overview.png?fit=max&auto=format&n=LHm9qfrJYJOPRxs6&q=85&s=ca57bf5daad1fda57bb7f369a94f7109" width="1800" height="1200" data-path="images/docs/e121163-lp_overview.png" />
</Frame>

Your connection also detects any changes to the data embedded in the Link Preview, and alerts Notion when the Link Preview needs to be updated.

Notion alerts your connection when a Link Preview is deleted, so that your connection can stop listening for updates.

## Build your own Link Preview connection

Notion offers the tools for developers to build their own Link Preview connection to unfurl links for a specified domain.

<Frame caption="Anatomy of an unfurled link preview">
  <img src="https://mintcdn.com/notion-demo/LHm9qfrJYJOPRxs6/images/docs/57f4b0d-Untitled_1.png?fit=max&auto=format&n=LHm9qfrJYJOPRxs6&q=85&s=f620c2ae86311158ff4d015d6c281d35" width="1378" height="818" data-path="images/docs/57f4b0d-Untitled_1.png" />
</Frame>

Using the <a href={developerConnectionsUrl}>Developer portal</a> and Notion’s public API, developers can customize each section of a Link Preview to show relevant data to users.

### Link Previews vs. Embed blocks

If you have used [Embed blocks](/reference/block#embed) in Notion’s UI before, you may be wondering how Link Previews differ from them. Embeds allow Notion users to embed online content — such as a webpage, PDF, and more — directly in a Notion page. This allows users to preview the content without leaving Notion.

Link Previews are similar but specifically allow developers to determine and customize the content displayed when an authenticated link is unfurled. Rather than embedding the full content of a webpage or file being shared, Link Previews pull data from a linked page and display it in an unfurled format that has been specified by the developer.

Since Link preview connections require [OAuth 2.0](https://www.oauth.com/) authentication, unfurled link content will update as the data being shared updates. For example, if a GitHub pull request is shared as a Link Preview, the data displayed in the preview will update as the pull request updates (e.g. when it is merged).

<Info>
  To learn more about Embed blocks, read our [reference docs](/reference/block#embed) and [Help Centre guide](https://www.notion.so/help/embed-and-connect-other-apps).
</Info>

## Requirements for building a Link Preview connection

<Warning>
  To build a Link Preview connection, developers must first apply for access to the feature through the [Notion Link Preview API request form](https://notionup.typeform.com/to/BXheLK4Z?typeform-source=developers.notion.com).

  Additionally, all Link Preview connections published for distribution require a review from Notion's platform and security teams.
</Warning>

In order to build Link Preview connections, you need to meet the following requirements:

* Support OAuth 2.0 in your application, or be ready to implement it.
* Own the domain that you’d like to set up with Link Preview enabled URLs.

If you meet these requirements and you’d like to start building with the Link Previews API, then please [request access](https://notionup.typeform.com/to/BXheLK4Z?typeform-source=developers.notion.com).

## Next steps

To learn how to build your own Link Preview connection, read:

* [Build your own Link Preview connection](/guides/link-previews/building-a-link-preview) guide

## Link Preview connection resources

To learn more about Link Previews, see the following resources:

* [Build your own Link Preview connection](/guides/link-previews/building-a-link-preview) guide
* [API reference docs for the Link Preview unfurl attribute object](/reference/unfurl-attribute-object)
* [Help Centre](https://www.notion.so/help/guides/notion-api-link-previews-feature) guide