Link previews

Link previews are available in some places in Nextcloud. There are 3 types of link preview:

• The ones for links that are supported by a reference provider

  • Without custom reference widget (uses a default generic style, image + title + description)
  • With custom reference widget (implemented by the app which supports the link)

• Default ones from OpenGraph information. This is the fallback for every unsupported link

Where do they appear?

The link previews provided by the Nextcloud reference system appear in the following places:

• Text (and Collectives pages, Notes, Deck card comments, Files comments etc...)

  • Directly in the document content, next to the links
  • Only one link preview per paragraph is rendered
  • Custom widgets can be rendered

• Talk

  • In the messages
  • Only one link preview per message is rendered
  • Custom widgets can be rendered

• Nextcloud Office

  • In the document content when hovering on links
  • Custom widgets are not rendered

How does it work?

The Nextcloud frontend asks the server to resolve the links via an API request. A rich object is returned as a response and is used by the frontend to render the preview.

The apps can optionally register a custom reference widget to render a specific rich object type (on the links it supports). Therefore the apps have complete freedom over how some previews look like.

Known link preview providers

• Collectives: Links to Collective pages
• Tables: Links to tables
• Deck: Links to boards, cards and comments
• Talk: Links to conversations
• GitHub integration: Links to GitHub issues, pull requests, comments and repositories
• GitLab integration: Links to Gitlab issues, merge requests, comments and repositories
• Zammad integration: Links to Zammad tickets
• Reddit integration: Links to subreddits, publications and comments
• Mastodon integration: Links to members and toots
• The Movie Database integration: Links to people, movies and series
• OpenStreetMap integration: Location links from OpenStreetMap, Google maps, Bing maps, Here maps and Duckduckgo maps
• Giphy integration: Links to GIFs
• Notion integration: Links to Notion documents
• Peertube integration: Links to videos