Add a custom linkifier

This feature is only available to organization owners and administrators.

Linkifiers make it easy to refer to issues or tickets in third party issue trackers, like GitHub, Salesforce, Zendesk, and others. For instance, you can add a linkifier that automatically turns #2468 into a link to https://github.com/zulip/zulip/issues/2468.

If the pattern appears in a topic, Zulip adds an Open () button to the right of the topic in the message recipient bar that links to the appropriate URL.

If you have any trouble creating the linkifiers you want, please contact Zulip support with details on what you're trying to do.

Add a custom linkifier

  1. Go to Linkifiers.

  2. Under Add a new linkifier, enter a Pattern and URL template.

  3. Click Add linkifier.

Common linkifier patterns

The following examples cover the most common types of linkifiers, with a focus on linkifiers for issues or tickets.

This is a pattern that turns a # followed by a number into a link. It is often used to link to issues or tickets in third party issue trackers, like GitHub, Salesforce, Zendesk, and others.

  • Pattern: #(?P<id>[0-9]+)
  • URL template: https://github.com/zulip/zulip/issues/{id}
  • Original text: #2468
  • Automatically links to: https://github.com/zulip/zulip/issues/2468

To set up linkifiers for issues or tickets in multiple projects, consider extending the #2468 format with project-specific variants. For example, the Zulip development community uses #M2468 for an issue in the repository for the Zulip mobile app, #D2468 and issue in the desktop app repository, etc.

  • Pattern: #M(?P<id>[0-9]+)
  • URL template: https://github.com/zulip/zulip-mobile/issues/{id}
  • Original text: #M2468
  • Automatically links to: https://github.com/zulip/zulip-mobile/issues/2468

For organizations that commonly link to multiple GitHub repositories, this linkfier pattern turns org/repo#ID into an issue or pull request link.

  • Pattern: (?P<org>[a-zA-Z0-9_-]+)/(?P<repo>[a-zA-Z0-9_-]+)#(?P<id>[0-9]+)
  • URL template: https://github.com/{org}/{repo}/issues/{id}
  • Original text: zulip/zulip#2468
  • Automatically links to: https://github.com/zulip/zulip/issues/2468

The following pattern linkfies a string of hexadecimal digits between 7 and 40 characters long, such as a Git commit ID.

  • Pattern: (?P<id>[0-9a-f]{7,40})
  • URL template: https://github.com/zulip/zulip/commit/{id}
  • Original text: abdc123
  • Automatically links to: https://github.com/zulip/zulip/commit/abcd123

Advanced linkifier patterns

Linkifiers are a flexible system that can be used to construct rules for a wide variety of situations. Linkifier patterns are regular expressions, using the re2 regular expression engine.

Linkifiers use RFC 6570 compliant URL templates to describe how links should be generated. These templates support several expression types. The default expression type ({var}) will URL-encode special characters like / and &; this behavior is desired for the vast majority of linkifiers. Fancier URL template expression types can allow you to get the exact behavior you want in corner cases like optional URL query parameters. For example:

  • Use {+var} when you want URL delimiter characters to not be URL-encoded.
  • Use {?var} and {&var} for variables in URL query parameters.
  • Use {#var} when generating # fragments in URLs.

The URL template specification has brief examples and detailed examples explaining the precise behavior of URL templates.

Linking to documentation pages

This example pattern is a shorthand for linking to pages on Zulip's ReadTheDocs site.

  • Pattern: RTD/(?P<article>[a-zA-Z0-9_/.#-]+)
  • URL template: https://zulip.readthedocs.io/en/latest/{+article}
  • Original text: RTD/overview/changelog.html
  • Automatically links to: https://zulip.readthedocs.io/en/latest/overview/changelog.html

This pattern uses the {+var} expression type. With the default expression type ({article}), the / between overview and changelog would incorrectly be URL-encoded.

Linking to Google search results

This example pattern allows linking to Google searches.

  • Pattern: google:(?P<q>\w+)?
  • URL template: https://google.com/search{?q}
  • Original text: google:foo or google:
  • Automatically links to: https://google.com/search?q=foo or https://google.com/search

This pattern uses the {?var} expression type. With the default expression type ({q}), there would be no way to only include the ? in the URL if the optional q is present.