Why and How would I create an application link between two Jira cloud sites?

[#1]

Since there are a lot of misconceptions on this topic, this article is written to shed some light on it.

Application links between Jira cloud sites act as digital handshakes, enabling seamless integration while maintaining security. Here's why and a reference to an article on how to set them up. But we will focus on what it can - and can't achieve.

Why create an application link and what do they provide?

1. Centralized Resource Sharing

Display related issues or data from one Jira site within another. Consider, your team (uses Jira and lets call it site A) is collaborating or delivering services to another company who have their own Jira site (site B) to track and work. When you want to create a link/reference a work item from Site A to Site B, all you have to do is create an application link between these sites so you know the related workitem from Site B in Site A itself. You can also track its status, assignee, summary and issuekey.

In the screenshot below, KAN-1 from site A is linked to ENGS-28 from site B. As you can see, it is similar to the regular Jira issue linking, but the linked issue is from a different site.

2. Unified User Experience

Reference information from a different site on yours without having to switch between sites. Let us say, you need to reference a confluence document that your vendor/client has prepared for a task in your internal site workitem. You can simply search for the page inside your workitem and link it up, the same way you do with your site's confluence

3. Enhanced Delivery

It not only works in Jira, but confluence as well. Let's say you want to review a list of all tickets that your vendor/client is working on. So, showing workitems from Site B on Site A confluence. You just have to use the Jira macros and choose list of issues from Site B Jira (provided there is an existing application link from Site B Jira and Site A confluence).Now this is a fantastic capability of application links that I am so eager to reference here.

Application links have come a long way from just being able to provide a link to external content, you can embed and view much more data from Site B on A.

How to set up the Link?

It is mostly straightforward. I do not want to extend this article by copying data which is already available here.

What they don't provide

1. Cross-site JQL searches

You cannot query issues from Site B in Site A's JQL searches. For example, the following query will fail from Site A.

Project = "Site B Project"

2. Data Synchronization

You cannot write changes to Site B from A. Though the status changes, updates to assignee etc are reflected in the link you cannot change value for a Site B workitem from Site A.

3. Automation rules

You cannot run automation rules on Site B's workitems from Site A. Though related issues functions find all work items related to a specific item, it will not find workitems from a different site.

To keep it simple, think of application links as a pathway to just reference fixed information from another source. It does not bring the entity from Site B to Site A or vice versa.

4. User Permissions

Access controls remain site-specific unless explicitely mirrored. Let's take the example of issue linking from Site A to B. Unless you have access to view projects in Site B, you cannot view existing links nor can you add new links in Site A.

5. Creating work items on Linked sites

While application links allow linking existing issues across sites, they do not enable creating new issues directly on the remote Jira site from the local site. This limitation requires manual creation or advanced automation setups using REST APIs

6. Linking cloned sites

Application links cannot be used to link a Jira site with its cloned counterpart (e.g., a copied instance, a Jira site exported from the source site and then imported onto a second site). This is due to unique identifiers that prevent seamless integration between cloned environments.

7. Advanced reporting across sites

Application links cannot generate consolidated reports or dashboards that span multiple Jira instances. Reporting tools must aggregate data externally using APIs or export options.

What other apps can I use to build on external site/product integration.

There are several wonderful third party plugins that provide cross site/product sync including bidirectional data sync.

Be it, you are looking for basic issue sync between Jira sites or for cross product integration, there are multiple ones based on which product you want to accomplish your goals. For more information on this feel free to browse for them in Atlassian Marketplace.

Please post if you have any queries in the comments and I will be happy to assist you.

[Matt Doar _Adaptavist_]

That's a useful summary, thanks. ScriptRunner Connect https://www.scriptrunnerhq.com/atlassian-apps/jira/scriptrunner-connect is another approach too, by my employer Adaptavist