This page discusses some of the options around integrating one JIRA instance with another, when trying to update an issue in one instance based on an update from another.

The solution is fairly complex, and Atlassian recommends working with a partner on a solution.

Options

• Option one is to use a notification scheme from the original instance, then a Create or Comment Mail Handler on the destination instance, to update the tickets across instances.
• Option two is to use a Jelly Service and the remote Api script to do something similar. You'd have to watch out for both problems above as well.

Challenges
A couple challenges with either approach:

1. You can run into a loop, where one instance updates the other, then vice-versa, ad infinitum.
2. You have a challenge of mapping which issue from the source maps to which issue from the destination.
   We thought you might be able to use a custom field from the source instance, then populate that with the issue from the destination instance, but you'd still need a bit of customisation from your mail handler to parse the email to do that mapping.

Consult our partner network for guidance.