Hi There,
The integration is managed via web hooks.
You establish a connection either a basic connection or OAuth.
The great thing is as Zephyr is a standalone solution you can potentially integrate with multiple Jira instances.
Useful if different teams on different projects use different instances.
It also enables automatic linkage between epics/stories to defects raised
Even tho this is all done via Zephyr the real time integration is bi-directional.
You will notice with newer versions of Zephyr we will have introduced the add on in Jira, this just gives non Zephyr Users some nice rich information on how the story or epic they are working on is performing in Zephyr without having to depend on logging into Zephyr.
Here is some more information on setting it up
https://zephyrdocs.atlassian.net/wiki/spaces/ZE/pages/2434072577/Jira+Integration+Zephyr+Enterprise
Setting up Jira:
https://zephyrdocs.atlassian.net/wiki/spaces/ZE69/pages/2864780014/Jira+Integration
KR
Vincent