Jira Service Desk user authentication against an external database

We are trying to implement sso between our application and Jira Service Desk. Our application users are stored and authenticate against MySQL db.
Can we authenticate jira users against an external db?without using any directory?

You’ll need have a directory of some kind to authenticate the users. Is this a commercial app that you’re offering others? Or is it your own in-house custom app? If it’s a one-off custom in-house app - you might want to check the user community at community.atlassian.com to see if anyone else have suggestions.

If it’s the commercial app - take a look at Atlassian seraph.