Hello proimpact,
We currently don’t integrate with Constant Contact. If Constant Contact somehow integrates with Eventbrite or Facebook, we do have API plugins for those. (Although, I seriously doubt this would work seamlessly)
If you have a moment, we’d love for you to submit your idea to our UserVoice forum. We take user ideas and contributions very seriously, and many times their ideas end up in our future releases.
Cheers!
– Casey Driscoll