The API user key is a unique code associated with your Eventbrite account and enables you to import your contacts to FireText really easily.
To find it. Log into your Eventbrite account and follow: https://www.eventbrite.com/userkeyapi
Or, you can follow these 3 simple steps:
1. Log in to your Eventbrite account
2. Click on Account (top right)
click to view
3. Click on API user key (on the left)
click to view
To import contacts from Eventbrite, just copy and paste this in when prompted.