When a customer is created in Blueshift, a user attribute called bsft_control_bucket is assigned to the customer. Each customer, identified or anonymous, is randomly assigned a control bucket number between 1 to 100.
You can use this user attribute to split up segments into smaller groups or buckets, to create random segments, or for splitting up customers for A/B testing.
Here is an example of using the control bucket as a filter in a segment. This segment includes all customers who are assigned a control bucket number less than 25.