Throughout the documentation, You will notice the use of UUIDs (or short: IDs) which are in GUID v4 format with a prefix.

This looks something like this: pre-xxxxxxxx-yyyy-xxxx-yyyy-xxxxxxxxxxxx, where pre- is the prefix. Some response payloads contain these IDs which basically serve as unique identifiers for the object being returned.

The prefix makes it easy to identify which API resource it's coming from.

Prefix list

Prefix      Resource
acc      Account
chl      Channel
cst      Customer
evt      Event
ety      Event Type
inv      Invite
irl      Invite Rule
ivt      Invite Template
qre      Questionnaire
qrt      Questionnaire Template
rev      Review
txn      Transaction