contact object:
Identifier
string
required
The identity of the contact on the channel, up to 200 characters.
On a Shortext endpoint, the identifier is only unique within your company: the same
user-42 in two companies is two different contacts. The API always gives you back your own id.
Profile
All the profile fields are optional when you start a conversation or send an inbound message (the v1.0POST /messages/send requires lastname).
The profile updates the contact Shortext keeps; the agent uses the name and the language to address the contact.