userContact

A user that is a contact of the current authorized user.

userContact#f2fb8319 id:int first_name:string last_name:string access_hash:long phone:string photo:UserProfilePhoto status:UserStatus = User;

Name	Type	Description
id	int	User identifier
first_name	string	First name (see below)
last_name	string	Last name (see below)
access_hash	long	Checksum, dependent on user ID
phone	string	Phone number
photo	UserProfilePhoto	Profile photo
status	UserStatus	Current status
username	string	Username

The first_name and last_name fields are assigned by the server as follows:

If the user id is in the current user's phone Contacts and the name for this contact was imported along with the contact, then that name will be used.
If the user id has the current user in his Contacts, then the fields first_name, last_name will contain the name the user id supplied.
If none of the conditions 1,2 are observed, both fields are returned empty.

Telegram is a cloud-based mobile and desktop messaging app with a focus on security and speed.