Variables in Botmother

In the builder, you can store and use not only static information but also variable information depending on the data entered by a user. The values that are changed are called variables.
There are basic variables for each user. We see them in User State section as soon as the user writes to the bot.
Variables are displayed as "Variable": "Variable value".
{
  "this_user": {
    "platform_id": User ID in the platform,
    "platform": "Platform"            
    "firstname": "Username",
    "lastname": "User surname",
    "full_name": "Full username",
    "username": "Username in the platform",
    "language": "Interface language",
    "country": "Country in device settings",
    "bm_id": Unique user ID in the bot,
    "phone": "User's phone number, only on WhatsApp"                       
  },
  "last_input": "The last user input"
}
Some variables take value null. It means that there is no corresponding information on this platform. For example, it often happens on Telegram and Viber, where the last name is not required.
The key variable is last_request, which appears after the request to the server and contains the response to the request.