How to react to start Telegram Bot parameters?

Question

Python

How to process requests with a parameter in start. Which is in the link t.me/UsernameBot/start=6353673
How to react to this start=6353673?

Answer 1

Equivalent to sending the command "/start 6353673"

Following a link with the start parameter will open a one-on-one conversation with the bot, showing a START button in the place of the input field. If the startgroup parameter is used, the user is prompted to select a group to add the bot to. As soon as a user confirms the action (presses the START button in their app or selects a group to add the bot to), your bot will receive a message from that user in this format:
/start PAYLOAD

https://core.telegram.org/bots#deep-linking