Q:

how to check if a user started a bot in telegram or not?

I'm developing a bot in telegram , here is my problem:
I have some posts in my channel which some inline_keyboards are attached to them. when a user press the button , next events happen in a bot and some messages show to a user. if user has been started the bot before , there is no problem , if not I have error. how should I check the user is member of my bot or not to handle this problem???

A:

There is no way to check if bot can talk to user or not without send message.
You can use url with https://t.me/Bot?start=some_data format, and you will receive /start some_data, please try this link yourself.

