Here is what JunctionBot says in it's readme for example:
If you are admin of the source channel, keep in mind that the bot will enter there with one of its accounts. Do not ban the bot, otherwise it will not be able to get messages from there.
Now send me a link to a destination channel, to where you want to copy messages.
For public channels, you can send me a channel @name. It starts with the symbol @. Please note that you cannot use the full descriptive name of the channel, you need exactly that short @name, by clicking on which you can go to the channel itself.
For private channels, send me an invitation link.
If you know the channel ID, you can send it to me as a number.
Hi,
I want to validate an app idea that requires listening to messages across a list of channels. According to what I was able to find, it's only possible with "user bots" https://stackoverflow.com/questions/42674340/how-to-join-my-telegram-bot-to-public-channel
Here is what JunctionBot says in it's readme for example:
Is that currently possible with the ex_gram?
Thanks!