A sample signin bot in GoLang
This sample bot demonstrates how to use bot to help users sign-up and sign-in your website.
You could try the bot here https://t.me/kybersigninbot. Note that this sample doesn't actually sign you in, just give you the idea. In addition, actual implementation should save state to some database like Bolt.
The bot use Golang Telegram Wrapper telebot.
Recently, Telegram introduce the Login Widget so you might want to try it as an alternative approach for Telegram Sign-in.