Telegram Bot HandbookCreating Links to Bots
Regular links
Links to bots ar similar to links to users, groups, and channels: the link t.me/examplebot opens the bot with the username @examplebot.
There is also a direct link: tg://resolve?domain=examplebot
About tg:// links
Links starting with tg:// may replace t.me links or do special actions. For example, the link tg://settings opens settings in Telegram apps.
Such links are listed in API documentation and in the unofficial @DeepLink channel.
Deep links
Deep link is a link of form t.me/examplebot?start=YOUR_TEXT. They are used to start a dialog with the bot with some initial parameters.
This works as following. Once a user visits a deep link, they see a dialog with the bot and the "Start" button (even if they have already started the dialog). A click on the button sends /start YOUR_TEXT. The user, however, sees only /start, like if starting the bot regularly.
Deep links are often used for referral programs: for example, the parameter can be ID of the user who shared the link.
The direct link is similar: tg://resolve?domain=examplebot&start=YOUR_TEXT
Deep links for groups
There are deep links for groups as well..
The link of form t.me/examplebot?startgroup=YOUR_TEXT opens a chat selection dialog to add the bot; once the bot is added, the command /start YOUR_TEXT will immediately be sent to the group.
The direct link: tg://resolve?domain=examplebot&startgroup=true