Telegram Chat IDs: Negative Numbers and the -100 Prefix

The shape of a chat_id tells you what it is

A Bot API chat ID (chat_id) is a single number, but its sign and its first digits are enough to tell you what kind of chat it belongs to. The values below are examples.

Inside Telegram's own protocol (MTProto), groups and channels have positive numbers of their own. The Bot API puts all of them into one number space so they never collide: basic groups get a minus sign, and supergroups and channels are shifted further down so they begin with -100. For how the three kinds of chat differ in the API, see the four Telegram APIs.

Three common mistakes

The ID changes when a group becomes a supergroup

Some changes to a basic group, such as turning on certain admin features or making it public, upgrade it to a supergroup, and it gets a new -100… ID. If your bot sends to the old ID, the error response includes the new one in migrate_to_chat_id. Update the stored value with it and send again.

{
  "ok": false,
  "error_code": 400,
  "description": "Bad Request: group chat was upgraded to a supergroup chat",
  "parameters": { "migrate_to_chat_id": -1001234567890 }
}

The group itself also receives a service message carrying the same new ID, so a bot that reads updates can update its records before it ever sends.

Storing it in a 32-bit integer

A -100… ID does not fit in 32 bits. The Bot API documentation says to store chat IDs as a signed 64-bit integer or a double-precision float. Languages that keep all numbers as floats, such as JavaScript, handle this range safely.

Dropping the -100

You can shorten an ID for display, but always send it in its original form. 1234567890 and -1001234567890 are different chats to the API.

How to find the ID of your own chat

1. Add your bot to the group or channel, or for a private chat, have the user start the bot.
2. Send one message there.
3. In the update your bot receives, message.chat.id is that chat's ID. How to receive updates is in webhooks vs long polling.

For a public group or channel you can put @username in place of the number. A private one only has its numeric ID.

To send a message once you have the ID, see your first Bot API requests.