|user\_id|[int](../types/int.md) | Yes|ID of the user that pressed the button|
|msg\_id|[InputBotInlineMessageID](../types/InputBotInlineMessageID.md) | Yes|ID of the inline message with the button|
|chat\_instance|[long](../types/long.md) | Yes|Global identifier, uniquely corresponding to the chat to which the message with the callback button was sent. Useful for high scores in games.|
|data|[bytes](../types/bytes.md) | Optional|Data associated with the callback button. Be aware that a bad client can send arbitrary data in this field.|
|game\_short\_name|[string](../types/string.md) | Optional|Short name of a Game to be returned, serves as the unique identifier for the game|