Start Parameter

The start parameter is a custom string parameter passed to a Mini App from an external environment. Its value is stored in the tgWebAppStartParam launch parameter.

This parameter is included in one of the following cases:

• The bot link contains the startattach query parameter.

https://t.me/botusername?startattach=ABC

• The Direct Link contains the startapp query parameter.

https://t.me/botusername/appname?startapp=ABC

In both cases mentioned above, the start parameter will be set to ABC.

INFO

This launch parameter is not included in the location hash. Instead, it can be found in the URL query parameters.

TIP

The value of this parameter is duplicated in the init data's start_param property.

Restrictions

• Maximum length: 512 symbols
• Allowed symbols: latin alphabet symbols, digits and underscore. The valid regexp for the value is /[\w]{0,512}/.