Launch Parameters

The launch parameters are the list of parameters that is passed by the native Telegram application to the Mini App. It helps the developer to find out the characteristics of the Telegram application, the current device, get basic information about the user and much more.

Transmission Method

In a web environment, one of the simplest and fastest ways to transfer data between locally running applications is by specifying it in the address bar. A server can include data in the URL's hash, making it accessible to the client application. Similarly, Telegram Mini Apps use this approach, with the Telegram client environment sending data to the Mini App through the URL's hash. This enables the Mini App to access essential information upon launch.

The native Telegram application transmits a list of these parameters in the dynamic part of the URL (in the hash #). To access these parameters, you need to use the window.location.hash property in your JavaScript code.

Extraction

It is important to remember that hash is a string property, while Telegram transmits a whole list of properties, after which the question arises about formatting and processing this list. In fact, everything is quite simple.

The native Telegram application passes the list of launch parameters as query-parameters and saves the resulting string in window.location.hash. For this reason, in order to extract the launch parameters, it is enough to perform the following operation:

const hash = window.location.hash.slice(1);
console.log(hash); // tgWebAppData=...&tgWebAppVersion=6.2&...

const params = new URLSearchParams(hash);
console.log(params.get('tgWebAppVersion')); // "6.2"

TIP

However, users have the capability to refresh the current application without exiting it. If the application uses hash routing, it may lose the initial hash after some time. Therefore, it's advisable to save this data during the initial launch of the application.

Parameters List

tgWebAppVersion

The current Telegram Mini Apps version used by the native application. This parameter is important to use, for example, before calling the Telegram Mini Apps methods to make sure, they are supported.

tgWebAppData

Contains data describing the current user, data sign, and also some useful values. To learn more, visit the Init Data page.

tgWebAppPlatform

Telegram application identifier. It can be used as a factor determining the visual style of the application, for example, when, depending on the device, the developer needs to display components that are different visually.

tgWebAppThemeParams

Parameters of the native Telegram application theme. This parameter can be used to style the application even at the moment of rendering the loader.

The value of this parameter is a JSON object converted to the string. To get a more user-friendly value, it is enough to use the JSON.parse method.

const theme = {
  bg_color: '#212121',
  text_color: '#ffffff',
  hint_color: '#aaaaaa',
  link_color: '#8774e1',
  button_color: '#8774e1',
  button_text_color: '#ffffff',
  secondary_bg_color: '#0f0f0f',
};

tgWebAppShowSettings

Parameter used only by Telegram SDK to show the Settings Button on startup. It has no other meaning to external developers.

tgWebAppBotInline

This parameter is being added in case the current application is launched in inline mode. This allows calling such Telegram Mini Apps method as web_app_switch_inline_query.

tgWebAppStartParam

Parameter that contains a custom string value passed in the bot or application link. Learn more.

tgWebAppFullscreen

Parameter indicating if the application is currently launched in the fullscreen mode.