Configured with the use of a special server language. The request contains special keys, provided at the integration stage, and order data—just like the tracking code (order ID, amount, items, currency, etc.). The request is sent directly from the advertiser server (bypassing the browser and website). The simplest way to set up a postback request (without coding in the server language) is to use a module available for many popular CMS (1C-Bitrix, WooCommerce, OpenCart, ShopScript, Magento). This solution is considered the most reliable and, for integration through a module, the fastest.