Google Publisher Tag (GPT) is Google's ad tagging library. It allows publishers to define ad slots on their pages, request ads from Google Ad Manager (GAM), and render them in a flexible and responsive manner. It handles various aspects of ad serving including impression tracking, click tracking, competitive exclusions, and frequency capping. The script is designed to operate asynchronously, preventing it from blocking page rendering and ensuring a fast user experience. It supports a wide range of ad types, including display, native, and video ads. GPT also provides robust integration capabilities for managing user consent for personalized advertising, which is crucial for compliance with global privacy regulations such as GDPR and CCPA. When a webpage loads the GPT library, it communicates with Google's ad servers to fetch ad creatives based on the configured ad slots on the page, the publisher's targeting criteria, and the user's consent settings. The library then dynamically injects these ads into the designated containers within the webpage's HTML structure. This dynamic loading and rendering ensure that ads are displayed effectively and efficiently, tailored to both the user and the page content.