A data layer is a structured way to manage and organize data on a website or application. It acts as a bridge between the user interface and the underlying data sources, allowing developers to collect, store, and retrieve information efficiently. This layer helps ensure that data is consistent and accessible across different platforms and tools. In web development, the data layer often works with tools like Google Tag Manager and analytics platforms to track user interactions. By using a data layer, businesses can gain insights into user behavior, improve marketing strategies, and enhance overall user experience.