Slack notifications can be enhanced using Slack's Block Kit, a UI framework that allows for the creation of complex messages using JSON. Block Kit enables developers to incorporate text, images, interactivity, and design elements into notifications, enhancing user engagement beyond simple text or emoji alerts. By leveraging Block Kit, notifications can include various features such as links, interactive elements like multi-select options, and checkboxes, allowing users to perform actions directly from Slack. The framework supports the integration of images and videos, requiring specific fields for proper rendering and interaction. For developers, tools like Block Kit Builder facilitate the creation and preview of JSON payloads, helping to manage syntax and structure effectively. Additionally, platforms like Knock provide solutions for managing notifications across multiple channels, including Slack, by allowing seamless integration of Slack messages built with Block Kit into their systems, offering features like OAuth for authentication and built-in UI components for rapid deployment.