Slack offers a robust platform for building interactive notification systems for SaaS applications, allowing users to engage directly with app notifications through elements like buttons, dropdowns, and dialog boxes. This feature enhances user decision-making and application value. The text details the development of a bi-directional messaging app using the Bolt framework for Node.js, guiding readers through setting up a Slack app, configuring environment variables, and employing Slack's Block Kit framework to create interactive messages. The app listens for specific message triggers, and users can interact with these messages via buttons and dropdowns, which send event data back to the server for tailored responses. The process includes setting up OAuth, enabling socket mode, and subscribing to events to establish communication with Slack's API. The text also highlights the capabilities of Knock for managing Slack notifications and using Block Kit for designing actionable messages, demonstrating how these tools can optimize team workflows and communication.