The article provides a detailed guide on implementing a waitlist feature in a software-as-a-service application using Clerk and Next.js, emphasizing the importance of fast feedback during the early stages of development. By configuring Clerk to allow user sign-ups while restricting access until explicitly permitted, developers can effectively manage user participation in beta testing. The guide explains setting up session tokens and user metadata to control user access, using Clerk middleware to redirect unauthorized users, and designing an admin dashboard for managing user permissions. It demonstrates the integration of these features using the "Cooking with Clerk" open-source application and provides instructions for setting up a local development environment. The article also covers securing the admin page to ensure only authorized users can access it, highlighting the utility of Clerk's metadata for storing user information and controlling application access.