Building a notification center for web and mobile apps can be a complex process requiring months of development if done from scratch, given the need to manage state across various notification channels like push, email, SMS, and in-app notifications. The guide suggests using Courier's platform to streamline this process, offering a unified API that supports multiple channels, automatic state management, and real-time updates through managed WebSocket infrastructure. Courier provides pre-built, customizable UI components for React, React Native, iOS, Android, and Flutter, allowing developers to implement production-ready notification centers in days. The platform also offers advanced features such as multi-channel routing, user preference management, and analytics, enabling teams to deliver timely, relevant notifications that enhance user engagement while reducing the risk of churn due to notification fatigue. By leveraging Courier, development teams can focus on integration rather than infrastructure, significantly shortening the time to market and simplifying ongoing maintenance.