Push notification fallbacks are essential for ensuring message delivery when primary channels fail, such as when users disable notifications or face connectivity issues. Courier's intelligent multi-channel routing system automatically switches to secondary channels like email, SMS, Slack, or Microsoft Teams to maintain communication reliability. The system allows for configurable channel routing, enabling dynamic adjustments based on user preferences, message urgency, and regional differences. Best practices for setting up fallbacks include respecting user preferences, optimizing costs by reserving SMS for high-priority messages, and monitoring performance to fine-tune strategies. Advanced patterns consider geographic routing and user behavior to personalize delivery, while handling provider failures through redundancy within each channel. The aim is to balance timely delivery of critical alerts with user experience, ensuring messages reach their intended recipients without overwhelming them with duplicates.