Modern fan engagement requires realtime experience platforms that deliver low latency and reliability to replace the in-person experience. These platforms must meet four key requirements: realtime performance, scalability, ROI maximization, and offering composable realtime services. Realtime experiences are crucial for fan engagement, with companies needing to build or buy the right technology to succeed. The infrastructure required includes high reliability, availability, and elasticity to handle extreme viewerships and unforeseen events. Design patterns such as batching, aggregating, and partitioning can help optimize costs while maintaining user experience. A comprehensive realtime platform offering a suite of products is essential for delivering immersive experiences.