Architecting Google Calendar Day View: Scaling Collaborative Time-Grid UX

Google Calendar's Day View reveals the hidden complexity in building modern calendar UIs at scale. Beyond basic drag-and-drop and event rendering, the system must solve real-time collaboration across distributed users, handle overlapping event layouts through interval partitioning, and maintain ACID consistency while fan-outing changes to collaborators within milliseconds. This design pattern is essential for any team-based scheduling platform.