Build a mobile to‑do app that syncs between devices, supports offline access, and pushes real-time updates while minimizing operational overhead. Which database approach do you use?

Firestore is ideal for this scenario because it's a NoSQL document database designed for mobile and web applications, offering built-in real-time synchronization and offline capabilities. Its client libraries handle data synchronization and offline persistence automatically, minimizing operational overhead. Listening to document changes directly provides real-time updates. Cloud SQL for MySQL is a relational database and would require significant custom development for real-time synchronization, offline access, and conflict resolution, increasing operational overhead. Bigtable is a wide-column NoSQL database optimized for large analytical workloads, not typically suited for real-time mobile app synchronization and offline features. Implementing SQLite on each device with Cloud Storage for synchronization would require extensive custom development for real-time updates, conflict resolution, and managing data consistency, which is complex and error-prone.