Building fast, resilient, and collaborative applications increasingly demands more than reactive UI frameworks and client-side state management. The next generation brings reactivity to the data layer itself—letting applications stay in sync with the backend automatically through a sync-engine architecture.

This talk explores how TanStack DB provides a practical path toward such architectures without requiring a rewrite or commitment to a particular backend. You can start with familiar API-driven workflows using TanStack Query and progressively adopt richer sync through Electric or any real-time backend. TanStack DB acts as the connective tissue: a unified, fast, reactive client database that keeps application state synchronized with your backend.

The focus of this presentation is TanStack DB’s newest capability: query-driven sync. Instead of preloading large collections or keeping oversized in-memory datasets, TanStack DB loads exactly the data a query needs—whether that’s a page of results, a slice of a document, or a relational join. Under the hood, an incremental view-maintenance engine built on differential dataflow ensures queries update efficiently as new data arrives.

This enables applications to handle larger data volumes, compute reactive queries efficiently, and move toward a true sync-engine architecture—without sacrificing the incremental adoption story that makes TanStack DB practical for real-world teams.