Why Fetch When You Can Sync? Building Local-First Apps on a Sync Engine Architecture

QCon San Francisco 2025

Session Realtime

Why Fetch When You Can Sync? Building Local-First Apps on a Sync Engine Architecture

Tuesday Nov 18 / 05:05PM PST, Pacific DEKJ at Hyatt Regency, San Francisco

Abstract

Front-end has long been about reactivity frameworks and client-side state management. However, the alpha in these is receding. The next frontier, with much bigger gains across UX, DX and AX lies in extending reactive state management to the server with local-first apps built on a sync engine architecture.

Local-first apps built on sync are instant to use, always work and naturally support realtime collaboration. Eliminating stale data, loading spinners and manual data wiring. It's an ideal architecture for building AI apps and agentic systems where you have multiple users and agents collaborating on the same state. And the switch from imperative data fetching to declarative sync also makes LLM generated code more maintainable and suitable for production apps.

This talk introduces the principles of local-first and sync engine architecture and shows you how you can adopt these patterns today using TanStack DB, a new reactive client store for building super fast apps on sync that's now built directly into TanStack.

Interview

It's about building apps and agentic systems on a local-first, sync-engine architecture that makes apps fast, modern and naturally collaborative.

Software UX, DX, and AX are all being redefined and reinvented right now. Sync is key to building AI apps and agentic systems.

Slow apps. Loading spinners. Stale data. Migration challenges. Operational complexity. Scaling. Silos.

Switch one route/fetch/component of one of their apps to use TanStack DB.

Topics

Realtime Synchronization Infrastructure Frontend
76% senior dev or higher
1:11 speaker ratio
60+ practitioners

QCon San Francisco 2025 is a three day conference for senior software engineers, architects and team leads. An international program committee of working engineers selects every session. Patterns and practices, not products and pitches.

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