Breaking the Re-render Chain: Our Migration from Context to Zustand

The Trendyol Affiliate Ads team migrated from React Context API to Zustand after hitting performance ceilings caused by cascading re-renders and lack of granular subscriptions. Their complex Ads Editor was generating 8,000+ function calls per interaction, causing visible UI lag. They adopted a feature-based store architecture with 7 independent Zustand stores for the create flow, using Immer for nested state updates and named DevTools instances for debuggability. The incremental, feature-by-feature migration avoided production risk. Results included a ~20% average reduction in interaction latency (31% in the most complex scenario), 80%+ reduction in Cumulative Layout Shift, 28% fewer UpdateLayoutTree recalculations, and a 60% drop in developer onboarding time. Key lessons: granular selectors are the primary performance driver, scoped stores beat a single global store, and the real bottleneck was React doing unnecessary work rather than slow JavaScript execution.