Callstack Sep 23, 2025

Synchronizing Animated Values and Shared Values in React Native

Article Summary

Working with both React Native Animated and Reanimated in the same codebase? You're not alone. Callstack tackles the synchronization challenge that's been tripping up teams during gradual migrations.

React Native teams migrating from the legacy Animated API to Reanimated often need both libraries running side by side. This creates a tricky problem: how do you keep animated values in sync across two different animation systems without performance hits or janky UI?

Key Takeaways

Critical Insight

Teams can safely run Animated and Reanimated together by implementing proper value synchronization patterns that preserve performance during migration.

The article reveals a specific hook pattern that prevents the most common synchronization bug developers hit within hours of attempting this.

About This Article

Problem

When React Native teams migrate from the legacy Animated API to Reanimated, they need both libraries running at the same time. This creates real challenges. Performance can degrade and the UI can become janky during the transition.

Solution

Callstack suggests using bidirectional synchronization patterns with useAnimatedReaction and listeners. This bridges Animated.Value and SharedValue, making it possible to migrate gradually between the two animation systems without major rewrites.

Impact

Teams can keep 60fps performance while syncing values across both animation systems. This means they can adopt Reanimated step by step without losing frame rates or introducing UI jank.