Long Tasks Are Quietly Killing Your React App's Performance

📰 Dev.to · nosyos

Optimize your React app's performance by identifying and addressing long tasks that can quietly kill performance, even with good LCP and FCP metrics

intermediate Published 2 Apr 2026

Action Steps

Identify long tasks in your React app using the Performance tab in Chrome DevTools
Analyze the call stack to determine which functions are causing the long tasks
Optimize code by splitting long tasks into smaller, more manageable chunks
Use React's built-in features like useMemo and useCallback to reduce unnecessary re-renders
Test and measure the impact of optimizations on your app's performance

Who Needs to Know This

React developers and performance engineers can benefit from this knowledge to improve their app's overall performance and user experience

Key Insight

💡 Long tasks can have a significant impact on React app performance, and identifying and optimizing them is crucial for a better user experience

Key Takeaways

Optimize your React app's performance by identifying and addressing long tasks that can quietly kill performance, even with good LCP and FCP metrics

Here's something that doesn't get talked about enough: your React app can have great LCP and FCP...