Why Your Next.js App Is Slow (And How to Fix It)
Marcos Rebitte
Lead Consultant
Next.js is one of the most powerful React frameworks available, but even the best tools can produce slow applications when misused. After optimizing dozens of Next.js applications, I've identified the most common performance pitfalls and how to fix them.
The Hidden Cost of Client-Side JavaScript
One of the biggest performance killers in Next.js apps is shipping too much JavaScript to the client. Every kilobyte of JavaScript needs to be downloaded, parsed, and executed before your app becomes interactive.
- 1.Analyze your bundle with @next/bundle-analyzer
- 2.Use dynamic imports for heavy components
- 3.Leverage Server Components in App Router
- 4.Avoid importing entire libraries when you only need one function
- 5.Use tree-shaking friendly imports
Image Optimization Mistakes
Images often account for the largest portion of page weight. Next.js provides excellent image optimization out of the box, but many developers don't use it correctly.
- 1.Always use next/image instead of img tags
- 2.Set appropriate sizes prop for responsive images
- 3.Use priority prop for above-the-fold images
- 4.Configure remote patterns in next.config.js
- 5.Consider using blur placeholders for better UX
Server-Side Rendering Pitfalls
SSR can dramatically improve perceived performance, but it can also slow things down if not implemented correctly. The key is understanding when to use SSR vs SSG vs ISR.
- 1.Use getStaticProps for data that doesn't change often
- 2.Implement ISR with appropriate revalidation times
- 3.Cache API responses when possible
- 4.Avoid blocking data fetches in getServerSideProps
- 5.Use streaming with React Suspense for faster TTFB
Database Query Optimization
Even with perfect frontend optimization, slow database queries can kill your app's performance. Here's how to ensure your data layer isn't the bottleneck.
- 1.Use database connection pooling
- 2.Implement query result caching
- 3.Add appropriate indexes to your database
- 4.Use pagination instead of loading all records
- 5.Consider edge functions for global low latency
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Marcos Rebitte
Lead Consultant
Marcos Rebitte is an entrepreneur and technology consultant with over 20 years of experience in technology and automation. Based in Myrtle Beach, SC, he is multilingual and combines international business experience with deep technical expertise.
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