How I Reduced My Dashboard Bundle Size from 1.72 MB to 299 KB for Faster Loading

As our product grew, the dashboard started feeling slower than expected, which impacted how quickly users could access key information and complete tasks. Longer load times risked frustrating users and reducing engagement. Looking into performance, I found the initial JavaScript bundle was 1.72 MB, which contributed to slower loading, especially on slower networks.

Understanding the Problem

Even with React optimizations like React.memo and useCallback, first load performance can be overlooked. A large initial bundle affects user experience regardless of rendering optimizations.

Step 1: Optimize Imports

Many components were loaded upfront, even if they weren’t immediately visible. Every large component added to the main bundle, increasing download size.

Step 2: Lazy Loading

The solution? React.lazy + Suspense. Lazy loading splits the code into chunks and loads components only when needed.

Instead of importing components directly:

import { FrameworkProgress } from "@/components/dashboardWidget/FrameworkProgress";

You can use:

const FrameworkProgress = React.lazy(() =>
  import("@/components/dashboardWidget/FrameworkProgress")
);

Key points:

React.lazy() loads components only when rendered.

Suspense shows a fallback UI while loading.

This reduces the initial bundle size and improves first load performance.

The Result

After applying lazy loading and optimizing imports:

Before: 1.72 MB
After: 296 KB

The dashboard now feels much faster, even on slower networks.

Lessons Learned

First load size matters. Optimizations like memoization are useful, but bundle size impacts user experience directly.

Lazy loading is simple but effective. React.lazy() + Suspense can dramatically improve performance.

Conclusion

Optimizing dashboard performance isn’t just about micro-optimizations inside React. Structuring code smartly and using lazy loading can significantly reduce bundle size and improve user experience.