Route groups with (groupName) in NextJS - Performance & Optimization

Performance: Route groups with (groupName)

MEDIUM IMPACT

This affects the routing structure's impact on bundle size and initial page load speed by organizing routes without adding extra URL segments.

Organizing routes without affecting URL paths

NextJS

app/(admin)/dashboard/page.tsx
// Using (admin) as a route group keeps URL as /admin/dashboard without /admin prefix

Route groups organize code without adding URL segments, reducing navigation overhead and keeping URLs clean.

📈 Performance GainReduces unnecessary client-side routing steps, improving LCP by a few milliseconds

Organizing routes without affecting URL paths

NextJS

app/admin/dashboard/page.tsx
// Using folders without parentheses adds extra URL segments like /admin/dashboard

This adds extra URL path segments, increasing URL length and potentially triggering more client-side navigation and re-renders.

📉 Performance CostIncreases initial navigation complexity and can add small delays in LCP due to longer URL parsing

Performance Comparison

Pattern	DOM Operations	Reflows	Paint Cost	Verdict
Using folders without groupName (adds URL segments)	No extra DOM nodes	No reflows	Minimal paint cost	[X] Bad
Using route groups with (groupName) to hide folders	No extra DOM nodes	No reflows	Minimal paint cost	[OK] Good

Rendering Pipeline

Route groups affect how Next.js builds the routing tree and bundles code. They do not add extra DOM nodes but influence client-side routing and bundle splitting.

→Bundle Splitting

→Client-side Routing

→Initial Load

⚠️ BottleneckClient-side Routing complexity

Core Web Vital Affected

LCP

This affects the routing structure's impact on bundle size and initial page load speed by organizing routes without adding extra URL segments.

Optimization Tips

1Use route groups to organize routes without adding URL path segments.

2Avoid extra folders in URLs to reduce client-side routing overhead.

3Clean URLs help improve Largest Contentful Paint (LCP) by speeding navigation.

Performance Quiz - 3 Questions

How do route groups with (groupName) affect URL paths in Next.js?

A They remove routes from the app

B They organize routes without adding extra URL segments

C They add extra URL segments for each group

D They increase the number of DOM nodes

DevTools: Performance

How to check: Record a page load and navigation in the Performance panel. Compare the time spent in client-side routing and script evaluation.

What to look for: Look for shorter scripting and routing times when using route groups, indicating faster navigation and load.