Next.js And React Expert
Selective Reading Rule
Start with:
references/usage-routing.mdreferences/quality-checklist.md
Then load only the inherited docs, scripts, assets, or examples that match the user's actual task.
Selective Reading Rule
Start with:
references/senior-master-standard.md
Pick the narrowest file that matches the current bottleneck:
references/performance-investigation-playbook.mdto structure the investigationreferences/app-router-checklist.mdwhen reviewing App Router boundaries, fetching, and caching1-async-eliminating-waterfalls.mdfor sequential data-fetching and request chains2-bundle-bundle-size-optimization.mdfor large bundles and slow interactivity3-server-server-side-performance.mdfor SSR and server-route performance4-client-client-side-data-fetching.mdfor client cache and request behavior5-rerender-re-render-optimization.mdfor excessive re-renders6-rendering-rendering-performance.mdfor rendering bottlenecks and large lists7-js-javascript-performance.mdfor hot-path JavaScript issues8-advanced-advanced-patterns.mdfor advanced React execution patterns9-cache-components.mdfor Next.js 16 cache components and partial prerendering
Purpose
Improve React and Next.js systems by fixing the highest-impact bottlenecks first.
Do not micro-optimize while bigger issues like waterfalls, bundle bloat, or bad boundaries remain.
Use This Skill When
- a page or flow feels slow and the bottleneck is not yet isolated
- React code re-renders too often
- Next.js data fetching or rendering strategy needs review
- bundle size or client JavaScript volume is harming user experience
- modern Next.js caching choices need to be made deliberately
Priority Order
- Eliminate waterfalls.
- Reduce unnecessary shipped JavaScript.
- Fix bad server-client boundaries.
- Tackle rerender and rendering hotspots.
- Only then consider lower-level JavaScript polish.
Review Heuristics
- Prefer server work when the client does not need ownership.
- Keep data fetching parallel where dependencies allow.
- Ship less code before trying to execute shipped code faster.
- Measure before and after when possible.
- Do not add memoization by reflex; fix structure first.
Common Focus Areas
- route-level waterfalls
- oversized client components
- unnecessary client state
- missing streaming or suspense boundaries
- poor cache behavior
- list rendering and virtualization problems
Good Outcomes
A strong performance pass should end with:
- the main bottleneck identified
- the chosen optimization path explained
- the relevant checks run or recommended
- the codebase left simpler, not just trickier
Related Skills
frontend-designwhen UX and implementation quality interactweb-design-guidelinesfor interface-level auditsperformance-profilingfor broader measurement strategyapi-patternswhen backend shape is creating frontend waterfalls