Web Performance (Interview Prep)

A structured roadmap of performance fundamentals that show up in real frontend interviews and real production apps. Start top-to-bottom.

Series: Web Performance

Progress: 0/16

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Web Performance Roadmap: Start Here (2 hours / 1 day / 1 week)

A guided entry point into the Web Performance roadmap with curated paths (2 hours / 1 day / 1 week) + exactly what to measure and why it matters in interviews.

  1. 1

    Web Performance Roadmap: Start Here (2 hours / 1 day / 1 week)

    A guided entry point into the Web Performance roadmap with curated paths (2 hours / 1 day / 1 week) + exactly what to measure and why it matters in interviews.

    4 min read
  2. 2

    Core Web Vitals: The Mental Model (LCP, INP, CLS)

    A high-signal mental model for LCP, INP, and CLS: what they measure, what actually moves the needle, and how to debug them in real apps.

    ~18 min
  3. 3

    Performance Debugging Playbook (Chrome DevTools + Real Signals)

    A senior-level workflow to diagnose performance issues: find the bottleneck, verify the hypothesis, ship the fix, and prevent regressions.

    3 min read
  4. 4

    Images for Performance: Sizes, Formats, Priority, and Preload

    How to ship fast images: responsive sizes, AVIF/WebP, LCP hero strategy, lazy loading, and when preloading helps (or hurts).

    3 min read
  5. 5

    Fonts Without Regret: Fast Loads, No CLS

    How fonts hurt LCP/CLS, when to preload, how font-display works, and practical strategies to avoid layout shift with good typography.

    2 min read
  6. 6

    JavaScript Cost: Hydration, Long Tasks, and Shipping Less JS

    How JS hurts INP and load performance, how to find long tasks, and practical patterns to reduce client JS in modern apps (especially Next.js).

    4 min read
  7. 7

    Caching & CDNs: HTTP Caching That Actually Works

    A practical guide to cache-control, ETag, immutable assets, and CDN strategy to reduce TTFB and speed up repeat visits.

    2 min read
  8. 8

    Rendering Pipeline: Layout, Paint, Composite (and How to Avoid Jank)

    A practical mental model of the browser rendering pipeline and how common coding patterns cause forced reflow, jank, and slow interactions.

    ~16 min
  9. 9

    Third-Party Scripts: Containment Strategies That Keep Pages Fast

    How third-party scripts hurt performance, how to measure the damage, and pragmatic strategies: defer, isolate, audit, and remove.

    2 min read
  10. 10

    Next.js Performance: RSC, Streaming, and Caching Patterns

    How Next.js (App Router) affects performance: server components, client boundaries, streaming, caching, and avoiding accidental JS bloat.

    2 min read
  11. 11

    Measuring Performance: Lighthouse vs RUM (and Setting Budgets)

    How to measure performance like a pro: lab vs field metrics, what to trust, and how to set practical budgets to prevent regressions.

    2 min read
  12. 12

    Performance Recipes: High-ROI Fixes (Before/After Patterns)

    A collection of practical performance fixes with before/after patterns: LCP hero, INP long tasks, CLS shifts, caching, and third-party containment.

    2 min read
  13. 13

    Web Performance Interview Pack: 25 Questions + Best Answers

    High-signal web performance interview questions with crisp answers: Core Web Vitals, caching, rendering, images, fonts, JS cost, and debugging.

    11 min read
  14. 14

    CSS Performance: contain, content-visibility, and Rendering Cost Control

    How to reduce rendering cost with modern CSS tools: containment, content-visibility, and avoiding expensive effects that trigger heavy paint/layout.

    2 min read
  15. 15

    Performance APIs: Web Vitals, Long Tasks, and Real Metrics

    Understand the browser APIs behind performance measurement: PerformanceObserver, long tasks, navigation timing, and capturing Web Vitals in real apps.

    2 min read
  16. 16

    Offline & Service Workers: Caching Without Breaking Users

    A practical introduction to service workers and offline caching strategies, including common pitfalls (stale content, cache invalidation) and when to avoid SWs.

    2 min read