Bfcache: The Free Speed You Lose With One Header
The back/forward cache makes back navigation instant and lifts field metrics for free, unless something blocks it. Blockers from no-store to unload handlers.
Writing
Performance: what we have had to fix
65 write-ups from production, newest first. Each one is a problem hit on a real project and how it was diagnosed and fixed.
Cookie Consent Banners Without CLS or INP Cost
The consent banner is often the worst thing on a page for Core Web Vitals: it shifts layout, blocks the thread and fires every tag on Accept. Making one fast.
A Core Web Vitals Audit Report Engineers Act On: Our Format
Most performance audits are a Lighthouse export with commentary. The format we use instead: field data first, per-metric attribution, prioritised fixes, checks.
INP: Finding the Slow Interaction in Field Data
INP fails in Search Console and the lab shows nothing. How to instrument real users to find which element, event and script is slow, and report it usefully.
generateStaticParams for Hundreds of Routes Without OOM
Prerendering hundreds of pages without a twenty-minute build or an out-of-memory failure: fetch once, tune workers, leave the long tail dynamic, measure it.
LCP Images the Browser Cannot Discover, and the Preload Fix
Why some hero images start loading a second late: CSS backgrounds, JavaScript-inserted images, lazy loading on the wrong element. See the delay and fix it.
Next.js Image Optimisation: sizes, priority, quality and LCP
Getting next/image right for LCP: the sizes attribute most sites get wrong, when to use priority, quality and format trade-offs, and the check that proves it.
Link Prefetching at Scale: When It Hammers Your RSC Endpoint
A page with two hundred links prefetches two hundred routes. How next/link prefetching works, when it becomes a cost, and how to tune lists and mega-menus.
TTFB on Managed Hosting and Edge Functions: Where Time Goes
Time to first byte sets the floor for every metric. Its components from DNS to origin, how to measure each, and what managed hosts and edge platforms get wrong.
WordPress Admin Slow: Autoloaded Options and Transients
The front end is fast, the admin takes eight seconds a page. Where admin time goes: autoloaded options, transients, cron on page load, dashboard widgets, fixes.
Image Handling in WordPress: Sizes, WebP, Lazy Loading, LCP
How WordPress generates, serves and lazy-loads images, where the defaults hurt Core Web Vitals, and the configuration that gets the hero loading fast.
Speed Monitored, Not Checked Once: Why Performance Drifts
A site that was fast at launch is slow a year later and nobody changed the design. The five ways performance drifts and what continuous monitoring looks like.
Why Your Website Should Load in Two Seconds on a Phone
The plain-words case for website speed: what two seconds means, what visitors do at three and four, how Google uses it, and how to check your site in a minute.
Hunting Cumulative Layout Shift: Finding What Moves and Why
A method for tracking down layout shift: reproducing it, reading DevTools shift records, the usual suspects from fonts to widgets, and the fix for each.
Critical CSS and Render-Blocking Resources, Explained
Why a page stays blank while stylesheets and scripts load, what the render-blocking audit means, and the fixes in order of return, from fewer files to inlining.
Mobile-First Performance Testing on a Mid-Range Android
Your laptop is lying about page speed. Why field data is dominated by mid-range phones, how to test on one or emulate it honestly, and what changes.
Cache Components in Next.js 16 for a Business Website
How Cache Components change caching for a marketing site: what use cache does, how cacheLife maps to page types, dynamic edges and prerender mistakes.
Auditing an Inherited WordPress Theme: The 90-Minute Method
A repeatable ninety-minute audit for a WordPress theme someone else built: what to read first, what to grep for, and how to write up fix or replace.
Faster WooCommerce Checkout: Scripts, Fragments, Cart API
The checkout is the page a cache cannot help. Where WooCommerce checkout time goes, the scripts and cart fragments that slow it, and the fixes that work.
Images That Take Ten Seconds: Compressing a Whole Site
How to compress every image on an existing website: finding the heavy ones, choosing formats and sizes, batch tools, and keeping new uploads small.
WordPress Caching Layers: Page, Object, Opcode and CDN
The four caching layers a WordPress site can have, what each speeds up, which you need for a brochure site versus a store, and the setups that make it slower.
Lighthouse Green, Search Console Red: Which CWV to Trust
Why PageSpeed says your site is fast while Search Console fails it on Core Web Vitals, which data Google uses, and how to audit against the numbers that count.
FCP Regression After Enabling React Compiler in Next.js 16
First Contentful Paint regressed after turning on reactCompiler in Next.js 16? Here is why the runtime cache pushes paint and the boundary fix that recovers it.
INP Regression After Adding Cloudflare Turnstile Widget Fix
INP score tanked on mobile after adding the Cloudflare Turnstile widget? Here is why the embed script blocks interaction and the lazy-load fix that works.
Next.js 16 Link Prefetch Hammering Your RSC Endpoint
Next.js 16 Link prefetch flooding your RSC endpoint on hover? Here is why the new heuristic fires too eagerly and the prefetch={false} fix that holds.
Open Graph Image Stale After Vercel Deploy: Cache Fix
Open Graph image showing the old version after deploy on Vercel? Here is why Facebook, Slack, and LinkedIn keep the stale image and the cache-bust that works.
Intercom Widget INP Regression on Mobile: The Fix
Intercom widget tanking INP on mobile after the May launcher update? Here is why the script blocks the main thread and the lazy-mount fix that holds up.
Vercel Image Optimization 402 Quota Exceeded Production Fix
Vercel Image Optimization returning 402 quota exceeded in production? Here is what triggers the cap and the config fix that stops the bill from rising.
Next.js 16 Link Prefetch Flooding Vercel Edge Requests
Next.js 16 Link prefetch is blowing through your Vercel Edge request budget? Here is why hover-prefetch fires twice and the config that brings it back to sane.
LCP Regression After Cloudflare Polish WebP on Next.js
LCP doubled after enabling Cloudflare Polish on a Next.js site? Here is why double-encoding hurts and the bypass rule that brings LCP back under 2 seconds.
INP Regression After Enabling React Compiler in Next.js 16
INP regression after enabling React Compiler on Next.js 16? Here is which memoised event callbacks blow the interaction budget and how to roll back safely.
React Compiler INP Regression in Production: Fix
React Compiler enabled on Next.js 16 and field INP regressed past 200ms? Here is why auto-memoisation pushes work post-commit and the scoped fix that lands.
CLS From Trustpilot Widget Late Load on Product Pages
Trustpilot widget pushing CLS over 0.1 on product pages? Here is the reserved-space pattern and lazy load fix that stops the layout shift on mobile devices.
LCP Regression After CSS Container Queries Migration
Migrated to CSS container queries and watched LCP jump 800ms in field data. Here is why the hero image stops being a priority paint and how to fix it.
INP Regression After React 19.2 useTransition Migration
INP field data spiking after wrapping filter handlers in useTransition? Here is why React 19.2 transitions can make INP worse and the pattern that fixes it.
Next.js 16 PPR Static Shell Flashing on Dynamic Routes
Next.js 16 PPR shell flashing skeleton before dynamic content paints? Here is why the prerender slot leaks and the Suspense boundary fix that stops it.
Speculation Rules API Inflating GA4 Page Views Fix
GA4 page views jumped 20-40% after enabling Speculation Rules prerendering? Why prerendered pages double-count, and the prerenderingchange fix.
LCP CSS Background Image Not Discovered by Browser Fix
Your hero background image is the LCP but the browser only finds it after CSSOM parsing? Why fetchpriority does not help, and the preload that does.
Cloudflare Rocket Loader Breaking Next.js INP Scores Fix
Cloudflare Rocket Loader tanking INP on a Next.js site? Here is why it delays React hydration on mobile and the page rule that restores interactivity.
Next.js 16 Image Qualities Not Configured Error Fix
Next.js 16 throwing an unconfigured qualities error or blurry images after upgrade? Here is why images.qualities now defaults to 75 and the config fix.
next/script afterInteractive Blocking INP on Mobile
next/script strategy='afterInteractive' still pushing INP past 500ms on mobile? Here is the lazyOnload, worker, and onLoad fix that drops it back under 200ms.
Next.js cacheComponents Mapbox Crash on Route Reappear: Fix
Next.js cacheComponents can break Mapbox, video players, and other imperative widgets on back navigation. Here is the fix path I trust in production today.
TTFB Spike from Vercel Middleware Geolocation Lookup
Vercel middleware doing geo redirects spiking TTFB to 800ms? Here is the runtime, header, and edge config fix that cuts it back under 100ms.
INP Regression From Sentry Session Replay 9 on Mobile
Sentry Session Replay 9 tanking INP on mobile after the upgrade? See what changed in the rrweb sampler and the config fix that pulls INP back under 200ms.
Next.js bfcache Not Restoring Page on Back Navigation Fix
Next.js page failing back/forward cache and re-rendering on browser back? Most causes are unload listeners, open WebSockets, or Cache-Control no-store.
Long Animation Frames API for Debugging INP in Production
Debugging INP regressions in 2026? Wire the Long Animation Frames API to capture the exact slow handler in real users with a working PerformanceObserver.
INP Field Data Worse Than Lighthouse Lab Score Fix
Lighthouse INP score is green but CrUX field data is failing pages in Search Console? Close the lab-vs-real-user INP gap with focused attribution fixes.
CLS From Skeleton Loaders in Suspense Fallback Fix
Cumulative Layout Shift spiking from Suspense skeleton loaders in Next.js 16? Match the skeleton dimensions to real content with a working CSS pattern.
Next.js 16 ISR Memory Leak: Off-Heap Buffer Growth
Next.js 16.2.4 ISR memory leak symptoms usually show up as rising external and arrayBuffers usage. Here is the diagnosis path I trust on self-hosted apps.
PageSpeed LCP Different From Field Data Fix Guide
PageSpeed Insights LCP score different from CrUX field data? Fix the lab vs real-user gap with throttling, viewport, and resource priority hints.
next/image priority Not Preloading Hero: LCP Fix
next/image with priority not generating a preload link and tanking your hero LCP score? Fix the missing preload hint and PPR boundary issue with code.
Vercel Speed Insights No Data After Next.js 16: Fix
Vercel Speed Insights showing no data after Next.js 16 upgrade? Fix the missing beacon, CSP block, and the SpeedInsights component placement with code.
Cookie Consent Banner CLS Fix: Stop the Layout Shift
Cookie consent banner tanking your CLS score and Core Web Vitals on first paint? Fix the late-injected banner, reserved space, and animation timing in code.
Next.js 16 Image priority Deprecated: Real LCP Fix
Next.js 16 deprecated the priority prop on next/image. Migrate to preload, fix the LCP regression, and stop accidentally preloading every product hero image.
INP Mobile Regression from React Hydration Delay Fix
INP score worse on mobile than desktop after a React deploy? Hydration is blocking the main thread. Fix it with code splitting and Suspense streaming.
LCP Preload Hint Picking the Wrong Image: Real Fix
LCP regressed because the browser preloads the wrong image with next/image priority? Fix fetchpriority, srcset, and preload candidate selection with code.
next/font CLS Layout Shift in Next.js 16: Real Fix
next/font causing CLS layout shift in Next.js 16 after the upgrade? Fix font fallback metrics, size-adjust, and display swap settings with working code.
Technical SEO Audit Checklist for 2026
A practical technical SEO audit checklist for 2026 covering crawlability, indexation, rendering, internal links, structured data, and Core Web Vitals.
WooCommerce Product Filters Slow on Large Catalogs: Fix
WooCommerce product filters slow on 5,000+ products? How to speed up layered navigation, attribute queries, counts and archive pages without guesswork.
WordPress Admin Slow? Check Autoloaded Options First
WordPress admin taking 3 to 10 seconds per page load? Oversized autoloaded options are the most common cause. Here is how to find and fix them safely.
Next.js App Router Render-Blocking CSS Fix
Next.js App Router render-blocking CSS can crush LCP when globals and library styles leak into initial chunks. Here is the fix I use on production builds.
INP Regression from GTM Third-Party Tags in 2026
INP score regressing above 200ms after adding Google Tag Manager tags? Here is how to diagnose the blocking tag and fix it with working code.
CLS Spike from next/font Local Fallback in Next.js 16
CLS regression spiking from next/font fallback after upgrading to Next.js 16? Here is the root cause and adjustFontFallback fix with working code.
WordPress Performance: How I Cut Load Times by 60%
A step-by-step guide to optimizing WordPress performance. Caching, image optimization, CDN setup, and database cleanup that delivered 60% faster load times.
Core Web Vitals in 2026: The Complete Developer Guide
Everything developers need to know about Core Web Vitals in 2026. LCP, INP, CLS explained with real-world fixes and measurement strategies.
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