Page speed for B2B tech websites: a 2026 checklist

Page speed is one of the few marketing levers where the work is unambiguous and the results are measurable within a week. Yet most B2B tech websites we audit are bleeding speed in the same predictable places. Hero images that ship a 2MB PNG when a 120KB WebP would do. Five marketing tags that block rendering before the page is even visible. A web font stack that pulls 600KB before the first character paints.

This is the checklist we run through when we audit or rebuild a B2B tech site. It is the work that actually moves the numbers, in roughly the order we tackle it.

Start with the right measurement tools

Before you change anything, get a baseline. We use four tools in combination because each shows you something the others miss.

• PageSpeed Insights: synthetic Lighthouse scores plus real-user (CrUX) data for the URL if available. The CrUX data is what Google actually ranks on.
• GTmetrix or WebPageTest: detailed waterfall showing exactly which resources are blocking what.
• Chrome DevTools Performance panel: for diagnosing JavaScript execution and rendering issues.
• Search Console Core Web Vitals report: real-world performance across your whole site, not just a single URL.

Test on a throttled mobile connection (4G or “Slow 4G” in DevTools), not your fibre office connection. The buyer comparing providers on their phone in a meeting room is the user who matters.

Images: the biggest single win on most sites

On almost every B2B tech site we audit, images are the largest, most easily fixed problem.

• Convert to WebP or AVIF. Both are widely supported. WebP typically saves 25 to 35 per cent over JPEG, AVIF more.
• Serve responsive images with srcset and sizes. Do not ship a 2400px hero image to a 390px mobile viewport.
• Lazy-load below-the-fold images with loading="lazy". Eager-load the LCP image (usually the hero) with fetchpriority="high".
• Specify width and height attributes to prevent layout shift.
• Compress aggressively. We use Squoosh, ImageOptim or a build pipeline like Sharp. A B2B site rarely needs an image above 200KB.

The single image change that helps Core Web Vitals most is preloading the LCP image, because LCP is now scored against the largest image painted in the viewport.

Fonts: where good intentions go wrong

Custom fonts are the second most common performance drag on tech sites, particularly when a brand uses three weights of one font and two weights of another.

• Self-host fonts rather than pulling from Google Fonts. The privacy benefit (no third-party request, GDPR friendlier) is a bonus.
• Subset fonts to the characters you actually use. Latin only is fine for most UK B2B sites.
• Preload the fonts the LCP element uses with <link rel="preload" as="font" type="font/woff2" crossorigin>.
• Use font-display: swap so text is visible during the font load. The flash of unstyled text is preferable to the flash of invisible text.
• Limit the weights you load. Two weights (regular and bold) cover most needs. We see sites loading nine weights and using three.

Scripts: the silent killer

JavaScript is where B2B tech sites quietly accumulate performance debt. Every marketing tool that gets added (chat widget, heatmap tool, A/B testing platform, third-party form, analytics, two retargeting pixels, a personalisation tool) ships its own script. Most are not optimised for performance.

The audit we run:

• List every script firing on the page. There will be more than you think.
• Categorise each one as critical, useful or “we forgot we had this”.
• Defer or remove anything not strictly required for first paint.
• Move analytics and tag manager loading to fire after page interactive, not on page load.
• Self-host critical scripts where possible, particularly Google Tag Manager, to avoid third-party DNS lookups.
• Use a tag management policy. Marketing teams add tags forever and never remove them. Quarterly cleanup matters.

A common pattern: a heatmap tool that has not been logged into for 18 months is still firing 80KB of JavaScript on every page load. Find these and remove them.

Hosting and CDN: the foundation

You cannot beat physics. If your origin server takes 800ms to respond, no amount of front-end optimisation will get you a fast site.

• Use a managed host that suits your platform. WP Engine, Kinsta or Pressable for WordPress. Vercel or Netlify for headless and static.
• Put a CDN in front of everything. Cloudflare is the default for most of our clients because it is excellent and the free tier is genuinely generous.
• Enable Brotli compression. It is better than gzip and now widely supported.
• Configure cache headers properly. Static assets (images, fonts, CSS, JS) should have long cache lifetimes with versioned URLs.
• HTTP/2 or HTTP/3 should be on by default. If you are still on HTTP/1.1, your host is the issue.

For sites serving an international audience, a CDN with edge caching dramatically improves time to first byte for visitors outside the origin region.

CSS: render-blocking by default

CSS blocks rendering until it is parsed. Every kilobyte matters.

• Inline critical CSS (the styles needed for above-the-fold content) and defer the rest.
• Remove unused CSS. Tools like PurgeCSS or the coverage tab in DevTools find this. We routinely strip 60 to 70 per cent of CSS from inherited sites.
• Avoid CSS frameworks that ship a full Bootstrap or full Tailwind without purging. A Tailwind build that has not been purged ships hundreds of kilobytes of unused class definitions.
• Watch for blocking third-party stylesheets (font services, embedded widgets).

Core Web Vitals specifically

Google grades pages on three Core Web Vitals: LCP (Largest Contentful Paint), INP (Interaction to Next Paint, which replaced FID in 2024) and CLS (Cumulative Layout Shift). Each has a “good” threshold.

• LCP under 2.5 seconds: optimise the LCP image, preload it, reduce server response time.
• INP under 200 milliseconds: reduce JavaScript execution on interaction, break up long tasks, keep main-thread work small.
• CLS under 0.1: reserve space for images, ads and embeds. Avoid injecting content above existing content.

We unpack the 2026 picture in our Core Web Vitals 2026 guide. The relationship between speed and search ranking is also covered in our technical SEO audit checklist for tech.

Build tooling and bundling

For sites with a custom front-end, the build pipeline matters.

• Tree-shake aggressively. Most JavaScript bundles ship code that is never used.
• Code-split by route. Do not ship the careers page bundle to the homepage visitor.
• Use modern image components (Astro’s <Image>, Next.js <Image> or equivalent) that handle responsive sizing and format conversion automatically.
• Avoid client-side rendering for content that does not need it. Static or server-rendered HTML is faster, more SEO-friendly and more accessible.

This is one of the reasons we increasingly favour Astro for B2B tech sites where performance is a real competitive lever, as we discuss in the case for hand-coded websites.

What good looks like

For a B2B tech site, our targets are:

• LCP under 2.0 seconds on 4G mobile
• INP under 150ms
• CLS under 0.05
• Total page weight under 500KB on the homepage
• Lighthouse performance score above 90 on mobile

These are achievable on WordPress, headless or hand-coded stacks. They are not achievable if you have not done the work in this checklist. They also matter for paid media, as we discuss in landing page CRO for paid traffic, because Google Ads quality scores reward fast pages. Slow pages also undermine even well-designed CTAs, which we explored in why “request a quote” CTAs fail.

Where to start

If you have not benchmarked recently, run PageSpeed Insights on your top three pages (homepage, top service page, top blog post) and screenshot the results. Pick the worst offender and start at the top of this list. Most sites can take a 30 per cent improvement in LCP within a sprint by fixing images and fonts alone.

If page speed is hurting your conversion or rankings and you want a fresh pair of eyes on the build, tell us about it. Our web design and SEO teams work together on this kind of remediation, and we are usually able to flag the biggest wins on a 30-minute call.