Technical SEO & Web Performance: The Foundation Guide

Start with Core Web Vitals, Google's three speed and stability metrics. Aim for Largest Contentful Paint under 2.5 seconds, Interaction to Next Paint under 200 milliseconds, and Cumulative Layout Shift under 0.1. Measure real-world scores in Google Search Console's Core Web Vitals report, then diagnose specific pages with PageSpeed Insights and Chrome's Lighthouse.

Most speed problems come from three sources: oversized images, render-blocking JavaScript, and slow servers. Convert images to WebP or AVIF and lazy-load anything below the fold. Defer non-critical scripts and remove apps you no longer use—on Shopify, every extra app injects code that slows checkout. Serve assets through a CDN so visitors load from a nearby edge, not one origin server.

Crawlability decides what search engines can even reach. Keep a clean XML sitemap submitted in Search Console, and use robots.txt to guide crawlers rather than block them by accident. Watch for the silent killers: pages returning 404 or 500 errors, redirect chains that waste crawl budget, and 'noindex' tags left on important pages after a redesign. Screaming Frog will crawl your whole site and surface these in minutes.

Duplicate content confuses engines about which page to rank. This is common on e-commerce sites where filters and sort parameters create dozens of URLs for one product. Fix it with canonical tags that point every variant back to the primary URL. Pick one domain version—https, with or without www—and 301-redirect the rest so link authority consolidates instead of splitting.

Structured data (Schema markup) is how you speak directly to machines. Adding Product, FAQPage, Article, or Organization schema in JSON-LD tells Google exactly what a page is, which earns rich results—star ratings, prices, FAQ dropdowns—and makes your content easier for AI answer engines to extract and cite. Validate every template with Google's Rich Results Test before shipping.

Mobile is not optional. Google indexes the mobile version of your site first, so if your mobile layout hides content or loads slowly, that's the version being judged. Test responsive behavior on real devices, keep tap targets large enough, and make sure the same content and structured data exist on mobile as on desktop.

Technical SEO is maintenance, not a one-time project. Schedule a monthly check: review Core Web Vitals trends, run a Screaming Frog crawl for new broken links, confirm your sitemap is current, and re-test schema after any theme or app change. A site that stays fast, clean, and machine-readable keeps its rankings and shows up in AI answers long after the initial work is done.