What is Technical SEO?

Technical SEO is the SEO discipline focused on optimising a website's structural, code, and infrastructure aspects to facilitate its crawling and indexing by search engines like Google.

Unlike on-page SEO (which focuses on visible content) or off-page SEO (focused on external links), technical SEO works "behind the scenes": page load speed, URL structure, structured data, JavaScript rendering, HTTP error management, and mobile compatibility.

It is the foundation upon which any successful SEO strategy is built. A site with excellent content but severe technical issues will struggle to rank well.

Fundamental aspects of Technical SEO include:

1. Crawling and Access: Correct configuration of robots.txt, sitemap.xml, and noindex tags to guide bots.
2. Site Architecture: Clear hierarchical structure, semantic URLs, strategic internal links, and a maximum depth of 3 clicks from the homepage.
3. Speed and Performance: Optimisation of Core Web Vitals (LCP, INP, CLS), image compression, CSS/JS minification, and CDN usage.
4. Structured Data: Implementation of Schema.org markup to help Google understand content context.
5. Mobile-first: Responsive site with a good mobile experience, as Google indexes the mobile version.
6. Security: Mandatory HTTPS, security headers, and protection against vulnerabilities.
7. Error Management: Correct handling of 404, 301, 410 codes and avoiding redirect chains.

Technical SEO best practices in 2026 include:

• Comprehensive Audit: Conduct a thorough technical audit using tools like Screaming Frog, Sitebulb, or DeepCrawl every 3-6 months.
• Core Web Vitals: Ensure LCP < 2.5s, INP < 200ms, and CLS < 0.1 for 75% of visits.
• Crawl Budget: For large sites (+10k URLs), manage the crawl budget by blocking low-priority URLs.
• Schema Markup: Implement relevant schemas for your sector (Product, Article, FAQ, HowTo, BreadcrumbList).
• Canonicals: Use canonical tags to prevent duplicate content across URL variations.
• Dynamic Sitemaps: Automatically generate updated XML sitemaps and include them in Search Console.
• JavaScript SEO: If you use SPAs or a lot of JS, ensure Server-Side Rendering (SSR) or prerendering.

An e-commerce site with 50,000 products and typical technical issues: average load time of 5s, JavaScript not rendering correctly, outdated sitemap, and many URLs with parameters generating duplicate content.

Technical SEO intervention:

• Migration to Jamstack architecture with SSR to reduce LCP to 1.2s
• Image optimisation to WebP with lazy-loading → -60% weight
• Implementation of Schema Product on all product pages
• Correct canonicals on URLs with filters
• Dynamic sitemap with category priorities

Result: +120% organic traffic in 6 months and improved Quality Score in Google Ads.