What Is Technical SEO?
Technical SEO refers to the optimisations you make to your website's infrastructure — the server, code and architecture — that help search engines crawl, index and understand your content effectively. It is distinct from on-page SEO (content and keywords) and off-page SEO (backlinks) — it is the foundation that both of those rely on.
If Google cannot access, crawl or render your pages correctly, your content and backlinks will not translate into rankings. Technical SEO fixes remove those barriers.
Crawlability
Crawlability refers to Google's ability to access and follow links on your site. Common crawlability issues include:
- Robots.txt blocking important pages — check your
/robots.txtfile is not accidentally blocking CSS, JavaScript or key content pages. Use our free Robots.txt Generator to create a correctly formatted file. - Noindex tags on pages that should be indexed
- Broken internal links — links pointing to 404 pages waste crawl budget
- Very slow server response times — Google may abandon slow pages mid-crawl
Indexability
A page can be crawlable but still not indexed. Indexability issues include:
- Duplicate content — multiple URLs serving the same content without canonical tags confuses Google about which version to index
- Thin content — pages with very little meaningful content may be excluded from the index
- Canonical tag errors — a self-referencing canonical is good; a canonical pointing to the wrong URL can de-index the right page
- Redirect chains — multiple redirects in sequence can cause indexing delays
Site Speed
Page speed is a confirmed Google ranking factor and affects both desktop and mobile rankings. Key metrics are the Core Web Vitals: LCP (loading), CLS (visual stability) and INP (interactivity). Slow sites rank lower and have higher bounce rates, compounding the ranking disadvantage over time.
HTTPS and Security
Google uses HTTPS as a ranking signal and Chrome flags non-HTTPS sites as "Not Secure". Ensure your entire site runs on HTTPS with a valid SSL certificate and that all internal links and canonical tags use HTTPS URLs — not HTTP. Mixed content (HTTPS page loading HTTP resources) can trigger browser warnings.
Structured Data
Structured data (schema markup) helps Google understand the type and meaning of your content. It does not directly boost rankings but enables rich results that improve click-through rates. Adding JSON-LD schema to key pages is a technical SEO implementation that delivers ongoing traffic benefits.
XML Sitemap
Your XML sitemap should list all indexable pages and be submitted to Google Search Console. Regularly audit it to ensure it contains no redirected or noindexed URLs — submitting those confuses Google's crawlers.
Technical SEO Is the Foundation
Think of technical SEO as the foundation of your house. On-page SEO (content, keywords) is the interior and off-page SEO (backlinks) is the reputation. You can have beautiful interior design and a great reputation, but if the foundation is broken, the house will not stand. Fix technical issues first before investing heavily in content or link building.