Technical SEO Checklist - The Foundations That Actually Matter

Great content and links do not help if search engines cannot crawl, render and index your pages properly. Technical SEO is the layer that makes everything else work. It is not glamorous, but it is where a surprising number of ranking problems actually live.

This checklist walks through the foundations in roughly the order they matter. Start at the top. There is little point obsessing over Core Web Vitals if half your important pages are blocked from being indexed in the first place.

1. Crawlability - can search engines reach your pages

Crawling is step one. If a search engine cannot find or access a page, nothing else applies.

• Check your robots.txt file at yoursite.com/robots.txt. Make sure it is not accidentally blocking important sections. A stray Disallow: / can hide an entire site.
• Confirm important pages are reachable through internal links. Pages with no links pointing to them (orphan pages) are hard to discover.
• Run a crawl with a tool like Screaming Frog or Sitebulb to see what a bot sees, including broken links, redirect chains and blocked resources.
• Make sure CSS and JavaScript are not blocked, since Google needs them to render pages correctly.

2. Indexation - are the right pages indexed

Crawling lets engines see a page; indexing is whether they store it for results. You want your valuable pages indexed and your low-value or duplicate pages kept out.

• Use the site:yoursite.com search and Search Console's Pages report to compare what is indexed against what should be.
• Check for accidental noindex tags on pages that should rank. This is one of the most common and damaging technical mistakes.
• Deliberately noindex thin or utility pages such as internal search results, tag archives with no value, and cart or checkout pages.
• Review the Search Console reasons for excluded pages and fix anything labelled as crawled or discovered but not indexed where the page genuinely matters.

3. XML sitemaps

A sitemap is a list of the URLs you want search engines to know about. It does not guarantee indexing, but it helps discovery, especially on large sites.

• Generate an XML sitemap (most SEO plugins and platforms do this automatically) and submit it in Search Console.
• Include only canonical, indexable, 200-status URLs. Do not list redirected, noindexed or broken pages.
• Keep it current so it reflects new and removed content.

4. Site architecture and internal linking

How your pages connect shapes both crawling and how authority flows through the site.

• Aim for a shallow, logical structure where important pages are only a few clicks from the homepage.
• Group related content into clear sections or topic clusters.
• Use descriptive, keyword-aware internal links between related pages. Internal linking is one of the most underused levers in SEO.
• Fix orphan pages by linking to them from relevant content.
• Use descriptive, readable URLs and avoid deep, cluttered paths.

5. Canonicalisation - handling duplicate content

Duplicate or near-duplicate URLs confuse engines about which version to rank. Canonical tags tell them the preferred version.

• Set a self-referencing canonical tag on standard pages.
• Use canonicals to consolidate variations such as URLs with tracking parameters, sort orders, or printer-friendly versions.
• Make sure your site resolves to a single version. Pick HTTP or HTTPS, and www or non-www, and redirect the rest with 301s so you are not splitting signals across four versions of the same address.
• Watch for conflicting signals, such as a canonical pointing to a noindexed page.

6. HTTPS and security

HTTPS has been a baseline expectation for years and is a lightweight ranking signal.

• Serve the whole site over HTTPS with a valid certificate.
• Redirect all HTTP requests to HTTPS with 301s.
• Fix mixed-content warnings where a secure page loads insecure resources.

7. Mobile usability

Google uses mobile-first indexing, meaning it predominantly uses the mobile version of your site for ranking and indexing.

• Use a responsive design that adapts to screen size.
• Make sure the mobile version contains the same important content and structured data as the desktop version. Do not hide key content on mobile.
• Check tap targets, font sizes and that nothing requires horizontal scrolling.
• Test real pages on real devices, not just in a desktop browser window.

8. Core Web Vitals and page speed

Core Web Vitals are Google's set of user-experience metrics covering loading, interactivity and visual stability. They form part of the page experience signals.

• Largest Contentful Paint (LCP) measures loading. Aim for 2.5 seconds or less.
• Interaction to Next Paint (INP) measures responsiveness. Aim for 200 milliseconds or less. INP replaced First Input Delay in March 2024.
• Cumulative Layout Shift (CLS) measures visual stability. Aim for 0.1 or less.
• Diagnose with PageSpeed Insights and the Core Web Vitals report in Search Console, prioritising field data from real users where available.
• Common wins include optimising images, reducing render-blocking scripts, and reserving space for elements so the layout does not jump.

9. Structured data

Structured data (schema markup) helps engines understand your content and can make pages eligible for rich results.

• Add relevant types such as Organization, Article, Product and Breadcrumb.
• Use JSON-LD, which Google recommends.
• Validate with the Rich Results Test and monitor the Enhancements reports in Search Console.

10. Common technical issues to sweep for

Once the foundations are sound, run a regular audit for the recurring problems that creep in over time.

• Broken internal and external links (404s).
• Long redirect chains and redirect loops.
• Duplicate or missing title tags and meta descriptions.
• Soft 404s, where a missing page returns a 200 status instead of a 404.
• Pages that are slow to render due to heavy third-party scripts.
• Hreflang errors on multilingual or multi-region sites.

How to prioritise

If you only have limited time, fix anything that blocks crawling or indexing first, because those issues stop pages ranking at all. Then tidy canonicals and redirects, confirm mobile and HTTPS are solid, and finally work on Core Web Vitals and structured data, which refine and enhance rather than unblock.

Technical SEO is not a one-off task. Sites change, plugins update, and new content introduces new issues. A scheduled crawl and a monthly look at Search Console will catch most problems before they cost you traffic.

If you want a thorough technical audit and a clear, prioritised plan to act on, Control Tower can review your site and identify exactly what is holding it back.