Technical SEO Checklist: The Essential Checks for a Healthy Website

A technical SEO checklist covers the behind-the-scenes checks that let search engines find, crawl, render and index your pages, and let visitors use them comfortably. The essentials are crawlability, indexation control, site architecture, page speed and Core Web Vitals, mobile usability, HTTPS, structured data and clean redirects. If these are broken, even excellent pages can sit unseen while weaker competitors rank above you.

Why technical SEO comes first

Content and links get most of the attention in SEO, but they sit on top of a technical foundation. If Google cannot reach a page, cannot render its content, or is told not to index it, nothing else you do for that page matters. Technical problems also tend to be silent. A stray “noindex” tag or a broken redirect after a website update rarely announces itself. You just notice, weeks later, that enquiries have dropped.

For a small or medium business site, most technical SEO comes down to a set of repeatable checks. Work through them properly once, fix what you find, then revisit them on a schedule and after any significant change to the site.

You will need two free tools for most of what follows: Google Search Console, which shows how Google sees your site, and a crawler that walks through your pages the way a search engine does. Several desktop crawlers offer free versions that are sufficient for smaller sites.

Can search engines reach your pages?

Crawling is how search engines discover content, by following links and reading sitemaps. Anything that blocks that process, or wastes it on pages nobody needs, is worth fixing.

Robots.txt

Your robots.txt file, found at the root of your domain, tells crawlers which areas they may visit. Check that it does not block important sections, stylesheets or scripts that pages need to render. A common mistake is a “Disallow: /” line left over from a staging site, which asks crawlers to stay away from everything. Bear in mind that robots.txt controls crawling rather than indexing. A blocked URL can still appear in results if other sites link to it.

XML sitemap

An XML sitemap lists the URLs you want search engines to know about. It should contain only live, indexable, canonical pages that return a 200 status. Remove redirected URLs, error pages and anything marked noindex. Submit the sitemap in Search Console and reference it in robots.txt.

Internal links and orphan pages

Search engines mainly discover pages through links. A page with no internal links pointing to it, often called an orphan page, may be crawled rarely or not at all. Compare the URLs in your sitemap with the URLs your crawler finds by following links. Anything in the sitemap that cannot be reached by a link needs connecting.

Crawl waste

Filters, sort orders, session parameters and calendar archives can generate huge numbers of near-identical URLs. On larger sites, especially online shops, this can soak up crawling attention that would be better spent on important pages. Control it with sensible linking, canonical tags and, where appropriate, robots.txt rules. Faceted navigation on shops is a specialist area in its own right, and a common focus of ecommerce SEO work.

Are the right pages in Google’s index?

Being crawled is not the same as being indexed. The Page indexing report in Search Console shows which URLs are indexed and, more usefully, why others are not.

• Check for accidental noindex tags. A meta robots noindex tag or an X-Robots-Tag header on an important page removes it from results. Website builders and SEO plugins sometimes apply these to whole sections by default.
• Review canonical tags. Every indexable page should have a self-referencing canonical, or a canonical pointing to the preferred version if it is a duplicate. We often find canonicals pointing to the wrong page, to redirected URLs or to the homepage, and each one can keep the right page out of results.
• Look at “Crawled – currently not indexed” and “Discovered – currently not indexed”. These often signal that Google sees a page as low value or duplicative. The fix is usually better or consolidated content rather than a technical tweak.
• Search for duplicates. Check that only one version of your site resolves: with or without “www”, and HTTPS only. The others should redirect permanently to the preferred version.
• Spot-check with the URL Inspection tool. For your most important pages, inspect the live URL to confirm Google can fetch it, sees the right canonical and can render the content.

Site architecture and URLs

A clear structure helps visitors find what they need and helps search engines understand how your pages relate.

• Keep important pages close to the homepage. Key service, category and product pages should be reachable within a few clicks.
• Use logical, readable URLs. Short, lowercase, hyphenated URLs that describe the page, such as /services/boiler-repair/, are easier for everyone to understand than strings of IDs and parameters.
• Group related content. Folders and menus should reflect how your business and topics are organised.
• Use breadcrumbs. Breadcrumb trails show where a page sits in the hierarchy and add useful internal links.
• Avoid changing URLs without a reason. Every URL change needs a redirect and risks temporary disruption.

Architecture and internal linking go together. The pages you link to most often, and the words you use in those links, tell search engines which pages you consider most important.

Page speed and Core Web Vitals

Core Web Vitals are Google’s metrics for real-world loading, responsiveness and visual stability. They are measured from actual visits in Chrome, and Google assesses them at the 75th percentile of page loads. The “good” thresholds are set out below.

Check the Core Web Vitals report in Search Console for field data, and use PageSpeed Insights to diagnose individual templates. Fixes that usually help include properly sized and compressed images in modern formats, lazy loading for images below the fold (but not the main hero image), removing unused plugins and tracking scripts, setting width and height on images and embeds, and using caching and a content delivery network.

Speed matters for users as much as for rankings, since a slow, jumpy page loses people wherever it ranks. If your scores are poor across the board, a focused website speed optimisation project is often more efficient than piecemeal fixes.

Mobile usability

Google uses the mobile version of your site for indexing and ranking, an approach known as mobile-first indexing. If something is missing or broken on your mobile pages, Google treats it as missing.

• Make sure the mobile version contains the same important content, headings, internal links and structured data as the desktop version.
• Check that text is readable without zooming and that buttons and links are comfortable to tap.
• Avoid intrusive pop-ups that cover the main content as soon as someone arrives.
• Test forms, menus and checkout on real phones as well as in a resized desktop browser.

Security, status codes and redirects

HTTPS everywhere

Your whole site should load over HTTPS with a valid certificate. Check for “mixed content”, where a secure page loads images or scripts over plain HTTP, and make sure every HTTP URL redirects to its HTTPS equivalent.

Status codes

Your crawler will report the status code each URL returns. Pages you want indexed should return 200. Pages that have moved should return 301 (permanent redirect). Pages that are gone should return 404 or 410. Watch for “soft 404s”, where an error or empty page returns 200, and for 5xx server errors, which suggest hosting or application problems.

Redirect hygiene

• Replace redirect chains (A to B to C) with a single hop from A to C.
• Fix redirect loops immediately.
• Update internal links so they point directly to the final URL rather than relying on redirects.
• When you remove a page, redirect it to the closest equivalent rather than sending everything to the homepage.

Redirects matter most during a website redesign or platform migration, which is when the most serious technical SEO problems tend to occur.

Structured data and on-page technical elements

Structured data, usually added as JSON-LD, describes your content in a format machines can read reliably. It can make pages eligible for rich results and helps search engines and AI systems understand what your business sells.

• Organization or LocalBusiness on the homepage or contact page, with name, address, logo and contact details matching what is shown on the page.
• Product with offers and availability for ecommerce product pages.
• Article or BlogPosting for editorial content, with author and date information.
• BreadcrumbList to reflect your site hierarchy.

Validate markup with Google’s Rich Results Test and check the enhancement reports in Search Console. Only mark up content that is visible on the page.

While you are on each template, check the basics too: a unique, descriptive title tag; a meta description that summarises the page; one clear main heading; logical heading order; descriptive alt text on meaningful images; and the correct language declaration. If you run a bilingual Welsh and English website, hreflang annotations tell search engines which language version to show to whom.

Your technical SEO checklist

Print this out or copy it into a spreadsheet. Most items take minutes to check, though fixing them can take longer.

How to run a technical audit in order

Doing the checks in a sensible sequence avoids wasted effort, because some problems hide others.

1. Gather your data. Confirm you have Search Console access for the correct property and run a full crawl of the site.
2. Fix access problems first. Robots.txt blocks, sitewide noindex tags, server errors and HTTPS issues come before everything else, because they can affect the entire site.
3. Resolve duplication and canonicalisation. Make sure each piece of content has one preferred URL and that all versions point to it.
4. Clean up status codes and redirects. Fix broken internal links, chains and soft 404s.
5. Improve performance on key templates. Focus on the templates that drive revenue, such as service, category or product pages, rather than chasing a perfect score on every URL.
6. Check mobile parity and usability. Confirm nothing important is missing or awkward on phones.
7. Add or correct structured data. Start with organisation details, then page-type markup.
8. Document and monitor. Record what you changed and when, so you can link changes to later movements in Search Console.

For prioritisation, weigh each issue by how many pages it affects and how important those pages are commercially. A broken canonical on one blog post can wait; a noindex on your main service template cannot.

Building checks into your routine

Technical SEO never stays fixed for long. Plugins update, editors add pages and third-party scripts creep in. A practical rhythm for most small businesses is a quick monthly look at Search Console’s indexing and Core Web Vitals reports, a full crawl every quarter, and a thorough check before and after any redesign, migration or platform change.

A confident site owner can handle many of the checks above. Others, such as diagnosing JavaScript rendering, untangling years of redirects or improving INP on a heavy theme, usually need a developer. When we run a technical SEO audit, the output is a short, ranked list your developers can work through, with the site-wide problems at the top.

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