Technical SEO

The health checks that let search engines crawl and index a site properly: status codes, redirects, canonicals, sitemaps, internal links and speed.

2 min read · updated 24 September 2026

Technical SEO is making sure nothing about how the site is built gets in the way of search engines crawling and indexing it. You rarely see these problems by browsing your own site, which is why a crawler-based site audit finds so many.

Status codes

Every page answers with a status code:

• 200 means the page loaded.
• 301 means it has moved permanently. Use it when a page's address changes, so visitors and its search standing go to the new address.
• 302 means a temporary move. Using it for a permanent change is a common mistake.
• 404 means not found. A few are normal; internal links pointing at 404s are not.
• 5xx means a server error. Repeated server errors make crawlers visit less often.

Broken links and redirect chains

Internal links should point straight at live pages. A link that goes through one or more redirects before reaching the page wastes crawl time and slows visitors down. Update the link to the final address.

Duplicate content and canonicals

The same page is often reachable at several addresses: with and without www, with and without a trailing slash, with tracking parameters on the end. Pick one version of the site and redirect the others to it, and add a canonical tag to each page naming its main address.

Indexing controls

• noindex on a page keeps it out of search results. Useful for thank-you pages and internal search results, harmful when left on a service page.
• robots.txt stops crawling of whole sections. Do not use it to hide a page from results; a blocked page can still be listed if other sites link to it.

XML sitemap

List every page you want indexed, keep it up to date automatically, and reference it at the bottom of robots.txt. Leave out redirects, errors and pages marked noindex.

Internal linking and click depth

Important pages should be reachable within about three clicks of the home page. Pages buried deep, or with no internal links at all (orphans), are crawled less and tend to rank worse. The internal linking report in Site Audit lists orphan pages, click depth and weak anchor text.

HTTPS and mixed content

The whole site should load over HTTPS, and HTTP addresses should redirect to it. An HTTPS page that loads images or scripts over plain HTTP ("mixed content") shows browser warnings.

Speed and Core Web Vitals

Google measures real visitors' experience with three Core Web Vitals:

• Largest Contentful Paint (LCP): how quickly the main content appears. Aim for under 2.5 seconds.
• Interaction to Next Paint (INP): how quickly the page responds to taps and clicks.
• Cumulative Layout Shift (CLS): how much the layout jumps around while loading.

The usual fixes on small business sites are compressing images, removing unused plugins and scripts, and choosing better hosting.

Server logs

Your web server records every request, including every visit from Googlebot and AI crawlers. Log files show which pages crawlers actually spend time on, and whether they keep hitting errors. Log file analysis reads them for you.