A technical SEO audit is a structured check of everything that decides whether search engines can crawl, render and index your pages: status codes, redirects, canonicals, robots rules, sitemaps, speed, mobile rendering and structured data. Monitoring repeats that check on a schedule, so a bad release or a broken plugin is caught in days, not after traffic falls.
What does a technical SEO audit cover?
Think of five layers, in this order:
- Access: can Googlebot reach the pages? (robots.txt, server errors, login walls, blocked resources)
- Indexing: are the right pages in the index and the wrong ones out? (canonicals,
noindex, duplicates, sitemaps) - Structure: do links and redirects lead to working pages? (broken links, redirect chains, orphan pages, URL patterns)
- Experience: do pages load fast and display well on phones? (Core Web Vitals, mobile rendering)
- Markup: are titles, headings and structured data present and valid?
Fixing layer 1 before layer 5 saves hours, because nothing downstream matters if Google cannot get in.
Why does it matter for SEO?
Content and links only work on a technically sound site. A single wrong noindex or a robots.txt line left over from a staging server removes pages from Google. Technical problems also stay invisible: your site looks fine in a browser while Googlebot sees a redirect loop. A scheduled audit is cheap insurance for a site that changes weekly.
How do you run a technical SEO audit, step by step?
- Start with Search Console. Open Google Search Console and read Page indexing, Sitemaps, Core Web Vitals and the Security and Manual actions pages. Note how many pages are indexed and why others are not (see page indexing report).
- Crawl the site. Screaming Frog’s SEO Spider, free for up to 500 URLs per crawl, shows status codes, titles, canonicals and directives for every page. The free version has no saved crawls, no JavaScript rendering and no Search Console connection. Ahrefs Free (the former Webmaster Tools) runs Site Audit on verified sites with 5,000 crawl credits per project per month and checks 170+ issues, according to Ahrefs. Bing Webmaster Tools has a free site scan too.
- Compare the crawl with the sitemap. Pages in the crawl but missing from the XML sitemap are candidates for addition. URLs in the sitemap that redirect or return errors are bugs.
- Check status codes and redirects. Fix 5xx errors first, then 404s that still get links or traffic, then chains of two or more redirects (see redirects and broken links).
- Check indexing directives. Look for unexpected
noindex, wrong canonicals and pages blocked in robots.txt (see robots.txt and noindex and canonical tags). - Test speed and rendering. Run your top 10 landing pages through PageSpeed Insights, and use URL Inspection in Search Console to see the HTML Google rendered, which matters on JavaScript-heavy sites (see JavaScript SEO).
- Rank problems by impact. Sort the issues by the number of affected URLs and by the traffic of those pages. A missing meta description on 2,000 tag pages matters less than a canonical error on your top product page.
- Fix, then recrawl. Re-run the crawl, then press Validate fix in Search Console where it is offered.
How do you monitor your site between audits?
- Turn on Search Console email alerts. Google emails owners about indexing, security and manual action issues.
- Schedule a crawl. Ahrefs Free can recrawl monthly; paid Screaming Frog supports scheduled crawls. Keep the settings the same each time so results compare.
- Run a site-availability check on your homepage and checkout. Several monitoring services have a free plan, and it alerts you when the site returns errors.
- Review a release checklist. Before any launch or migration, confirm robots.txt, canonicals, redirects and the sitemap on the new version.
- Check the first Monday of each month: indexed pages, Core Web Vitals groups and crawl errors, written down in one sheet (see SEO reporting).
How do you measure whether the audit worked?
Compare three numbers before and 4 to 8 weeks after the fixes: indexed pages (Search Console Page indexing), crawl error counts in your crawler, and clicks to the fixed page groups in the Performance report. Also track the number of URLs with each issue type, which should fall to zero for errors.
What mistakes should you avoid?
- Treating every warning as an error. Tool scores count things like short titles equally with server errors. Fix by impact.
- Auditing once and forgetting. Plugin updates and redesigns re-break things.
- Blocking the crawler in the test. A staging password or firewall rule hides the real picture.
- Trusting the crawler over Google. Search Console shows what Google really sees. Use the crawler to find causes.
- Fixing before backing up. Changing redirects or canonicals in bulk needs a saved list of the old rules.
Where can you learn more?
The free landing page analyzer from Fe/male Switch checks one page quickly: title, meta tags, speed and layout. Next steps: read the page indexing report, then clean up broken links and redirects.