A technical SEO audit is the diagnostic process every good SEO strategy should start with. Before you write a single word of new content or chase a single backlink, you need to know whether Google can actually access, understand, and rank your website properly. Without an audit, you’re guessing. With one, you have a clear picture of exactly what’s working, what isn’t, and where to focus your energy first.
What Is a Technical SEO Audit?
A technical SEO audit is a structured review of your website’s technical health from a search engine’s perspective. It looks at how crawlers interact with your site — whether they can find your pages, whether those pages are being indexed correctly, how fast they load, how they perform on mobile, and dozens of other factors that influence where your site appears in search results. It’s specifically about the infrastructure of your website — the stuff underneath the content. Done properly, it surfaces issues that might be silently suppressing your rankings.
Why You Need One Before Anything Else
Here’s a scenario that comes up more than you’d think. A business invests months producing excellent blog content. They’ve targeted good keywords, written genuinely useful articles, and earned quality backlinks. But rankings barely move. Nine times out of ten, the culprit is a technical issue. A robots.txt misconfiguration quietly blocking sections of the site. A canonical tag pointing in the wrong direction, splitting authority across duplicate pages. A site scoring so poorly on Core Web Vitals that it’s deprioritised before it gets the chance to compete. Think of a technical audit as the structural survey you’d commission before renovating a house — not glamorous, but essential.
How to Do a Technical SEO Audit: Step by Step
Step 1: Start with Google Search Console
Google Search Console is free and gives you information straight from Google about how it sees your website. In the Coverage report, you’ll find which pages Google has indexed, which it’s excluded, and which have errors. Also check the Core Web Vitals report — any pages in the “Poor” category should be treated as a priority. For issues with crawling, the crawl errors guide walks you through how to address each type.
Step 2: Crawl Your Site
Run a full crawl using a dedicated tool. The most widely used are Screaming Frog (free up to 500 URLs), Sitebulb, or the site audit tools built into Ahrefs or Semrush. A crawl tool visits every page on your site — just like Googlebot would — and returns a detailed report: broken links, duplicate title tags, redirect chains, thin content, images without alt text. Screaming Frog is also invaluable for finding broken links across your entire site.
Step 3: Audit Your Indexation
Do a sanity check on how many of your pages Google is actually indexing. Type site:yourdomain.com into Google. Compare the result count to the number of pages your crawl tool found. A significant mismatch is a red flag that pages are being blocked, or that Google is finding many pages it doesn’t think are worth indexing.
Step 4: Check Your Robots.txt and Sitemap
Your robots.txt file lives at yourdomain.com/robots.txt. Read through it carefully for any Disallow rules that might accidentally block pages you want Google to crawl. After a site migration, outdated robots.txt rules are one of the most common causes of sudden traffic drops. For sitemaps, read our detailed guide on XML sitemaps.
Step 5: Assess Page Speed and Core Web Vitals
Run your key pages through Google’s PageSpeed Insights. This gives you Core Web Vitals scores along with specific recommendations. Focus on your most important pages first: homepage, main service pages, and highest-traffic blog posts. See our full guide on how to improve page speed for SEO for actionable fixes.
Step 6: Check Mobile Usability
Google’s Mobile Usability report in Search Console flags specific pages with mobile issues. Given that Google uses the mobile version of your site as its primary version for indexing, these issues directly affect your rankings.
Step 7: Review Site Structure and Internal Linking
Map out your site structure. Are your most important pages reachable within two or three clicks from the homepage? Are there orphaned pages with no internal links pointing to them? Internal links are how PageRank flows through your site — a deliberate internal linking strategy is one of the highest-leverage actions available to you.
Step 8: Look for Duplicate Content Issues
Duplicate content means Google is finding multiple versions of the same content and doesn’t know which version to rank. Common causes: HTTP vs HTTPS, www vs non-www, URL parameters creating multiple versions, paginated content without proper handling. The fix is usually canonical tags, 301 redirects, or parameter handling in Search Console.
What to Do With Your Audit Findings
An audit is only useful if it leads to action. Create a prioritised list of issues grouped by impact. Critical issues affecting crawlability or indexation go at the top. Quick wins with minimal development effort come next. More complex improvements are planned in phases. Document everything with recommended fixes and who is responsible.
How Often Should You Audit Your Site?
Technical SEO is not a one-time exercise. Run a full technical audit at least once a year, with lighter monthly checks using Search Console and your crawl tool. After any significant site change — a migration, a domain change, a major redesign — run an audit immediately. These events are the most common triggers for sudden traffic drops.
Ready to Go Deeper?
This guide gives you the framework. For a fuller understanding of each area, work through the rest of the technical SEO series. If you’d rather have a professional do this for you, our SEO consulting service includes a thorough technical audit as the starting point for every engagement.