SEO Auditing

An SEO audit is a structured review of a website’s technical health, content quality, and backlink profile, carried out to identify what is holding its organic visibility back. The term covers several distinct activities: a technical crawl, an on-page review, a content assessment, a backlink analysis, and increasingly, a check of how the site appears in AI-generated search results. Each component addresses a different category of problem, and most underperforming sites have issues in more than one area.

For the step-by-step process, see the SEO audit guide.

What does an SEO audit cover?

A complete SEO audit has three components, covering visibility across Google’s search ecosystem: technical, content, and off-page. Most site problems fall under at least one of them.

Technical audit

The technical audit checks whether search engines can find, crawl, render, and index the site’s pages correctly. Understanding how search engines work at this level, from discovery through to indexation, is what makes technical fixes interpretable rather than mechanical. A technically flawed site can have excellent content and still fail to rank, because the content is not accessible to search engines in the first place.

Key areas: crawl access and robots.txt configuration, page indexation and noindex directives, redirect chains, duplicate content and canonical tag accuracy, page speed and Core Web Vitals, mobile usability, structured data markup, HTTPS configuration, and sitemap accuracy.

Content audit

The content audit assesses the quality and relevance of what is on the pages Google has indexed. Content problems are harder to fix than technical ones because they require editorial work, but they are often the primary reason a technically sound site is not ranking.

Key areas: thin pages with insufficient information to satisfy a query, pages targeting overlapping keywords that compete with each other (keyword cannibalisation), duplicate content across multiple URLs, and pages that have lost rankings over time without obvious technical cause. Content pruning, the removal or consolidation of thin or underperforming pages, is one of the most common corrective actions. Where a page has partial value, a content refresh, updating facts, structure, and coverage rather than starting over, is often more effective than removal. Tracking ranking movement after audit changes helps calibrate the SEO timeline for each fix. Calculating SEO ROI from that work requires a value framework that converts traffic improvements into monetary terms.

Off-page audit

The off-page audit reviews the site’s backlink profile: how many links it has, where they come from, how relevant those sources are, and whether any are potentially harmful. Off-page factors cannot be fixed directly, but they can be managed through outreach, disavow files, and link acquisition.

Key areas: referring domain count and quality, anchor text distribution, toxic or unnatural link patterns, and comparison against competitor backlink profiles.

On-page audit

The on-page audit reviews how well individual pages are optimised for the queries they target. Unlike the technical audit, which looks at site-wide infrastructure, on-page work is page-level: title tags, meta descriptions, heading structure, keyword alignment, and internal linking. A page can be fully crawlable and still fail to rank if it is targeting the wrong query or signalling the wrong topic.

AI visibility

With AI Overviews now appearing across a large share of Google searches, audits increasingly include a check of how the site’s content is retrieved and cited by Google’s AI features. The key areas: whether structured data is complete and error-free, whether page sections are self-contained enough to be extracted as standalone passages, and whether the site is recognisable as a named entity in Google’s Knowledge Graph.

When should you run an SEO audit?

Quarterly review: A lightweight check of crawl errors, indexation status, Core Web Vitals, and GSC performance data is enough to catch problems early. Full audits do not need to be quarterly.

After major changes: Site migrations, CMS changes, significant redesigns, and large-scale content restructuring can all introduce technical problems. An audit immediately after go-live confirms nothing was broken in the process.

Before a migration: An audit before a migration establishes a baseline for redirect mapping, identifies existing issues that the migration should not carry forward, and captures current performance data for comparison post-launch.

When rankings drop unexpectedly: A sharp decline in organic traffic is usually traceable to a technical change, algorithm update, or content quality issue. An audit provides the diagnostic framework for finding the cause.

What tools do you need for an SEO audit?

Google Search Console is the starting point for any audit. The Page Indexing report shows which pages are indexed and why others are not. The Performance report shows queries, clicks, and impressions. Core Web Vitals data comes from real users. It is free and, for indexation and performance data, more reliable than any third-party alternative.

Screaming Frog SEO Spider crawls a site the way Googlebot does, returning status codes, redirect chains, duplicate content, missing meta data, and much more. The free version handles up to 500 URLs; the paid version is uncapped.

Sitebulb is an alternative crawler with a more visual interface, particularly strong for architectural analysis and rendering issues.

Ahrefs Webmaster Tools (free) provides backlink data and the ability to see which keywords a site ranks for, making it useful for both the content and off-page components of an audit.

Google PageSpeed Insights and Lighthouse measure Core Web Vitals and page speed, with field data (real user measurements) and lab data (simulated test conditions).

What to do with findings

The output of an audit should be a prioritised action list, not an exhaustive report of everything wrong. Most sites have dozens of improvable things. The ones worth fixing first are those with the highest impact on crawlability, indexation, and on-page quality. Tracking how performance responds to those fixes is where SEO analytics comes in, tying audit outcomes to impression and traffic trends over time.

Fix technical blockers first. A crawl issue that prevents indexation of important pages takes priority over any content improvement. Content improvements only matter if the pages can be found.

Group findings by effort and impact. Quick wins that take little development time and produce clear improvements should come before longer projects. Deprioritise cosmetic issues that do not affect search visibility.

For the full process, see the SEO audit guide.