What does an SEO audit include?

An SEO audit is the systematic inspection of every signal that influences how search engines (and AI answer engines) find, understand, rank, and cite your website. A good audit produces three things: a complete list of issues, a prioritised order in which to fix them, and the diagnostic context needed to actually fix each one. Anything less is a glorified Lighthouse export.

Technical SEO is the foundation: can search engines crawl your URLs, parse the response, and decide which version to index? This category covers robots.txt, XML sitemaps, canonical tags, redirect chains, status codes, hreflang for multi-region sites, and JavaScript rendering. A single misconfigured canonical can suppress an entire section of a site from Google for months — this is why technical SEO appears first in the audit hierarchy.

Core Web Vitals is now a ranking signal in Google's algorithm: LCP measures perceived load speed, INP measures interaction responsiveness, and CLS measures layout stability. The three thresholds (2.5s, 200ms, 0.1) are not arbitrary — they represent the 75th-percentile user experience target Google uses to define a 'good' page. A page that fails any one of the three is at material risk of ranking suppression, particularly in the mobile index.

Structured data (Schema.org JSON-LD) is what unlocks rich-result formats in Google search — review stars, FAQ accordions, breadcrumb trails, business hours. The right schema for your business depends on the entity type: LegalService for law firms, AccountingService for accountants, MedicalClinic for healthcare, Product for e-commerce. A correctly marked-up page can lift CTR by 20–60% versus the same page with no schema.

Content quality covers the editorial layer: are your pages substantive, original, and authored by named experts (E-E-A-T)? Are they structured for passage-level extraction so AI answer engines can cite specific paragraphs? Is your thin-content ratio under control? This category is where most programmatic content programmes break — generating 60 near-duplicate pages and watching Google prune most of them.

AI search visibility is the newest audit category and the fastest-growing. AI Overviews now appear on a majority of UK informational searches; ChatGPT and Perplexity influence procurement research before a buyer ever clicks a Google result. A modern audit measures llms.txt parity, citability score, and brand-mention frequency in AI answers — because being absent from the answer is the new being absent from page one.

Conversion UX is included because diagnostic audits without a conversion lens optimise the wrong thing. Ranking #1 on Google is worthless if the landing page has a 6-second LCP, a confusing form, and no proof signals. The audit measures form friction, tap-target sizing, contrast ratios, and trust-element placement — the controllable factors that translate ranking into revenue.