Free SEO audit tool

A technical SEO audit is a check of whether a search engine can crawl, render, understand and index your pages. It looks at the machinery rather than the words: robots.txt rules, status codes, redirects, canonical tags, sitemaps, headings, structured data and internal links. The output is a list of faults that stop pages ranking, ordered by how much damage each one does.

A complete audit covers five areas. Crawlability and indexing, which decide whether a page can appear at all. On-page elements: titles, meta descriptions, headings and content. Site architecture: internal links, URL structure, redirects and orphan pages. Machine-readable markup: canonicals, hreflang, structured data and Open Graph tags. And performance, meaning how fast the server answers and how the page behaves once loaded.

Once a month is enough for a site that is not changing much, and once a quarter is the minimum for anything. Always run an audit after a redesign, a domain migration, a CMS upgrade or a platform change, because that is when canonicals, redirects and robots.txt rules break. Those faults are invisible on screen and expensive in the results pages, which is why they need checking rather than noticing.

Technical SEO is about access: can a crawler reach the page, read it and index it. On-page SEO is about relevance: does the title, the content and the markup match what someone searched for. Technical work has to come first, because the best page on the internet earns nothing if a Disallow rule is hiding it.

The recurring ones are missing or duplicated title tags, pages blocked by robots.txt or a stray noindex tag, canonical tags pointing at the wrong URL, redirect chains left behind by a migration, broken internal links, and URLs that exist but appear in no sitemap and no menu. Most of these come from a change made for another reason. None of them announce themselves.

A canonical tag tells a search engine which URL is the real version of a page when several URLs show the same content. You need one whenever the same content is reachable at more than one address: tracking parameters, print versions, filtered category pages, or the same article under two paths. Without it the search engine picks for you, and it often picks the wrong one.

Check four things in order. Does robots.txt allow the URL, does the server return a 200 rather than a redirect or an error, does the page carry a noindex directive in its HTML or HTTP headers, and does the canonical tag point at itself rather than at somewhere else. If all four are clean the page is indexable, and anything still missing from the index is a quality or discovery problem rather than a technical one.

It is two separate decisions, and it helps to treat them that way. Search crawlers such as OAI-SearchBot, PerplexityBot and Claude-SearchBot decide whether your pages can be cited in AI answers, so blocking them removes you from that surface. Training crawlers only feed model training and give nothing back directly. Many sites allow the first group and block the second, which robots.txt lets you do with one rule per user agent.