Technical SEO audit checklist: the 25 checks that matter

A technical SEO audit is a health check for the parts of your website that visitors never see and Google never forgives. It asks a simple question: can Google find your pages, read them, and trust them enough to show them? If the answer is no for a page that should bring in customers, no amount of keyword tweaking will save it.

Small business sites fail audits in predictable ways. A redesign leaves old pages returning errors. A plugin blocks a whole section by accident. Images grow so large that a service page takes six seconds to load on a phone. None of these problems announce themselves. The site looks fine to its owner, while Google quietly stops showing it. This checklist covers the 25 checks that matter, grouped so you can work through them in order and stop guessing.

What a technical SEO audit actually covers

Technical SEO is everything about your site except the words on the page. It covers crawling, which is Google finding your pages; indexation, which is Google keeping them in its index; rendering, which is Google seeing the page the way a visitor sees it; and the signals that tell Google the site is fast, secure and trustworthy. Content decides whether a page deserves to rank. Technical SEO decides whether it gets the chance.

That distinction is why audits start with the plumbing. A beautiful service page that returns a 404 error is not a ranking opportunity, it is a dead end. A page that Google has never crawled because robots.txt blocks it is invisible, however well it is written. And a page that loads in eight seconds on a phone will lose most of its visitors before they read a word. The audit below checks the plumbing first, then the polish.

“A site that Google cannot crawl is a brochure in a locked drawer. Open the drawer first, then worry about the wording.” — Shamim, founder of Serpastra

Before you start: the tools and access you need

You need three free tools and one login. Google Search Console shows what Google has actually crawled and indexed, and it is the only source that speaks for Google itself. PageSpeed Insights measures real loading experience on mobile and desktop. A crawler such as Screaming Frog, which offers a free version for small sites, lists every URL, status code and redirect on your site in minutes.

You also need access to the site itself: the content management system, the hosting account or the developer who manages it. An audit that finds problems nobody can fix is a report, not a result. Before you start, agree on who will make the changes. If that person is a developer, ask them to sit in on the findings review so nothing gets lost between the report and the fix.

Crawl and indexation checks (1–6)

Site structure and internal linking (7–10)

Page speed and Core Web Vitals (11–14)

Mobile and rendering checks (15–17)

Structured data and rich results (18–20)

Security, HTTPS and international checks (21–23)

Analytics and tracking checks (24–25)

Turning findings into a fix list

An audit that lists fifty issues in no order is almost useless. Rank every finding by two things: how much traffic or revenue is at risk, and how much effort the fix takes. A broken booking page is urgent even if the fix is hard. A missing alt tag on an old blog image is not urgent even if the fix is easy.

Put the fixes into three groups. The first group is anything that stops Google reaching or indexing money pages — blocking rules, errors, wrong redirects. The second group is anything that costs conversions — slow pages, mobile problems, broken forms. The third group is everything else, worked through steadily over the following weeks. A developer can usually clear the first group in days. The second group takes a few weeks. The third group is ongoing maintenance, and that is normal: websites are never finished, they are maintained.

One more discipline matters: re-check after every fix. Re-crawl the site, re-test the page, and confirm in Search Console that the error is gone. A fix that nobody verifies is a guess, and guesses have a habit of coming back as the same error three months later. Keep the list visible to everyone involved and update it as fixes land, so the audit stays a working document rather than a file nobody opens again.

How often to audit, and when to get help

Run the full 25-check audit once a year, and a short version every quarter: crawl errors, indexation, speed on money pages, and Search Console warnings. Run it immediately after any redesign, platform move, domain change or major content migration — those are the moments when technical problems are born.

If the audit finds problems you cannot fix in-house, that is the right time to bring in help. A one-time audit from a specialist should give you the findings, the fix list in priority order, and the reasoning behind each recommendation, so your developer can act on it without a second round of questions. Serpastra's one-time SEO audit costs $349 and covers all 25 checks in this guide. If you would rather have the fixes managed month to month, our guide to how much SEO costs explains what monthly plans include and what they should cost. And if you are still deciding who to hire, our questions to ask before hiring an SEO will help you sort good providers from smooth talkers.

Sources we checked

1. Google Search Central — SEO Starter Guide: the official basics on crawling, indexing, titles and links.
2. Google Search Central — Technical SEO techniques and strategies: crawl control, redirects, structured data and site moves.
3. Google Search Central — SEO guide for web developers: rendering, JavaScript and how Google sees your site.
4. Google Search Console Help — Page Indexing and Core Web Vitals reports, as used in Search Console itself.
5. Schema.org — LocalBusiness and review markup types, as referenced in Google's structured data documentation.