What is technical SEO?

Short answer

Technical SEO is the layer underneath everything else: making sure Google can crawl your pages, render them, index them, and serve them quickly. It rarely wins rankings on its own. It is regularly what caps a site that should be doing better, and most of the skill is telling a real problem from a red warning icon.

The usual definition is a long list: site speed, sitemaps, robots.txt, canonicals, structured data, HTTPS, mobile-friendliness. All of that is technical SEO. But a list makes it sound like a set of boxes to tick, and that is exactly how technical SEO goes wrong. It is better understood as a sequence of questions.

The four questions technical SEO answers

Google describes search as three stages, crawling, indexing and serving, and notes that not all pages make it through each stage. Technical SEO is the work of making sure your important pages get through all of them, plus one more question about what happens when a person arrives.

Can Google reach it? Crawling. Robots rules, internal links, redirects, status codes, server responses, and the parameter URLs quietly creating endless duplicate space.
Can Google see it? Rendering. On JavaScript-heavy sites, what Googlebot sees after scripts run can differ from what a person sees in a browser. Content and links that only appear late are at a disadvantage.
Does Google keep it? Indexing. Canonicals, noindex, duplicate clusters, soft 404s, and pages Google crawls but decides not to keep.
Does it work for people? Performance. Core Web Vitals and real-world load speed. A genuine but modest ranking input and a large conversion one.

The order matters. Optimising load speed on pages Google cannot reach is a well-intentioned waste of a fortnight.

How it differs from on-page and off-page SEO

On-page SEO is about what a page says and how well it matches a search: content, titles, headings. Off-page SEO is about signals from elsewhere: links, mentions, reviews. Technical SEO is about whether the machinery underneath lets either of those count.

A page with brilliant content that is accidentally set to noindex will never rank. A site with strong links whose internal structure buries the important pages five clicks deep will underperform. Technical problems are rarely the reason a site wins, and very often the reason a site that should win does not.

What technical SEO is not

It is not chasing a score. Audit tools grade sites out of 100 and weight every issue roughly the same. I have seen sites scoring in the sixties rank beautifully and a site scoring 98 sit invisible because of one canonical rule.

It is not fixing everything a tool flags. Most of what tools report has no effect on rankings. A large part of the job is deciding what to ignore.

And for most sites, it is not crawl budget. Google’s own guidance says crawl budget management is aimed at very large sites, roughly a million pages or more changing weekly, or ten thousand or more changing daily. If your site is smaller, Google can crawl it. Whether it chooses to index what it finds is the better question.

What technical problems look like from the outside

Pages submitted in a sitemap that never get indexed. A rebuild in a JavaScript framework followed by a traffic drop. Search Console reporting thousands of URLs you did not know existed. Rankings that collapse on one day with no update running. A page that ranks for a week, disappears, and comes back. Each of those has a technical cause, and each is usually findable.

The status I am asked about most is “Crawled, currently not indexed”. I wrote a full explanation in what crawled, currently not indexed actually means, because it is more often a quality judgement than a technical fault.

Who needs dedicated technical SEO

Large sites, where one template error multiplies across thousands of pages. JavaScript-heavy sites and anything built on a headless setup. Sites that have recently been rebuilt or replatformed. Stores with faceted navigation. And any site where content and links look fine but rankings still will not move.

A small, simple site on a mainstream platform usually needs a technical check once, and then very little after that.

What good technical work produces

Not a spreadsheet of four hundred warnings. A short list of what is actually broken, separated from what a tool flagged but does not matter, with a specification your developer can act on, ranked by impact, and with a way of checking afterwards that each fix worked.

Can you do it yourself?

Some of it. Search Console’s page indexing report, a free crawl of a small site and a look at your robots.txt will catch the most damaging problems: a stray noindex, a blocked folder, a redirect loop, pages nothing links to. Where it gets harder is rendering, large-scale duplication and anything that needs server logs, because those need both the tools and the experience to read what they show. A sensible split is to run the basic checks yourself every few months and bring someone in when something does not add up.

If your content and links look fine and the site still will not move, my technical SEO service diagnoses crawling, rendering and indexation in that order, and writes the fixes for your developers.