Technical SEO is not a way to get higher rankings - it is the condition without which the rest of the work has nothing to stand on. That distinction sounds like splitting hairs and it is the most important thing in the topic: a site with no technical foundation will not rank, but the foundation on its own will not give it position either. It is the floor, not the lift.
I am writing this because “technical SEO” turns up in proposals as a term nobody defines - and the client pays for something whose scope they do not know. Below: the definition, the boundaries, a list of what genuinely falls in scope, and an honest answer on how much of it an ordinary business website needs.
The definition in one sentence
Technical SEO is everything that determines whether a search engine can fetch, understand and display your site - before it even starts judging what you wrote on it.
Note the order. The robot first has to get in, then fetch, then understand the structure, and only at the end does it assess the content. Every one of those steps can fail for reasons that have nothing to do with the quality of the text.
Three layers, and where the technical one ends
Search visibility breaks into three layers. The boundaries between them blur, but the split is practical, because each layer is done by different people and measured differently:
| Layer | What it decides | Who usually does it |
|---|---|---|
| Technical | whether the site can be fetched, indexed and displayed quickly | developer |
| On-page and content | whether the page answers what somebody is looking for | copywriter, SEO specialist |
| Authority | whether others treat the site as a credible source | SEO specialist, marketing, PR |
The technical layer is the only one of the three where a state of “done” exists. Content is written without end, authority is built over years - but the technical side has a target state you reach and then simply keep from slipping.
That matters when buying the service: technical work has a sensible shape as a project with an end date. A retainer “for technical SEO” with no defined task list is suspicious. How to read proposals like that at all, I described in the piece on how to buy SEO without getting scammed.
The seven areas that make up technical SEO
This is the scope worth asking about when somebody offers “technical optimisation”.
1. Access for robots
Whether the search engine is allowed in at all. That is decided by the robots.txt file, noindex tags in the page code, the visibility setting in WordPress and - increasingly - the hosting firewall, which can block crawlers as “suspicious traffic”.
The most common mistake in the world: after a rebuild, a site keeps the indexing block that was switched on during the work. It looks and works perfectly, it is just not in Google. Check that first, before touching anything else.
2. Indexing and crawl budget
Getting in is not the same as being indexed. A robot can fetch a page and decide it is not worth keeping in the index - because it duplicates another, because it is empty, because a single forgotten link points at it.
On top of that comes crawl budget: a robot gives each site a limited amount of attention. On a ten-page site that is completely irrelevant. On a store with thousands of filter URLs it is critical, because the robot can burn all its attention on “colour + size + sort order” variants and never reach the products.
3. URL architecture and redirects
One version of the address (with or without www, over https), readable page URLs, correct 301 redirects after every structural change, and no redirect chains.
This is the area where years of work are easiest to lose in a single day. A site rebuild with no map of redirects from old URLs to new ones wipes the history of every page that had rankings. How to run that change without losses I wrote up in migrating without losing rankings - the mechanism is the same whether you are changing platform or only rebuilding the site.
4. Speed and Core Web Vitals
Time to the server’s first response, time until the main content appears, layout stability while loading, response to a tap. Google measures this with a set of metrics and treats it as a ranking factor - but the real reason you do it is different: a slow site loses people before they see anything.
The concrete work on that side - hosting, caching, images, scripts - I set out in the guide to speeding up a WordPress site, and the metrics and their thresholds in Core Web Vitals for a store.
5. The mobile version
Google judges a site on its mobile version. Not “also checks” - judges that one. If content present on desktop is missing on the phone, then as far as the search engine is concerned that content does not exist.
Plus the things that break usage: buttons too small to hit with a thumb, forms triggering the wrong keyboard, content requiring horizontal scrolling, pop-ups covering the screen.
6. Security and server hygiene
A valid SSL certificate and consistent https, no mixed content, stable server response codes, no malicious code. This is the layer nobody thinks about until it breaks - and it breaks loudly: an expired certificate throws a browser warning and stops traffic within hours. What to do then I described in SSL certificate expired.
7. Describing the site for machines
Structured data, a correct heading hierarchy, sensible titles and descriptions, a sitemap, language versions. This is the layer that does not tell the robot “what is written here” but “what this is”: a company, a product, an article, an event.
Its importance is growing, because AI engines lean on it harder than classic search does - I write about that at length in SEO and AI.
What technical SEO will not do
An honest list, because this is where most of the disappointment is born:
- It will not replace content. A perfectly optimised page with no answers to customer questions will not rank for anything valuable. The robot gets in, understands, and decides there is nothing to show.
- It will not build authority. No markup will make Google treat you as a credible source in your field.
- It will not create an effect where there is no demand. If nobody types what you sell into a search engine, technical work will not generate the queries.
- It is not a one-off forever. A theme update, a new plugin, a menu rebuild - any of those can undo part of the work. That is why a project leaves behind a checking routine, not just a sign-off.
Who does it: developer or SEO specialist
The split that works in practice:
The SEO specialist finds the problem and states the required outcome: “these 40 pages are not indexed”, “the site takes 6 seconds on mobile”, “the rebuild lost 120 URLs”.
The developer fixes it, because the fix means a change in the code, the server configuration or the template.
The market problem is that plenty of “technical SEO” offers stop at the first part - the client gets a report listing errors and is left alone with it. A report is not a repair. When ordering, ask outright whether implementation is in the price or only the diagnosis. What a proper audit should contain, and where its scope ends, I set out in SEO audit cost and scope.
How much of it you actually need
The scale of the need differs by an order of magnitude, and that is the answer most articles about technical SEO leave out.
A business site of 10-20 pages. You need seven things: one version of the address, valid SSL, a correct robots.txt, a sitemap, sensible titles, a mobile version and reasonable speed. That is a project of a few to a dozen or so hours, done once. Crawl budget, filter canonicalisation and category architecture do not concern you - you have twenty URLs and a robot walks them in a minute.
A store with thousands of products. This is where real technical SEO begins: handling filters and sorting, canonical URLs, pagination, product variants, discontinued products and what happens to them, performance on a large catalogue, a sitemap split into parts. Here technical work can be the main source of growth, and here ongoing care of that layer makes sense.
A content site, blog or portal. Somewhere in between, with the emphasis on internal linking structure, tags generating hundreds of thin pages, and speed with heavy images.
The practical conclusion for most companies: if you have an ordinary business website, technical SEO is a one-off clean-up, not a monthly service. The money spent afterwards on content answering customer questions will do more.
How to check in three minutes whether you have a technical problem
Three tests, one minute each, that filter out most cases:
- Type
site:yourdomain.cominto Google. Does the number of results roughly match the number of your pages? Good. Zero results, or five when you have fifty pages? You have an indexing problem, and it is the priority before anything else. - Open the site on a phone, on mobile data. Does the main content appear in two to three seconds? Good. Longer than four - you have a speed problem.
- Check the padlock in the address bar and visit a few pages. A warning about an insecure connection, or a redirect loop, means a problem with the certificate or the URL configuration.
If all three come out fine, your site most likely has no technical problem blocking visibility - and the budget is better spent elsewhere. The full list of checks, in case one of the tests came out badly, is in the SEO audit checklist.
FAQ
What is the difference between technical SEO and on-page SEO? Technical answers “can the search engine”, on-page answers “is it worth showing”. Technical means indexing, speed, URLs, code. On-page means titles, headings, content, keywords, internal linking. The boundary blurs - a page title gets counted in both - but the rule is: if it improves machine comprehension, it is technical; if it improves relevance for a human, it is on-page.
Does an SEO plugin cover technical SEO?
Partly, and that is worth knowing before you buy. A plugin generates a sitemap, lets you set titles and descriptions, adds basic structured data and a noindex switch. It will not speed the site up, will not fix hosting, will not set up redirects after a rebuild, and will not solve a store’s filter problem. That is a small share of the scope, handled conveniently.
What does technical SEO cost? It depends on scale, and the spread is huge - from a few hours on a small business site to a project of weeks on a large store. An honest quote starts with looking at the specific site, not with a price list. What to settle before signing: whether the price covers implementation or only a report listing errors.
Does technical SEO have to be done every month? On an ordinary business website, no - it is a one-off project plus periodic checks, say every six months and after every larger change. On a store with a big catalogue, yes, because the catalogue is alive: products come and go, filters generate new URLs, integrations add their own. There it is part of ongoing care, not a separate service.
I did technical SEO and nothing changed. Why? Most often because the technical side was not the bottleneck. If the site was indexed, fast and correct, the clean-up unblocked nothing - because nothing was blocked. The cause of the missing visibility then sits in the content, or in the fact that nobody searches for what you offer. The order is thankless but it is the only sensible one: first check whether the technical side is blocking, and if it is not, stop investing there.
Want your company to show up in Google and in ChatGPT answers? I work on technical SEO and AI visibility from the code side, not the reporting side. Tell me which questions matter to you and I will quote it.