The short version: there are nine recognised types of technical SEO, but most small and medium business sites only need to get four of them right to see real movement in rankings. The other five matter more as your site grows past a few thousand pages, and agencies know that but rarely say it out loud because complexity sells bigger invoices.
I’ve been doing this since before “technical SEO” was even a phrase people used, back when we just called it “making sure Google can read the bloody site.” So when a client asks me how many types they need to learn, I don’t hand them a textbook list. I tell them the truth, which is that knowing all nine is good for your CV, but knowing which four apply to your site right now is what gets you found on Google.
The nine types of technical SEO, in the order they usually matter
I’ve grouped these the way I’d explain them to a client over coffee, not the way a certification course would. Some of these overlap. That’s normal. Technical SEO isn’t neat.
1. Crawlability
This is whether Googlebot can even get into your site and move around it. It lives in your robots.txt file, your crawl directives, and how your internal links are structured. If you block the wrong folder in robots.txt (I’ve seen agencies do this to entire staging sites that went live still blocked), Google never sees the pages at all. No indexing conversation is worth having until crawlability is sorted.
2. Indexability
Different from crawlability. Google can crawl a page and still choose not to index it, or you can tell it not to via a noindex tag or a canonical pointing somewhere else. This is the one that quietly wrecks the most sites, and I’ll come back to it with a real story in a minute.
3. Site architecture and internal linking
How your pages connect to each other. A flat structure where every important page is three clicks or fewer from the homepage tends to get crawled and ranked faster than a deep, buried structure. This is also where internal links do double duty, the same way backlink strategy works externally, your internal links pass authority around your own site.
4. XML sitemaps
A map you hand Google directly, listing the URLs you want indexed. Small sites can survive without a perfect one. Sites over a few thousand pages cannot, because you need to tell Google what matters when it can’t work that out alone.
5. Site speed and Core Web Vitals
Largest Contentful Paint, Interaction to Next Paint, Cumulative Layout Shift. Google has used these as ranking signals since 2021, and PageSpeed Insights will score you out of 100 for free. In my experience a site scoring under 50 on mobile struggles to rank against competitors scoring 80 plus, all else being equal.
6. Mobile and responsive technical SEO
Google has indexed mobile-first since 2019, meaning the mobile version of your site is the one that gets evaluated, not the desktop version. I still find sites in 2026 where the mobile menu hides key navigation links that exist fine on desktop, which means Google’s crawler can’t see them.
7. Structured data and schema markup
The code that tells Google “this is a recipe” or “this is a product with a price of £45 and 4.6 stars.” It doesn’t directly boost rankings but it earns you rich results, star ratings, FAQ dropdowns, which lift click-through rate even at the same position.
8. International SEO (hreflang)
Only relevant if you serve multiple countries or languages. Hreflang tags tell Google which version of a page to show a French visitor versus a British one. Get this wrong and you get the wrong country’s pricing showing up in the wrong search results, which I’ve watched happen to a client selling into both the UK and US markets simultaneously.
9. JavaScript SEO
Sites built on React, Vue, or heavy JavaScript frameworks need special handling because Google has to render the page before it can read it, and rendering isn’t instant or guaranteed. This is the most technical of the nine and honestly the one I bring in a developer for rather than trying to fix myself.
The real story: how one missed canonical tag cost a client 40% of their traffic
A few years back I worked with a WooCommerce store that redesigned its whole site with a new theme. The developer, a good one otherwise, migrated everything except the canonical tags on category pages. Every filtered version of a category (sorted by price, sorted by newest, filtered by size) ended up pointing its canonical tag at itself instead of the main category page.
Within six weeks Google Search Console showed a 40% drop in organic sessions. Coverage report was full of “duplicate, Google chose different canonical” warnings, hundreds of them. We found it through Search Console’s index coverage tab, cross-checked it in Screaming Frog, and fixed it in an afternoon once we knew what we were looking for. Traffic recovered over the following two months, but that’s two months of lost sales because one tag type, out of nine, went unchecked after a migration.
That’s the pattern I see over and over. It’s rarely the exotic stuff, the hreflang or the JavaScript rendering, that tanks a site. It’s the boring, unglamorous basics, indexability and crawlability, that get missed because nobody thought to check them after a change.
Here’s the uncomfortable bit nobody in this industry likes to say plainly
Most technical SEO audits sold to small businesses are padded. I’ve seen agencies charge £3,000 to £5,000 for an audit that runs Screaming Frog, exports 200 “issues,” and hands over a PDF where 180 of those issues are things like “missing alt text on decorative images” or “meta description slightly over 160 characters,” neither of which moves a needle for a 150-page local business site.
Crawl budget optimisation, the kind of thing that gets whole chapters in technical SEO courses, only matters once you’re past roughly 10,000 pages and Google is struggling to crawl all of you in a reasonable time. If you run a site with 80 pages, crawl budget is not your problem, and paying someone to “optimise” it is paying for reassurance, not results.
The four types that move the needle for most businesses under a few thousand pages are indexability, site speed, mobile usability, and internal linking. The other five are real, worth knowing about, and worth fixing eventually, but they are not where your limited time or budget should go first.
A six-step check you can run yourself this afternoon
You don’t need to hire anyone to get a first-pass read on where you stand. Here’s the order I use with new clients:
- Open Google Search Console and check the Index Coverage report for anything marked “excluded” that shouldn’t be, that’s your indexability check done in five minutes.
- Run your homepage and your top three landing pages through PageSpeed Insights and note the mobile score. Under 50 means speed is costing you rankings right now.
- Check robots.txt manually by typing yourdomain.com/robots.txt into a browser and reading it line by line, looking for anything blocking folders you want indexed.
- Search “site:yourdomain.com” in Google and scroll through what’s indexed versus what you expected to see there.
- Click through your site on your phone specifically, not a desktop browser resized smaller, an actual phone, and check every important page loads its navigation and content.
- Count how many internal links point to your three most important pages. If it’s fewer than five each, that’s your architecture problem right there.
That six-step version won’t catch everything, but it catches most of what damages small business rankings, and it takes an afternoon rather than a five-figure retainer.
When to bring in a specialist versus when to fix it yourself
Crawlability, indexability, sitemaps, and basic speed fixes are things a business owner or marketing person can learn to check within a day or two, using free tools. JavaScript SEO and complex international hreflang setups are where I bring in a developer, because getting them wrong quietly and getting them wrong loudly look identical until you check Search Console weeks later.
If you’re building out a content and marketing team around your site, it’s worth knowing that the person writing your blog posts, the kind of role covered in this piece on what freelance writers should know before taking remote writing jobs, is not the same skill set as the person who should be touching your robots.txt file. I’ve seen well-meaning writers “clean up” a sitemap and accidentally deindex half a blog. Keep the roles separate.
Similarly, if the technical fix requires custom development, that’s a job for an actual engineer, not a general VA. The kind of talent described in this guide to remote software engineer roles for juniors gives you a decent sense of what a junior developer can competently handle versus what needs someone more senior. JavaScript rendering issues usually need the senior end of that spectrum.
Where technical SEO fits alongside everything else you’re doing
None of this happens in a vacuum. Technical SEO gets your pages seen and indexed correctly, but it doesn’t build the audience that finds those pages in the first place. That’s a distribution job, the sort of daily consistency question I’ve written about before in relation to whether you should post on LinkedIn every single day. Technical SEO and social distribution solve different problems, and businesses that only do one tend to plateau.
I’d rather a client know four types of technical SEO cold, indexability, speed, mobile, and internal linking, and fix them, than know all nine at a surface level and fix none of them well. Depth beats breadth here every single time.
If you want the wider picture, see What is technical SEO and which parts matter for a small business webs.
Frequently asked questions
How many types of technical SEO are there in total?
Most SEO professionals recognise nine distinct types: crawlability, indexability, site architecture and internal linking, XML sitemaps, site speed and Core Web Vitals, mobile technical SEO, structured data, international SEO (hreflang), and JavaScript SEO.
Which type of technical SEO matters most for a small business website?
Indexability matters most, because a page that isn’t indexed can’t rank at all no matter how good the content is. Site speed and mobile usability come next, since Google evaluates the mobile version of your site first.
Do I need to fix all nine types of technical SEO before I can rank?
No. Sites under a few thousand pages rarely need to worry about crawl budget or hreflang, and JavaScript SEO only matters if your site is built on a heavy framework like React. Fixing indexability, speed, mobile usability, and internal linking covers most of the ranking impact for a typical small business site.
How often should I check my site’s technical SEO?
Check Google Search Console’s Index Coverage report monthly, and do a fuller manual check anytime you migrate platforms, change themes, or launch a redesign, since that’s when canonical tags, robots.txt rules, and sitemaps most often break silently.
