Technical SEO Basics

Technical SEO is the part that decides whether anything else you do counts. A page Google cannot reach, cannot read, or refuses to index does not rank, however good the writing is and however many sites link to it. It is plumbing, and like plumbing you only think about it when it fails.

What counts as technical

Everything about how a search engine reaches and processes your site, rather than what the site says. Whether a page can be fetched. Whether Google is allowed to fetch it. Which address it files the page under when several point at the same thing. Whether the page arrives fast enough to be usable. Whether the facts on it are readable by a machine.

The reassuring part: on a small site built with a modern platform, most of this is handled for you and correct by default. The dangerous part: when it is wrong, nothing looks wrong. Every one of the failures in this section leaves a website that loads perfectly for visitors while quietly disappearing from search.

That is why technical SEO is worth an hour of checking even when nothing seems to be the matter. You cannot feel it from the outside.

The five topics in this section

Start with the first one even if you read nothing else. Everything in SEO assumes it.

• How Google Search works: crawling, indexing and serving are three separate steps, and a page can pass one and fail the next.
• Sitemaps and robots.txt: two small files that do opposite jobs. One of them can remove your entire site from Google with a single line.
• Canonicals and duplicate content: the same page usually has several addresses, and Google picks one. There is no duplicate content penalty, but there is a way to lose a whole site to one tag.
• Structured data: the code behind star ratings and breadcrumbs in results. What it makes you eligible for, and what it never promises.
• Core Web Vitals: "make your site faster" turned into three numbers you can actually measure, with Google's published thresholds.

What to check first

• Search site:yourdomain.com in Google. If your pages are not listed, nothing else in SEO matters yet; you have a visibility problem, not a ranking one.
• Set up Google Search Console and verify the site. It is free, it is Google telling you directly what it sees, and no third-party tool substitutes for it.
• Open yourdomain.com/robots.txt and read it. Confirm it does not say Disallow: /.
• View the source of your homepage and find the rel="canonical" tag. Confirm it points at your real domain, not a staging one.
• Load the site on a phone, on mobile data, and see how it actually feels.

Five checks, no tools beyond a browser and a free account. They catch the majority of the failures that matter.

Sources: Crawling and indexing documentation and Understanding page experience.