Technical SEO is the part of SEO concerned with making sure search engines and AI models can reach your site, understand its content, and display it. It is not about the words you write, but about the infrastructure that holds them up: that your pages can be crawled, indexed, loaded fast, and read without ambiguity. Without that foundation, the best content in the world stays invisible.

Crawling: letting bots reach your content

Before Google can rank a page, it has to find it and read it. That process is called crawling, and it is done by programs that move across the web following links.

If a bot cannot reach a page, that page does not exist for the search engine. Blocks are usually accidental. A misconfigured robots.txt file that closes off entire sections, an architecture where important pages sit too many clicks from the home page, broken internal links that cut the path short.

Three things help crawling flow:

  • A robots.txt that blocks only what genuinely should not be crawled and leaves everything else open.
  • An internal link structure where every relevant page is reachable in a few hops from the home page.
  • An updated XML sitemap, submitted in Google Search Console, that serves the search engine as a map of your site.

Crawling is the first bottleneck. If it fails here, nothing that comes after matters.

Indexing: getting your pages into Google’s index

A page being crawled does not guarantee it gets indexed. Indexing is the next step: Google decides whether to store that page in its index, which is where it pulls results from when someone searches.

A page can stay out of the index for several reasons. A noindex tag someone left in place by mistake. Content Google considers duplicate or thin. A canonical signal pointing to another URL, telling Google that one is the good version.

The tool for diagnosing this is Google Search Console. Its page indexing report tells you which pages are indexed, which are not, and why. Checking it from time to time prevents the surprise of finding that key pages had been out of the index for months without anyone noticing.

A practical rule: every page you want to rank should be indexable, have a single clear canonical version, and not be blocked by accident. It sounds obvious, and it is one of the most common mistakes there is.

Core Web Vitals: making your site load fast and well

Google uses page experience as a signal, and it measures it with three metrics known as Core Web Vitals. Each one captures a different part of how loading your site feels.

LCP, Largest Contentful Paint, measures how long the main element of the page takes to appear, usually the largest image or block of text. It reflects perceived load speed. A good LCP is under 2.5 seconds.

INP, Interaction to Next Paint, measures how long the page takes to respond when the user interacts, for example when tapping a button. It captures how responsive the site feels. INP replaced the older FID metric and is considered good under 200 milliseconds.

CLS, Cumulative Layout Shift, measures how much the content moves while it loads. If you have ever tried to tap a button and the page jumped, leaving you somewhere else, that is a high CLS. Good is under 0.1.

These metrics are not a performance luxury. On mobile, where much of the traffic sits, a slow site loses people before they see anything. Improving Core Web Vitals almost always means optimizing images, reducing code weight, and serving the main content as early as possible.

Structured data: making content readable without ambiguity

Structured data is code you add to your pages to describe what each thing is to the search engine. You tell it explicitly that this is a product, this is its price, this is a review, this is a frequently asked question. The standard format is schema.org, usually implemented with JSON-LD.

The value is twofold. On one hand, it enables rich results: those star ratings, prices, or expandable questions you see in some results, which attract more clicks. On the other, it removes ambiguity from your content. Instead of asking Google to guess what a number on your page means, you tell it.

That clarity became more important with AI. When a model decides what to cite while answering, content that is well marked up and easy to interpret has an advantage over content that forces it to infer. Structured data does not guarantee you will be cited, but it removes friction.

AI bot access: letting models read you

There is a new layer in technical SEO that did not exist until recently: access for AI crawlers. The models that answer questions, like ChatGPT, Perplexity, or Google’s AI features, use their own bots to read the web.

Some worth knowing are GPTBot, from OpenAI, PerplexityBot, and Google-Extended, the control Google uses to manage how your content is used in its AI products. You allow or block each one from your robots.txt.

There is a real decision here, not a single answer. If you want your brand to show up cited in these systems’ responses, those bots have to be able to read you. Blocking them takes you out of that conversation. Allowing them means opening your content to that use. What matters is that it be a conscious decision and not a default block that leaves you out of a fast-growing source of visibility.

Where to start

Technical SEO feels overwhelming because it touches many pieces at once. The sensible order is from the bottom up. First confirm that your pages are crawled and indexed, because without that nothing else counts. Then measure your Core Web Vitals and fix whatever is in the red. After that, add structured data where it helps and review what your robots.txt does with AI bots.

Most technical problems are invisible from the outside and only surface when someone goes looking. An orderly SEO audit brings them to light before they cost you traffic. If you prefer to understand the full landscape first, this is the foundation of technical SEO that everything else is built on.