Which SEO basics do machines still depend on?

Each redirect hop is another request an AI client or crawler has to make before it reaches your content, and some give up. A single clean redirect is normal; a chain of them is latency you are adding to every visit. A page that does not answer at all is reported separately, as a refusal rather than a score.

What good looks like The URL answers directly, or through one clean redirect.

A Cache-Control, ETag, or Last-Modified header lets browsers and CDNs skip re-downloading an unchanged page — faster repeat visits, less server load, and a small hand to crawlers hitting you often.

What good looks like The page sends a Cache-Control, ETag, Last-Modified, or Expires header.

Serving the same content on both www and non-www (or http and https) splits ranking authority.

What good looks like All variants 301 to one preferred host.

A stray Disallow: / can hide your whole site from search; a missing robots.txt leaves crawling ambiguous.

What good looks like A valid robots.txt that allows your public pages and links to the sitemap.

A meta robots or X-Robots-Tag noindex removes the page from search entirely — often left on by mistake after launch.

What good looks like No noindex on pages you want found.

The canonical consolidates ranking signals onto the URL you want and resolves duplicate-content ambiguity. It counts whether you declare it as a link element or an HTTP Link header — Google treats both the same.

What good looks like A self-referencing canonical pointing to the preferred, on-domain URL — as a <link rel="canonical"> element or a Link: rel="canonical" response header.

The title is the strongest on-page relevance signal and the first thing a search engine or an answer engine reads to know what a page is. A page with no title is unnamed to a machine.

What good looks like Every page has a unique, keyword-led title element.

A meta description is a short, author-written summary in a fixed place that search engines, answer engines and link previews all read. A page without one leaves a machine to summarise it by guesswork.

What good looks like A unique description that sums up the page, declared with the name attribute.

The H1 states the page topic to crawlers and AI. Without one, a machine has to guess what the page is about.

What good looks like An H1 that states the page's topic.

A clean H1→H2→H3 structure is how crawlers, screen readers, and AI parse your content.

What good looks like Headings nest in order with no skipped levels.

When the title, H1, URL, and opening line agree on the topic, relevance is unambiguous.

What good looks like The main topic appears in the title, the H1, the slug, and the first paragraph.

Alt text powers image search, gives screen-reader context, and helps machines understand the page.

What good looks like Meaningful images carry concise, descriptive alt text.

Google's crawler reads only the first 2 MB of a page's HTML and ignores the rest, so anything after that point cannot be indexed from this page. A smaller document is also less to download for any machine.

What good looks like The HTML document is comfortably inside what a crawler will read.

OG tags control the preview card when your links are shared or cited — a growing discovery surface.

What good looks like og:title, og:description, og:image and og:url are all set, declared with property=.

A sitemap speeds discovery and indexing, especially for newer pages with few inbound links.

What good looks like A valid /sitemap.xml, referenced from robots.txt, whose URLs resolve.

A soft-404 (a 200 for a missing page) confuses crawlers and can get junk indexed.

What good looks like Unknown URLs return a true 404 with a helpful page.

A lang attribute tells a machine which language the text is in, and a declared character set tells it how to decode the bytes. Without them a parser has to guess, and a guess can garble non-English text.

What good looks like A lang attribute on the html element and a declared character set, in a meta charset tag or the Content-Type header.

hreflang serves the right language/region version and prevents duplicate-content confusion.

What good looks like Valid, reciprocal hreflang tags across your language variants.

A <meta http-equiv="refresh"> redirect only happens after the page has loaded, so a machine that reads the response sees the page you are leaving, not the one you are sending it to. A server redirect tells every client where to go before it reads any content.

What good looks like Redirects are server redirects (301 or 302), not a meta refresh.