SEO glossary · Updated
What is technical SEO?
Technical SEO is making sure search engines can crawl, render and index your pages, and index the right version of each one.
Founder, SEO·AEO·GEO
Builds SEO·AEO·GEO and writes the crawler, schema, and citation research published here.
Technical SEO is the part of SEO that deals with how your site works rather than what it says: whether search engines can reach your pages, read them, store them in their index and pick the right version of each. If technical SEO fails, the best content in the world won't rank.
Google's own technical requirements are short: Googlebot isn't blocked, the page works (it returns HTTP 200), and the page has indexable content. Technical SEO is everything that keeps those three true across a whole site.
What technical SEO covers
| Area | Examples |
|---|---|
| Crawling | robots.txt, firewalls and CDNs, internal links, XML sitemaps, crawl budget on large sites |
| Rendering | Content that depends on JavaScript, server-side rendering, lazy loading |
| Indexing | noindex tags, status codes, soft 404s, duplicate content, canonical tags |
| Site structure | URL structure, navigation, breadcrumbs, pagination |
| Performance | Server response time, Core Web Vitals, image sizes |
| Mobile | Viewport, responsive layout, mobile-first indexing |
| Security | HTTPS, security headers, no hacked content |
| Structured data | JSON-LD that describes the page |
| International | hreflang, language and country targeting |
Technical SEO for AI search
AI search adds three technical checks. AI crawlers such as OAI-SearchBot, Claude-SearchBot and PerplexityBot need to be allowed by robots.txt and not blocked by your firewall. They don't run JavaScript, so content has to be in the HTML. And snippet controls such as nosnippet stop your text being quoted, including in Google's AI Overviews.
The most common technical problems
- A noindex tag left on after a site launch.
- Canonical tags pointing at the wrong page, often the homepage.
- robots.txt or a firewall blocking crawlers by accident.
- Text or links that only appear after JavaScript runs.
- No sitemap, or a sitemap full of redirected and missing URLs.
- Slow server responses and oversized images.
Check it on your own site
What the free audit tests for this
- robots.txt rules
- Edge access
- Indexability
- Raw HTML visibility
- Canonical
- HTTPS
- Soft 404
- Load time
- sitemap.xml
One URL, about 20 seconds, no login. You get the result of every check and the exact fix for the top three issues.
Audit your website freeFAQ
Is technical SEO hard?+
The basics aren't: most sites need a sitemap, correct robots rules, HTTPS, correct canonicals and fast pages. Large sites, migrations and JavaScript-heavy apps are where it gets technical.
Do I need a developer for technical SEO?+
For finding problems, no; free tools and Search Console show most of them. For fixing them on a custom-built site, usually yes.
How is technical SEO different from on-page SEO?+
Technical SEO makes pages crawlable and indexable; on-page SEO makes their content clear and useful. A page needs both.
Sources
- Google Search technical requirements — Google Search Central
- Introduction to robots.txt — Google Search Central
- Understand JavaScript SEO basics — Google Search Central
- How to specify a canonical URL — Google Search Central
- Understanding Core Web Vitals and Google search results — Google Search Central