What technical SEO includes, explained in plain English
A plain-English guide to technical SEO: crawling, indexing, site speed, Core Web Vitals, redirects, canonical tags, sitemaps and structured data.
Summary
Technical SEO is the work that makes a website easy for search engines to crawl, render, understand and index. It covers crawl access, indexation rules, site speed and Core Web Vitals, mobile usability, redirects, canonical tags, XML sitemaps, structured data, security and site architecture. It supports content; it does not replace it.
Crawling: can search engines reach your pages?
Search engines discover pages by following links and reading sitemaps. A robots.txt file tells crawlers which areas to avoid. Mistakes here, such as blocking an entire site after a redesign, can remove pages from search entirely.
- Important pages linked from other pages on the site
- A clean robots.txt that does not block key content
- An XML sitemap listing canonical, indexable URLs
Indexing: should each page appear in search?
Not every page should be indexed. Thank-you pages, internal search results and test pages are usually excluded with a noindex rule. Canonical tags tell search engines which version of similar pages is the preferred one, preventing duplicate content problems.
Speed and Core Web Vitals
Core Web Vitals are Google’s measures of real-user experience:
| Metric | What it measures | Good threshold |
|---|---|---|
| Largest Contentful Paint (LCP) | How quickly main content loads | 2.5 seconds or less |
| Interaction to Next Paint (INP) | How quickly the page responds to input | 200 milliseconds or less |
| Cumulative Layout Shift (CLS) | How much the layout unexpectedly moves | 0.1 or less |
Optimised images, less JavaScript, efficient fonts and good hosting all contribute.
Redirects, status codes and site moves
When pages move, a permanent (301) redirect sends users and search engines to the new address. Missing redirects create broken links; chains of several redirects waste crawl effort. Site migrations need a complete redirect map prepared before launch.
Structured data and site architecture
Structured data is code, usually JSON-LD, that describes page content in a standard vocabulary such as Schema.org. It helps search engines understand organisations, services, articles and FAQs. It must match the visible content on the page.
Site architecture is how pages are grouped and linked. A logical hierarchy, descriptive URLs and breadcrumbs help both users and search engines understand relationships between topics.
How to know if you need a technical SEO audit
- Organic traffic dropped after a redesign or migration
- Pages are missing from search results
- Search Console reports indexing or Core Web Vitals issues
- You are about to launch or rebuild a website
Key takeaways
- Crawling and indexing come first
- Speed and stability affect users and search
- Structured data clarifies meaning
- Technical SEO enables content to perform
Related services
This article is general guidance, not advice for a specific situation. Platform features and policies change; details were checked on the review date above.