Technical SEO basics — Core Web Vitals and page speed

What is technical SEO?

Technical SEO optimizes a website's infrastructure so search engines can crawl and index it efficiently — covering site speed, schema, the sitemap, robots.txt, and more.¹

Scope covered in this course: Core Web Vitals (page speed), schema markup, sitemap optimization, and .htaccess/robots.txt.

Core Web Vitals

Google's key metrics for user experience:

1. LCP (Largest Contentful Paint) — measures loading performance. Ideal: under 2.5 seconds.
2. INP (Interaction to Next Paint) — measures interactivity. Ideal: under 200ms.
3. CLS (Cumulative Layout Shift) — measures visual stability. Ideal: under 0.1. To avoid CLS, define fixed sizes for elements like images and ads.

Tool: Google PageSpeed Insights checks all three.

Fixing page speed

• Reduce rendering blockers — fix render-blocking JavaScript and CSS; load only what's needed.
• Remove unused code — strip unused CSS/JS; load only what each page actually requires.
• Enable caching — reduces repeated load times. Recommended plugins: LiteSpeed Cache, or WP Rocket.
• Convert images to WebP — smaller file size, faster load. Use a WebP converter plugin: install it, import a preset (or use defaults), and convert images automatically.
• File optimization — combine multiple CSS/JS files to cut the number of requests; use preload, defer, or async attributes deliberately.
• robots.txt and .htaccess — use robots.txt to control crawler access, and .htaccess for caching, redirection, and security configuration.

Summary

Applying a pre-built settings file

A ready-made caching-plugin settings file can be imported directly: install the plugin (LiteSpeed Cache or WP Rocket), open its Import option, and import the provided file — this applies every setting automatically, with no manual configuration needed.

Footnotes

1. iSkills SEO course notes, compiled 2025. ↩