SEO Basics

What is SEO?

Understanding search engine optimization, how search engines index your site and why it matters.

⏱ 4 min read · Updated on 22 April 2026

Definition

SEO (Search Engine Optimization) refers to all the techniques used to improve the visibility of a website in the organic (non-paid) results of search engines like Google, Bing or DuckDuckGo.

How a search engine works

  1. Crawling — Robots (called spiders) browse the web by following hyperlinks.
  2. Indexing — Discovered pages are analyzed and stored in a massive index.
  3. Ranking — When a query is submitted, the algorithm evaluates hundreds of criteria to rank pages by relevance.

The 3 pillars of SEO

Pillar Description
Technical Speed, crawlability, mobile, HTTPS, structured data
Content Quality, relevance, keyword coverage
Authority Number and quality of inbound links (backlinks)

What Crawlibri measures

Crawlibri primarily covers the technical pillar: it analyzes each page to detect issues that impact indexing and rankings.

Key takeaway: A good Crawlibri health score is a necessary but not sufficient condition for good rankings. Content and authority matter just as much.

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