Core Web Vitals and page speed metrics
Every Core Web Vital and supporting speed metric in one place: LCP, INP, CLS, FCP, TBT, TTFB, what each threshold means, and how to diagnose a bad score.
Glossary
Quick definitions for common SEO, performance, and web terms.
DNS records explained: A, AAAA, CNAME, MX, NS, TXT, CAA
Every DNS record type that matters for a website, what breaks when each one is wrong, how TTL controls propagation, and how DNSSEC protects the whole chain.
On-page SEO: meta tags, headings, and structured data
Meta descriptions, heading structure, keywords, structured data, Open Graph, E-E-A-T, backlinks, and engagement metrics — what each one does and what it does not.
Technical SEO: crawling, indexing, and redirects
How search engines crawl and index a site: robots.txt, sitemaps, canonical tags, noindex, redirects and status codes, hreflang, crawl budget, and llms.txt.
WCAG and web accessibility
What WCAG is, what levels A, AA and AAA require, how the POUR principles are organised, what ARIA does, and which parts of conformance a tool can and cannot check.
Web performance: delivery, caching, and uptime
How bytes actually reach a browser: compression, CDNs, HTTP/2 and HTTP/3, lazy loading, and uptime monitoring — with the config that makes each one work.
Web security: HTTPS, headers, and common attacks
The security headers every site should send, the attacks they defend against — XSS, CSRF, clickjacking, SQL injection — and how SPF, DKIM, and DMARC stop domain spoofing.