Technical SEO ensures search engines can correctly crawl and index your site - it covers page speed, mobile usability, XML sitemaps, robots.txt, duplicate content, structured data, and Core Web Vitals. On-page SEO optimises individual pages for target keywords - title tags, headings, content depth, internal linking, and image alt text. Off-page SEO builds domain authority through external signals - primarily backlinks from trusted sites, brand mentions, and digital PR. Technical SEO requires a well-maintained website and hosting infrastructure - a site that goes down frequently or loads slowly will never rank well regardless of content quality.