Technical SEO breaks down into six foundational components that determine whether search engines can find, understand, and rank your content effectively. Crawlability covers everything that helps or blocks search bots from accessing your pages. This includes robots.txt configuration, XML sitemaps, server response codes, and crawl budget management. A single misconfigured robots.txt line can tank an entire site's visibility overnight. Indexability ensures pages that should rank actually get stored in Google's index. Canonical tags, noindex directives, duplicate content handling, and HTTPS implementation all fall here. We regularly see sites with 10,000 pages but only 800 indexed because of canonical chaos or accidental noindex tags leftover from staging. Site architecture is your URL structure, internal linking hierarchy, and navigation logic. Flat architectures (homepage to target page in 2-3 clicks) typically outperform deep nests. Clean URLs beat parameter-heavy strings for both bots and users. Page speed now directly impacts rankings through Core Web Vitals: Largest Contentful Paint, First Input Delay, and Cumulative Layout Shift. We aim for LCP under 2.5 seconds, FID under 100ms, and CLS under 0.1. Real-world improvement often means image optimization, lazy loading, and cutting render-blocking JavaScript. Mobile optimization isn't optional since Google's mobile-first indexing treats your mobile version as the primary source. Responsive design, touch-friendly interfaces, and avoiding intrusive interstitials are baseline requirements now. Structured data uses schema.org markup to tell search engines what your content represents—products, reviews, events, local businesses, FAQs. Properly implemented, it unlocks rich snippets, knowledge panels, and featured positions that dramatically improve click-through rates. At Ottawa SEO, we audit these six components systematically using Screaming Frog, Google Search Console, and PageSpeed Insights. Most sites have 15-30 fixable technical issues costing them 20-40% of potential organic traffic. The wins aren't sexy, but they're measurable and they compound over time.