Core Web Vitals are three specific performance metrics Google uses as ranking factors. LCP measures how long the largest visible element takes to load (aim for under 2.5 seconds). FID measures the delay between a user's first interaction and the browser's response (target under 100 milliseconds). CLS quantifies unexpected layout shifts that make users accidentally click the wrong thing (keep it below 0.1). Google officially rolled these into ranking algorithms in 2021, though their weight isn't massive compared to content relevance and backlinks. Still, when competitors have similar authority, better Core Web Vitals can tip the scales. The metrics appear in Google Search Console under the Experience section and in PageSpeed Insights. LCP typically breaks due to unoptimized hero images, render-blocking CSS, or slow server response times. We see hosting make a 40-60% difference here—cheap shared hosts in the U.S. serving Canadian traffic often blow past 4 seconds, while a properly configured VPS or CDN gets you under 2 seconds consistently. Image formats matter too: WebP cuts file sizes by 25-35% versus JPEG without visible quality loss. FID is being replaced by Interaction to Next Paint (INP) in March 2024, which measures overall responsiveness instead of just the first click. Heavy JavaScript frameworks and third-party scripts are the usual culprits. If you're loading ten tracking pixels and a chatbot on first paint, you're cooked. CLS problems come from images without width/height attributes, ads that push content down, or web fonts that cause text reflow. Reserving space for dynamic elements before they load fixes most issues. At Ottawa SEO, we run Lighthouse audits during every site build and set up monitoring through services like Calibre or SpeedCurve for client sites where performance directly impacts revenue. For local service businesses, fixing Core Web Vitals rarely moves the needle as much as getting ten more GMB reviews, but for e-commerce or sites competing nationally, it's table stakes. Measure on actual devices using Chrome DevTools or real user monitoring—lab scores don't always reflect what users in Winnipeg on 4G experience.