Google Analytics is the most widely used web analytics platform, free for most businesses. GA4 tracks website traffic, user behaviour, conversions, and audience demographics — critical data for any UK startup. Note: Google Analytics requires a GDPR-compliant cookie consent banner under UK PECR regulations. Many UK businesses now pair GA4 with a privacy-friendly tool like Plausible for cookieless tracking. Integrates with Google Ads, Search Console, and BigQuery.