google-analytics-4

# Google Analytics 4 Implementation Guide > Applies to: Any website or web app | Updated: February 2026 A practical guide for implementing Google Analytics 4 (GA4) - covering installation, critical first-time setup, event tracking, e-commerce, consent, and advanced topics. Written for AI coding assistants: skip sections that don't apply to the user's setup. > **Note:** Universal Analytics (UA / GA3) was fully sunset in 2024. GA4 is the only current Google Analytics product. --- ## Section 0: Before You Start Answer these questions before writing any code. They determine which sections apply. **Q: Are any of your visitors in Europe (EU/EEA) or the UK?** Default: no - if yes, Consent Mode v2 setup is required (see [Consent Mode v2](#consent-mode-v2)) **Q: Do you run Google Ads (search, display, YouTube, or Shopping)?** Default: no - if yes, ad consent signals matter for conversion tracking and which events you mark as conversions **Q: Is your site a single-page app (React, Vue, Angular, Next.js, etc.) where the URL changes without a full page reload?** Default: check the project for `package.json`, `next.config.*`, `vite.config.*`, `angular.json`, or `nuxt.config.*` - if found, assume SPA and apply the [Single-Page Apps](#single-page-apps) section automatically **Q: Do you need to track purchases or sales?** Default: no - skip [E-commerce Tracking](#e-commerce-tracking) if no **Q: Do you already have a GA4 property, or is this a fresh start?** Default: fres...