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Google Analytics 4 (GA4)
November 01, 2026 Google Analytics 4 (GA4) is the current version of Google Analytics. It measures user behavior with events across both websites and apps in a single property, and it replaced Universal Analytics (UA), which stopped processing data on July 1, 2023.
What is GA4?
Google describes GA4 as a property type that collects event-based data from both websites and apps to better understand the customer journey. It includes privacy controls such as cookieless measurement and behavioral and key event modeling, plus direct integrations with media platforms (Analytics Help, Introducing the next generation of Google Analytics, accessed November 2026). The modeling for users who decline cookies is tied to Consent Mode.
How GA4 replaced Universal Analytics
- March 2023: for UA properties that had not migrated or opted out, Google created a GA4 property automatically.
- July 1, 2023: standard UA properties stopped processing new data.
- July 1, 2024: the UA 360 extension ended; that week all users lost access to UA data in the interface and the API, and the data was deleted.
UA properties had IDs starting with “UA-” followed by numbers, such as UA-000000-1 (Analytics Help, Google Analytics 4 has replaced Universal Analytics, accessed November 2026). Any old reports not exported before July 2024 cannot be recovered.
Events and key events in GA4
An event measures an interaction or occurrence on a site or app: a page load, a link click, a purchase, an app crash. GA4 groups events into 4 types (Analytics Help, About events, accessed November 2026):
| Type | Meaning |
|---|---|
| Automatically collected | Collected as soon as GA4 is installed, such as page_view and session_start |
| Enhanced measurement | Collected when enhanced measurement is on, such as scrolls and outbound clicks |
| Recommended | You implement them, but with names and parameters Google predefines, such as purchase and generate_lead |
| Custom | You name them; they do not show in most standard reports, so you need custom reports or Explorations |
A key event is an event that matters to your business and that you mark as such, like generate_lead or purchase. Any event can be marked. To check your setup, use the Realtime card (events from the last 30 minutes) or DebugView. The no-code way to add events is Google Tag Manager.
GA4 data retention
Standard GA4 lets you keep user-level data for 2 or 14 months; event data is also 2 or 14 months, with Analytics 360 going up to 26, 38 or 50 months. Retention only affects Explorations and funnel reports, not standard aggregated reports. Age, gender and interest data is always kept for 2 months (Analytics Help, Data retention, accessed November 2026).
Do this as soon as you create a property: go to Admin, Data retention and choose 14 months. Leave it at 2 months and next year you cannot open an Exploration comparing this year’s Tet season with last year’s.
Example: reading channel performance in GA4 (hypothetical)
A shop marks purchase as a key event. In October, Google Ads brings 2,000 sessions and 40 orders, a 2% conversion rate. Facebook brings 3,000 sessions and 30 orders, a 1% rate. At VND 20 million per channel, cost per order is VND 500,000 for Google Ads and about VND 666,667 for Facebook. The comparison only holds if Facebook links carry clean UTM parameters; without them, many Facebook sessions get attributed to the wrong source.
Frequently asked questions
Is GA4 free?
The standard version is free. Google Analytics 360 is the paid version, with higher data limits and longer retention.
Does GA4 replace server-side tracking?
No, they work together: GA4 receives and reports the data, while server-side tracking is a more reliable way to send that data when cookies are blocked. See our guide to server-side tracking and marketing analytics.
If you need events, key events and the GA4 to Google Ads link rebuilt, contact Adtek.
