GA4 Tech Overview and Tech Details Reports

This guide is built from Google's Analytics Help articles on the Tech overview report and the Tech details report, plus the Help pages on detail reports linked below. Page-level numbers are covered in our Pages and screens report guide, and page speed in our Core Web Vitals guide.

Overview vs details

There are two reports, and they do different jobs:

• Tech overview is a set of summary cards. Google calls it "a pre-made overview report that provides an overview of the technologies people are using to access your website or app, such as their browser, device model, and screen resolution."
• Tech details is a detail report with charts and a table, which "helps you identify the technology people use to access your website or app, including their browser, screen resolution, app version, and operating system." This is the one you work in.

Neither needs any setup. Google says the overview data "is updated automatically from the web pages and app screens with the Google Analytics measurement code installed," and every dimension in Tech details is listed as "populated automatically."

Where to find them

1. Sign in to Google Analytics.
2. From the left menu, select Reports.
3. Under the User section, click Tech > Overview, or Tech > Tech details.

Google notes the Tech overview "appears on the left only in the Life cycle collection," so a property that uses the Business objectives collection will not show it by default. In both cases an Editor or Administrator can add the report to the left navigation. Our Landing page report guide walks through the Library steps.

The Tech overview cards

By default the overview has these cards, each showing active users. Editors and Administrators can change the cards, so your property may show different ones.

The Latest app release card opens a dashboard that Google says "provides the same information as what the Latest Release report provides in the Firebase console." The 30-minute card is covered in our Realtime report guide.

Dimensions in Tech details

The table can switch between these dimensions with the picker at its top left. The definitions are Google's, shortened.

Two of these are easy to misread:

• Screen resolution is the screen, not the browser window. MDN describes window.screen as an object "for inspecting properties of the screen on which the current window is being rendered." Someone on a 1920x1080 monitor with a half-width browser window still shows as 1920x1080, so do not treat this dimension as your layout breakpoints.
• Platform and Device category answer different questions. Platform says web or app. Device category says desktop, mobile or tablet. A visit to your website from a phone is Platform Web, Device category mobile.

App version only fills in for app data. If you have only a website, expect it to be empty or (not set).

Metrics in Tech details

The default table has eight metrics: Active users, New users, Engaged sessions, Engagement rate, Engaged sessions per active user, Average engagement time, Event count and Key events. Editors and Administrators can add or remove them.

The ones that matter most for comparing devices:

• Engagement rate, "engaged sessions / total sessions." An engaged session is one that "lasted 10 seconds or longer, or had 1 or more key events or 2 or more page or screen views."
• Average engagement time, the time your site "was in focus in a user's browser or an app was in the foreground," divided by active users.
• Key events, which only fill in once you have marked an event as a key event. Our key events guide covers that.

How GA4 counts users and sessions is in our users vs sessions guide.

Finding device-specific problems

Raw user counts mostly tell you your audience mix. The useful signal is a row that behaves differently from the others: one browser, OS version or device category with a much lower engagement rate or far fewer key events per user than the rest. That often points to something broken for that group, such as a form that will not submit on one browser or a menu that will not open on small phones.

The tools Google gives you in a detail report, from its About detail reports article:

• Change the dimension. Start with Device category, then Browser, then OS with version, sorting by the metric you care about.
• Add a second dimension. Google's change dimensions article says you can "add a second dimension to understand data for a combination of dimensions"; it "is added to the report temporarily, and it's removed when you leave the report." Browser plus Device category, for example, separates Safari on iPhone from Safari on Mac.
• Filter. Google's example is focusing "only on data generated by Android devices."
• Compare. Comparisons let you "evaluate subsets of your data side by side," such as Android against iOS. Our comparisons guide covers how to build them.
• Check data quality. The same article says you can see "if any of your data is hidden due to data thresholds or Google Analytics limits," which matters with long-tail dimensions such as Device model.

The Tech details report has no page dimension by default. To see which pages a device group struggles on, go the other way: open the Pages and screens report and add Device category as the second dimension.

Once a row looks wrong, the report has done its job. The fix starts with testing the site on that browser or device yourself; our website launch checklist lists the cross-device checks we run.

Tech reports vs Search Console and Core Web Vitals

The Tech reports tell you who your visitors are and how they behave by device. They do not measure speed: none of the default metrics is a loading or responsiveness time.

For speed, use the Core Web Vitals report in Search Console. Google says its data "comes from the CrUX report," which "gathers anonymized metrics about performance times from actual users visiting your URL," split by device type (desktop or mobile) over the last 28 days. Our Core Web Vitals guide explains the thresholds and how to check them.

The two fit together. If GA4 shows mobile users engaging far less than desktop users, and Search Console shows poor mobile Core Web Vitals for the same pages, slow pages are a likely cause. If mobile speed is fine, look at layout and forms instead. Do not expect the device numbers in the two tools to match: Search Console reports page requests per URL group, GA4 reports users and sessions.

Customizing the report

Editors and Administrators can change the report for everyone. Google's customize detail reports article covers adding dimensions to the picker and setting a default, changing metrics, and saving a report filter with "up to 4 more conditions" joined by AND. For a site with an app, a saved version filtered to Platform = Web keeps app traffic out of a web review. The save, template and unlink steps are the same as for the Events report; see our Events report guide.

How we use the Tech reports

This is our own practice, not Google guidance:

• Before a redesign, we pull the browser, device category and OS mix for the last few months, so testing covers what visitors actually use rather than a guess.
• After a launch, we compare engagement rate and key events by Device category and Browser against the weeks before. A drop on one row only is our first lead for a device-specific bug.
• We read small rows with care. A browser with a handful of users can show an extreme engagement rate by chance, so we look for a gap that holds over several weeks.
• We check mobile Core Web Vitals in Search Console alongside, so we know whether to look at speed or at the page itself.

Frequently asked questions

Where is the Tech details report in GA4?

Go to Reports, then Tech > Tech details under the User section. If it is missing, an Editor or Administrator can add it to the left navigation from the Library.

What is the difference between Platform and Device category?

Platform is how people reached you: Web, Android or iOS. Device category is the type of device: desktop, mobile or tablet. A website visit from a phone is Platform Web and Device category mobile.

Does screen resolution show the size of the browser window?

No. Google says it is calculated from the window.screen value, which describes the screen the window is shown on, not the window itself.

Why is App version empty in my report?

App version is the Android versionName or the iOS short bundle version, so it only has values for app data. A website-only property will not fill it in.

Can the Tech reports show page speed?

No. They show users and engagement by technology. For loading and responsiveness by device type, use the Core Web Vitals report in Search Console, which uses field data from actual visitors.

For more on measurement, see our guides to GA4 basics, the Events report, explorations and mobile app analytics.