How to Detect and Track Incognito Users with Google Analytics and Google Tag Manager

<script>
(function (cb) {
    var db,
    on = cb.bind(null, 'true'),
    off = cb.bind(null, 'false')

    function tryls() {
        try {
            localStorage.length ? off() : (localStorage.x = 1, localStorage.removeItem("x"), off());
        } catch (e) {
            // Safari only enables cookie in private mode
            // if cookie is disabled then all client side storage is disabled
            // if all client side storage is disabled, then there is no point
            // in using private mode
            navigator.cookieEnabled ? on() : off();
        }
    }

    // Blink (chrome & opera)
    window.webkitRequestFileSystem ? webkitRequestFileSystem(0, 0, off, on)
    // FF
    : "MozAppearance" in document.documentElement.style ? navigator.serviceWorker ? off() : on()
    // Safari
    : /constructor/i.test(window.HTMLElement) || window.safari ? tryls()
    // IE10+ & edge
    : !window.indexedDB && (window.PointerEvent || window.MSPointerEvent) ? on()
    // Rest
    : off()
})(function (isPrivateMode) { window.dataLayer.push({event: 'detected_incognito', is_incognito: isPrivateMode}); });
</script>

Credit: This code is a slightly modified version of the snippet posted on Stack Overflow by the user Endless. Works in the following browsers:

• Chrome
• Firefox
• Safari
• IE 10+
• Edge

Google Tag Manager Data Layer variable

Name: DLV - Is Incognito Data Layer Variable Name: is_incognito Data Layer Version: Version 2

Google Tag Manager Custom Event trigger

Name: CE - Detected Incognito Event name: detected_incognito This trigger fires on: All Custom Events

Google Tag Manager Google Analytics tag

Name: UA - Is Incognito Browser Type: Event Category: browser_info Action: incognito Label: {{DLV - Is Incognito}} Non-Ineraction Hit: True

Bonus: sending data to a custom dimension

The previous setup sends incognito usage info to Google Analytics as a custom event. In some cases, having it as a custom dimension could be more useful. Here's how you set that up.

1. Go to Admin panel of your Google Analytics account
2. In property settings, choose Custom Dimensions under Custom Definitions
3. Add a new Custom Dimension

Name: Is Incognito Scope: Session Now, remember the index your newly created dimension has. In our case, it is 12. Modify your Google Tag Manager tag "UA - Is Incognito Browser" to include a Custom Dimension and set its value equal to {{DLV - Is Incognito}}.

Using this in reports

Congratulations! If you did everything correctly, you will soon see data about incognito users flowing into Google Analytics. There are several ways how you can include this data in your reports but perhaps you will find using it in custom segments the most useful. This allows you to see how regular vs incognito users perform based on any metric you track in Google Analytics. Also, you could build all kinds of custom reports. Here's a very basic one that's good for testing if your setup works as expected.

And here's how it will look like.

As we can see from the custom report above, our demo site received 794 sessions, out of which 4.3% came from browsers turned into incognito mode.

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That's it - now you have information about users that have turned their browser into incognito or private mode and how big impact they might have on your metrics and A/B testing program. If you have any questions or ideas for improvement, please let us know in the comments below.