How to block Google Analytics from tracking specific query parameters?

Question

I have a URL like example.com/?fname=John&lname=Doe&id=1234

How can I stop Google Analytics from tracking the parameter names, fname and lname?

Answer 1

Admin -> Profile -> Profile settings -> Exclude URL Query Parameters (enter your parameters as a comma separated list).

Answer 2

In GA4, there is no longer a designated field for excluding query parameters. We need to distinguish between two methods of implementing GA4 first:

• with gtag.js
• with Google Tag Manager (running a GA4 Tag inside)

Solution for gtag.js

• add a <script>...</script> tag before the Google Analytics snippet that defines the cleanPageLocation() function. Next, add the function to the GA4 snippet (see below)
• the function will remove fname and lname but keep id
• otherwise to exclude other params update the excludeStrings array

cleanPageLocation() function

<script>
function cleanPageLocation() {
// define parameters to exclude
var excludeStrings = [
    "fname",
    "lname"
];
var addressString = new URL(document.location);
var queryString = addressString.search;

// check if query string holds any parameters, otherwise just return the url without them
if (queryString.indexOf("?") != -1) {
    // https://stackoverflow.com/questions/901115/how-can-i-get-query-string-values-in-javascript
    var getQueryParamsFromURL = function getQueryParamsFromURL() {
        var match,
            search = /([^&=]+)=?([^&]*)/g,
            decode = function decode(s) {
                return decodeURIComponent(s);
            },
            query = addressString.search.substring(1);

        var urlParams = {};

        while ((match = search.exec(query))) {
            urlParams[decode(match[1])] = decode(match[2]);
        }

        return urlParams;
    };
    // create param object from query string
    var urlParams = getQueryParamsFromURL();

    // if it holds any of the defined parameters, remove the key and keep the rest
    Object.keys(urlParams).map(function (key) {
        if (excludeStrings.includes(key)) delete urlParams[key];
    });

    // Create filtered query string
    var queryString = new URLSearchParams(urlParams).toString();

    // add ? to querystring unless it's empty
    if (queryString != "") queryString = "?" + queryString;
}

// return cleaned URL
return addressString.origin + addressString.pathname + queryString;
}
</script>

Now add the function to the Google Analytics Snippet

• assign it to the page_location parameter

<!-- Global site tag (gtag.js) - Google Analytics -->
<script async src="https://www.googletagmanager.com/gtag/js?id=...your id..."> 
</script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date());
  gtag('config', 'YOUR-ID-HERE', {
    'page_location': cleanPageLocation(),
  });
</script>

Solution for Google Tag Manager

• in GTM create a custom JS variable with the function returning being the same as above, just that its an anonymous function, as required by GTM

function() {
// define parameters to exclude
var excludeStrings = [
    "Go_Away"
];
var addressString = new URL(document.location);
var queryString = addressString.search;

// check if query string holds any parameters, otherwise just return the url without them
if (queryString.indexOf("?") != -1) {
    // https://stackoverflow.com/questions/901115/how-can-i-get-query-string-values-in-javascript
    var getQueryParamsFromURL = function getQueryParamsFromURL() {
        var match,
            search = /([^&=]+)=?([^&]*)/g,
            decode = function decode(s) {
                return decodeURIComponent(s);
            },
            query = addressString.search.substring(1);

        var urlParams = {};

        while ((match = search.exec(query))) {
            urlParams[decode(match[1])] = decode(match[2]);
        }

        return urlParams;
    };
    // create param object from query string
    var urlParams = getQueryParamsFromURL();

    // if it holds any of the defined parameters, remove the key and keep the rest
    Object.keys(urlParams).map(function (key) {
        if (excludeStrings.includes(key)) delete urlParams[key];
    });

    // Create filtered query string
    var queryString = new URLSearchParams(urlParams).toString();

    // add ? to querystring unless it's empty
    if (queryString != "") queryString = "?" + queryString;
}

// return cleaned URL
return addressString.origin + addressString.pathname + queryString;
}

• afterwards add the JS variable as value to the GA4 config tags field page_location

more details for GTM: https://bluerivermountains.com/en/ga4-query-parameter-exclusion