Simo Ahava's blog

One of the hard-and-fast rules in Google Analytics is that once hits have been collected and processed into your data properties, those hits are untouchable. This means that if you mistakenly collect duplicate or incorrect transactions, PII traffic, or referral spam, for example, it’s extremely difficult, if not downright impossible, to purge or change this data in Google Analytics. Another staple of Google Analytics’ strict schema is that displacing hits in time is also very difficult. Read More…

One of the hard-and-fast rules in Google Analytics is that once hits have been collected and processed into your data properties, those hits are untouchable. This means that if you mistakenly collect duplicate or incorrect transactions, PII traffic, or referral spam, for example, it’s extremely difficult, if not downright impossible, to purge or change this data in Google Analytics. Another staple of Google Analytics’ strict schema is that displacing hits in time is also very difficult. Read More…

Until recently, I had a feature on GTM Tools that polled the user’s Google Tag Manager container(s) for a recently published version. If one was found, a notification was sent to a Slack app, which forwarded it to a workspace and channel of the user’s choice. This was fine, except for the fact that polling the GTM and Slack APIs for dozens upon dozens of containers is a total resource hog, and the only way I can maintain GTM Tools is it doesn’t have API leaks like that. Read More…

Updated 25 May 2021: Added information about using this with GA4. As Google Analytics 4 does not have a mechanism to disable cookie storage, only the second solution (send dataLayer events from iframe to the parent) described in this article will work for GA4. Here I am, back with <iframe> and cross-domain tracking. I’ve published a couple of articles before on the topic, with my upgraded solution being the most recent one. Read More…

Update 6 April 2020: I updated the template in the gallery to the latest version of the IP Geolocation API SDK, which no longer requires jQuery. Also, the SDK now handles API request caching to browser storage automatically, so the “Enable Session Storage” option was added to the template. Google Analytics had been foreshadowing the deprecation of the Network Domain and Service Provider custom dimensions since late 2019. On February 4, the plug was finally pulled, and both these dimensions started flatlining to (not set) in Google Analytics reports. Read More…

One of the most prominent features of Google Tag Manager since the dawn of time (actually, late 2012) is the Custom HTML tag. This little piece of magic lets Google Tag Manager inject an HTML element to the page. Since time immemorial (still late 2012), it’s allowed us to turn Google Tag Manager from a sandboxed prisoner of the native tag templates to a no-holds-barred client-side content management solution. In this article, we’ll discuss how the Custom HTML tag works, and what you might be tempted to use it for. Read More…

One of the prime things to use Google Tag Manager for is script injection. Loading a third-party JavaScript library is trivial to do with a Custom HTML tag, and works like a charm. However, using Custom HTML tags for, well, anything, is no longer the preferred way to add custom code to the site. Custom HTML tags are pretty expensive DOM injections, and they can be incredibly dangerous tools (for UX, security, and privacy) in the wrong and/or inexperienced hands. Read More…

Update 6 April 2020: I updated the template in the gallery to the latest version of the IP Geolocation API SDK, which no longer requires jQuery. Also, the SDK now handles API request caching to browser storage automatically, so the “Enable Session Storage” option was added to the template. My latest custom tag template tackles a use case I’ve referred to a number of times before, especially in my article on sending weather data to Google Analytics. Read More…

Update 17 February 2020: Google Tag Manager’s Preview mode cookies have been updated with the necessary flags, so they will not break once SameSite enforcement begins. If you’ve opened the browser console in Google Chrome (since Chrome 76), you might have seen a bunch of warnings in a yellow background related to something called a SameSite cookie attribute that is either missing or incompletely set for cookies set on external domains. Read More…

Universal Analytics utilizes two components (by default) to attribute a browser session to a specific campaign: query parameters in the URL and the referrer string. The page URL is sent with every hit to Google Analytics using the Document location field, which also translates to the &dl parameter in the Measurement Protocol. The referrer string is sent with a hit to Google Analytics using the Document referrer field, as long as the referrer hostname does not exactly match that of the current page and the referrer string is not empty. Read More…

Google Tag Manager now lets you add unit tests directly to your custom templates. This is useful, since it allows you to control the code stability of your templates, especially if you’ve decided to share those templates with the public. I recently shared a general guide for how template tests work, but I wanted to expand the topic a little, and share with you two walkthroughs of custom template tests: one for a variable template and one for a tag template. Read More…