The analyst’s toolbelt: Essential Chrome extensions

Chrome Extensions have been available since 2010, changing the way each of us use our browsers and making each one unique to the user. Throughout my career, colleagues have shared different extensions that have helped me work more efficiently and I thought it only fair to share my favourites with fellow analysts.

The first problem we will be looking to solve is how to test and debug analytics set-ups whilst browsing sites. There are a few different extensions that can support this task and which one to use will all depend on personal preferences. We’ll start with some of the most popular, before moving onto the lesser-known – and in my experience more powerful! – extensions for Google Chrome.

Debugging and Testing

Google Analytics Debugger

This extension was one of the first to be released and is developed by the Google Analytics team. It’s actually very simple: requests for the ‘analytics.js’ library are automatically converted to the ‘analytics_debug.js’ version, meaning that useful messages are printed to the JavaScript console as hits are generated. This enables you to diagnose issues with hit type, custom dimensions, content groupings, and so on.

Google Analytics Debugger

While it’s definitely one to keep installed, I personally don’t use this extension that often. It’s fairly limited in scope, and its reliance on the console makes it less flexible that some of the other tools in this list.

Tag Assistant

Tag Assistant is also developed by Google. This extensions gives us the ability to record an entire sequence of pageviews, meaning that it’s great for testing user journeys and debugging sessions. At the end, your recording is available as a user-friendly report that can be exported.

Tag Assistant

Unlike the Google Analytics Debugger, Tag Assistant also works with GTM and other Google  Marketing Tags. Its main downside is that it hasn’t been kept up-to-date – I’ve recently experienced the occasional crash, and its warning messages about non-standard implementations seem to occur at random.

Observepoint Tag Debugger

This is one of my favourite extensions. It’s the one I recommend to anyone wanting to understand tracking in more granular detail. ObservePoint, unlike Google Analytics Debugger, adds its own tab on to the Dev Tools, keeping it tidy and easy to access.

Observepoint Tag Debugger

You can click into different tags to get a detailed breakdown of all the variables that are being collected such as Tracking ID, Custom Dimensions and Content Groupings for Google Analytics. The tags are also displayed in real-time, meaning you can test event tracking with ease.

Another feature of ObservePoint is it displays all marketing, advertising and analytics tags. This can be extremely useful to show any rogue tracking on a site but can be messy when you are just trying to debug your GA tracking. Luckily the team have thought about this, with the option to select to only look at specific categories of tags by going to the extension options.


Ghostery has been around for a long time and like ObservePoint is useful for giving an overview of all trackers and tags on a website. The unique feature of Ghostery is the ability to block certain types of tags from firing on your browser, allowing you to become a ghost. I find this useful when testing client’s websites as I can block tags from firing if an IP filter hasn’t been set up yet. The disadvantage of Ghostery is unlike Observepoint it doesn’t give you the ability to look at a tag in detail.


When you see a tag you are unsure about, Ghostery gives you the ability to understand more such as what the company behind it is about, their affiliations and privacy contact.

Tag Manager Injector

This extension is very simple but can be extremely useful. It allows you to inject a GTM container on to any site by adding the GTM container ID.

Tag Manager Injector

It comes in useful when you are waiting for GTM to be added to the site, allowing you to start building out the container before GTM is even in place. You can also push a mock data layer allowing you to start creating variables and mapping these into GTM.

General Auditing

In order to make practical recommendations or to accurately scope a project, it’s vital that your understanding of the site extends beyond the surface-level implementation of tracking code.  A thorough understanding of a site’s architecture, build, and current performance are immensely valuable. Here I’ve collected some of the more general-purpose extensions that have helped me in this regard.


This is an extension I only discovered recently but has already become one of my favourites. When you visit any website, Whatruns will breakdown (an approximation of) the technology that makes it run.


This is very useful when scoping a website as it gives you a good overview of what makes it tick.


SimilarWeb has been around for a long time and the extension is an easy way to get quick insight into a website’s approximate performance. The figures aren’t exact but gives you a estimate of traffic, website ranking, geographic and traffic source breakdown. If you are interested in understanding where this data comes from, give this page by SimilarWeb a read.

Page Analytics

If you are analysing a website and already have access to the Google Analytics property, this extension is a great tool to quickly marry up insights with the page you’re currently looking at.

Page Analysis

It displays pageviews, unique pageviews, average time on page, bounce rate and exit rate by default but these can be updated with most page level metrics. There is also the ability to apply segments and even see in real-time how many users are on the site.

One of the unique features of this tool is its ability to show click patterns. Note that this is based entirely on the ‘Page’ dimension of the subsequent hit; if two CTAs have the same destination page as one another, you will see same percentage for each.

Dev Tools

Now I know this isn’t an extension but hear me out! The development tools built into modern browsers are not only incredibly powerful but are frequently updated with new features. These tools are sometimes overlooked by analysts; you might assume that a particular task requires an extension when in fact in can be accomplished with native functionality. Since we are talking about Chrome Extensions, we will stick to looking at the Chrome DevTools, I recommend following Chrome DevTools on Twitter and checking the release notes! Firefox DevTools are also worth checking out and documentation can be found here.

These tools are deserving of a complete guide in their own right, so for now, I’ve just picked a few examples of how I frequently use them.

The Elements panel is used to view and change the DOM and CSS. Unlike the raw page source, the elements panel displays the DOM; this means it reflects any changes which have been made with JavaScript. This can be used to check that your custom HTML tags in GTM have been injected correctly.

Elements Panel

The Network panel lets you view and debug network activity on a page. I commonly use this to monitor requests for specific resources, such as the Universal Analytics tag and look at the variables being set:

network panel

The Application panel is where you can inspect cookies, local and session storage, and service workers. This is how I quickly check the client ID which has been set in the _ga cookie:

application panel

Finally, the Console is where you can run JavaScript and watch for messages logged from your scripts. A common use for analysts is inspecting the Data Layer created by GTM, by which I mean the actual JavaScript array rather than GTM’s own abstracted data model.


If you’re interested in discovering more extensions, check out our post on the 10 best browser extensions for SEOs by our Senior SEO Executive, William Kay.

Hopefully this round-up has helped you discover some new extensions to use. Obviously this isn’t a comprehensive list, so if there are any extension you’d like to recommend, please let me know in the comment section below.

Comments are closed.

  • Great Post Richard,

    Another very useful tool is the Web Developer extension for chrome that lets you activate or deactivate anything in the code in one click only.

    I think it would be great if you also talked about built-in functions like the Lighthouse site audit.

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