Tag auditing is used to identify various tags (tag is a piece of JavaScript code) on a website for the purpose of:

• Upgrading from Classic Google Analytics to Universal Analytics
• Migrating Classic / Universal Analytics tags & configurations to Google Tag Manager.
• Debugging various Google Analytics tracking code issues
• Identifying and removing tags that no longer serve the purpose and should be removed in order to clean the website code.
• Migrating non-Google tags (like Facebook tags, Omniture tags) to Google Tag Manager.

In tag auditing we identify all the tags currently being deployed on a website. It doesn’t matter whether these tags fire or not. They need to be identified and then updated, migrated or removed.

There are 3 methods through which you can identify various tags on a website:

1. Tag auditing tools
2. Manually
3. Website scraper tools

Tag Auditing Tools

There are various free and paid tag auditing tools available in the market.

The one which I frequently use are:

1. Google Tag Assistant
2. Ghostery

Google Tag Assistant is a chrome extension through which you can identify and validate the implementation of various Google Tags fired on a web page.

However, there are three shortcomings of Google Tag Assistant:

1. It can’t identify and validate tags across a website.
2. It doesn’t work for non-Google tags
3. It can’t identify tags which don’t fire (as they are either broken or waiting for an event to occur first)

Ghostery is a chrome extension through which you can identify all the tags (both google and non-Google) which fire on a web page.

This extension also lets you block tags which could be useful in debugging tracking issues:

Just like Google Tag Assistant, it has its own shortcomings:

• It can’t identify tags across a website.
• It can’t identify tags which don’t fire (as they are either broken or waiting for an event to occur first)

Manual Tag Auditing

I manually search for a tag on a web page if its not picked up by Google Tag Assistant or Ghostery. Generally, this happens when a tag is broken and thus can not be fired on page load.

For example, if your GTM container code is broken (maybe due to formatting issues) then it won’t be picked up by Google Tag Assistant. In that case, you look into the source code of the page, search for ‘gtm.js’ file to find the location of GTM container code and determine what is wrong with the code.

I also do manual tag auditing while diagnosing ecommerce tracking issues.

Generally, ecommerce tracking code is placed on order confirmation page which can not be accessed directly through any third party tag auditing tool or website scraper.

In fact, any web page which is hidden behind a login or some sort of authentication system can not be scanned by any third-party tool and manual auditing is required.

Website Scraper Tools

Website scraper tools like Screaming Frog SEO spider can be used to identify tags across a website of any size.

I use Screaming Frog for tag auditing and for diagnosing tracking issues. Don’t be fooled by its name. It is much more than an SEO tool.

It is a powerful website crawler through which you can identify any piece of code (and its occurrences) across a website of any size and it is not very expensive either. There are other better alternatives to Screaming Frog, when it comes to tag auditing but they will cost you thousands of dollars a year, a price not many are ready to pay.

Also, no paid tag auditing tool I know is able to audit Google Analytics tags the way I am going to show you in the next few minutes.

My tag auditing system will help you in identifying different types of Google Analytics trackings installed on a website like:

• Event Tracking
• Cross-domain tracking
• Social Interactions tracking
• User ID
• Custom dimensions
• Custom metrics
• and many more

Through my tag auditing system, you can:

1. Identify the pages where GA/GTM tags are found.
2. Identify the pages where GA/GTM tags are not found.
3. Identify the pages where data layers are found or not found.
4. Identify any tag whether it was fired or not.
5. Identify old GA configurations, the ones based on Classic GA traditional syntax or even older urchin syntax.
6. Identify non-Google tags and their location.
7. Identify any type of GA tracking
8. Scan any number and type of tags and technologies used on a website.

Custom Google Analytics Tag Auditing System

Let us suppose you want to audit your website for following tags and technologies:

1. Universal Analytics Tracking Code
2. Classic Google Analytics Configuration
3. Universal Analytics Cross-domain Auto linking
4. Universal Analytics event tracking
5. Facebook Custom Audience

You want to scan your website to find the pages which contain or do not contain these tags.

To do this follow the steps below:

Step-1: Open Screaming Frog SEO Spider tool and then go to Configuration > Spider:

Step-2: Uncheck following checkboxes to speed up your crawl:

1. Check images
2. Check CSS
3. Check JavaScript
4. Check SWF
5. Check External Links

By unchecking these checkboxes you will greatly reduce the crawling time esp. if your website has got hundred thousands web pages.

Step-3: Go to Configuration menu and click on ‘Custom’:

Step-4: Set up following Custom Filters:

Note: The search strings (like analytis.js) that I have selected to find particular tags are based on the special characters which Screaming Frog SEO Spider can detect.

I am using the latest version of this crawler which is 3.3 and this version supports following special characters:

1. = (equals to)
2. / (slash)
3. . (dot)
4. – (dash)
5. : (colon)
6. ‘ (single quotation mark)

Screaming frog is not able to detect strings which contain any of the following special characters:

1. _ (underscore)
2. ( (parentheses)
3. [ (bracket)
4. ? (question mark)

Step-4: Now start the crawl and once the crawl is finished, click on the Custom tab on the right hand side:

Under the ‘Filter’ drop-down menu, you can see all the filters you set up before starting the crawl.

Select one of the filters from the drop-down menu.

You can now filter out all those web pages which contain or do not contain your specified tags.

You can then download the list into excel by clicking on the ‘Export’ button and then update/remove the tag code from a page. 

Following is the list of tags along with their search string for easy reference:

Classic Google Analytics Tags

	Tag	Search String
1	GA traditional Tracking Code	getTracker
2	GA asynchronous Tracking Code	ga.js
3	Classic GA configurations	gaq.push
4	Custom Variables	setCustomVar
5	Traditional GA configuration	pageTracker
6	Classic GA Ecommerce Tracking	addTrans
7	GA Local currency setup	currencyCode
8	GA Event Tracking	trackEvent
9	Google Analytics Content Experiments	//www.google-analytics.com/cx/api.js
10	GA Cross domain tracking – Traditional	pageTracker._setDomainName (won’t work in screaming frog)
11	GA Cross domain tracking – Asynchronous	setDomainName
12	GA Search Engine Configuration	addOrganic
13	GA Session Timeout Configuration	setSessionCookieTimeout
14	GA Campaigns Timeout Configuration	setCampaignCookieTimeout
15	GA Referral exclusion Configuration	addIgnoredRef
16	GA Search Terms exclusion Configuration	addIgnoredOrganic
17	GA Social Interactions Tracking	trackSocial
18	GA User Timings	trackTiming
19	GA Enhanced link attribution	pluginUrl
20	GA Content Group	setPageGroup
21	Obsolete Google Analytics	urchin.js

Universal Analytics Tags

	Tag	Search String
1	Universal Analytics Tracking Code	analytics.js
2	UA Cookie Name Customization	cookieDomain
3	UA Enhanced Link Attribution	linkid.js
4	UA App / Screen Tracking	screenview ‘appName’:
5	UA Cross Domain Tracking	linkerParam
6	UA Cross Domain Auto Linking	‘require’, ‘linker’
7	Client ID	clientId
8	Custom dimensions	‘dimension1′
9	Custom metric	‘metric1’
10	UA Advertising/Display Features	‘require’, ‘displayfeatures’
11	Multiple Trackers	.send’, ‘pageview’
12	UA Ecommerce Tracking	‘require’, ‘ecommerce’
13	Enhanced Ecommerce Tracking	‘require’, ‘ec’
14	UA Event Tracking	‘send’, ‘event’
15	Exceptions Tracking	‘send’, ‘exception’
16	UA Plugins	‘require’,
17	UA Social Interactions	‘send’, ‘social’
18	User ID	‘userId’:
19	UA User Timings	‘send’, ‘timing’
20	UA Content Group	‘set’, ‘contentGroup

Other Marketing Tags

	Tag	Search String
1	Google Adwords Remarketing	var google_remarketing_only = true (won’t work in screaming frog)
2	Google Adwords Conversion Tracking	var google_remarketing_only = false (won’t work in screaming frog)
3	Crazy Egg	script.crazyegg.com
4	Kissmetrics	//i.kissmetrics.com/i.js
5	Inspectlet	//cdn.inspectlet.com/inspectlet.js
6	Facebook Conversion Tracking	Facebook Conversion Code
7	Facebook Custom Audience	‘addPixelId’
8	Mix Panel	cdn.mxpnl.com
9	Optimizely	cdn.optimizely.com
10	Google Tag Manager	gtm.js
11	GTM Data Layer	dataLayer.push var dataLayer
12	Adobe Site Catalyst	assets.adobedtm
13	AdRoll	adroll.com

Other article you will find useful: Cross domain tracking in Google Tag Manager