Conversion Linker in Google Tag Manager: A Practical Guide for Affiliate Marketers

Advertising, targeting, and measuring campaign performance have traditionally relied heavily on third-party cookies. As privacy concerns have grown, many browsers have introduced stricter controls on both first-party and third-party cookies, which play an important role in Google Ads conversion tracking.

Conversion Linker is a preconfigured tag in Google Tag Manager that captures ad click parameters, such as the Google Click ID, from landing page URLs and stores them in first-party cookies on your domain. This helps Google Ads measure conversions when browser privacy features block third-party tracking.

Google Chrome began introducing restrictions on third-party cookies on January 4, 2023. Safari has blocked them for some time, and its Intelligent Tracking Prevention (ITP) has also tightened restrictions on first-party cookies in recent years.

How can you keep track of what your ads actually deliver? There is no perfect solution, but storing Google Ads click data in a first-party cookie helps attribute conversions correctly. Safari still imposes limits, but having some click data is better than having none.

Newer tools, such as enhanced conversions, can send hashed email addresses and similar data to Google. Combining cookies with hashed data can improve measurement further.

This article covers two ways to create first-party cookies for conversion tracking, including the Conversion Linker tag in Google Tag Manager.

Table of Contents

Here is what the article covers:

• Why is this a problem?
• What are the possible solutions?
• Conversion Linker in Google Tag Manager
• How to set up a Conversion Linker tag
• Conversion Linker for server-side tracking
• Optional configuration
• Enable linking on all page URLs
• Enable linking across domains
• Override cookie settings
• What comes next?
• Final thoughts

Why Is This a Problem?

Running ads without measuring their effectiveness is like heading out to sea without a compass. You are moving, but you cannot tell whether you are going in the right direction.

Google Ads uses third-party cookies to support targeting based on content users have viewed and to track what happens after someone interacts with an ad. That might be a product view, a purchase, or an email signup. As these cookies become less available, this tracking becomes harder.

In Google Ads, you can define conversions: actions that matter to your business and happen after someone interacts with an ad. Tracking them shows which ads generate valuable activity and helps you decide where to allocate your budget.

As third-party cookies are phased out, more of that measurement depends on first-party cookies.

Why focus on first-party cookies? Browsers such as Safari, with its Intelligent Tracking Prevention, primarily block or restrict third-party cookies. These are cookies set by a domain other than the one a user is visiting, such as an ad network setting a cookie on a publisher’s website.

First-party cookies are set by the domain the user is visiting. Browsers generally treat them less strictly, although some, including Safari, also limit their lifespan.

Conversion Linker uses this difference. It takes ad click information that previously depended on third-party tracking and stores it in a first-party cookie on your own domain. This makes the data somewhat more resilient to browser privacy restrictions.

First-party cookies face restrictions too. For now, though, they remain important for preserving Google Ads click data and tracking conversions.

What Are the Possible Solutions?

To keep conversion tracking working, you need a tag across your website that creates a first-party cookie on your domain. This cookie stores an identifier for the visitor or the ad click that brought them to your site.

There are two ways to do this:

1. Install the Google tag for Google Ads conversion tracking.

If you are not using Google Tag Manager, you can install the Google tag directly.

If a Google tag already runs on every page, you can modify its existing code to send data to your Google Ads account. Replace TAG_ID on the highlighted line with the ID provided when you configure your conversion tracking tags.

The Google tag supports several Google products, including Google Analytics 4. When you create a website conversion action in Google Ads, you are prompted to install it on every page of your website. You also need an event snippet or a phone snippet to track the relevant conversions.

2. Create a Conversion Linker tag in Google Tag Manager.

If your tracking runs through GTM, you can use its preconfigured Conversion Linker tag to store ad click information in a first-party cookie. The rest of this guide focuses on that method.

Note: Google Analytics 4 no longer preserves the GCLID in a cookie for Google Ads conversion tracking events. Linking your Google Analytics and Google Ads accounts alone is no longer sufficient, so you need one of the methods above.

If you need a quick overview, the flowchart below shows whether your web tracking setup needs Conversion Linker. Start with the blue diamond.

Conversion Linker in Google Tag Manager

When someone clicks your ad, the landing page URL contains a Google Click ID, or GCLID. Previously, the browser could store this information in a third-party Google Ads cookie.

When that visitor completes an action you have defined as a conversion, the Google Ads conversion tracking tag fires. The conversion is then associated with the original ad click.

Restrictions on third-party cookies make this process less reliable. You can no longer depend on a third-party Google Ads cookie to preserve the click information.

If you use Google Tag Manager, Conversion Linker addresses this by storing ad click information in a first-party cookie on your domain. Google Ads can then use that information to measure conversions after someone clicks an ad and visits your site.

Update: Google currently recommends implementing the main Google tag with your Google Ads ID, such as AW-XXXXXX, and making sure it fires early on every page. One option is the “Initialization - All Pages” trigger.

The Google tag now includes functionality previously handled by Conversion Linker: detecting gclid and setting first-party cookies.

Do you still need a separate Conversion Linker tag?

• If you have implemented the Google tag with your AW- ID: A separate Conversion Linker tag may be redundant because the Google tag already handles its function. GTM often will not prompt you to add it when the Google tag is present. Keeping both is also safe. A standalone Conversion Linker tag firing on “All Pages” or “Initialization” alongside the Google tag has no known conflicts or duplication issues. It provides an additional check that click information is being stored.
• If you have not implemented the Google tag with your AW- ID: For example, if you still use older Ads tags, the standalone Conversion Linker tag remains essential.

How to Set Up a Conversion Linker Tag in Google Tag Manager

When Google Consent Mode v2 is implemented, Conversion Linker automatically respects the visitor’s ad_storage consent state.

If ad_storage is denied, Conversion Linker does not read or write the first-party _gcl_aw cookie. Instead, ad click information is passed through functional URL parameters in cookieless pings sent to Google.

If ad_storage changes to granted during the same session, Conversion Linker writes the first-party cookie, provided the ad click parameters are still available in the URL.

The setup itself is straightforward. In GTM, open Tags in the left-hand navigation and click New.

Choose Conversion Linker as the tag type.

Set the trigger to All Pages.

Name and save the tag. Check that it works in Preview and DebugView, then save and publish the container.

That is the basic setup.

Note: Configure Google Consent Mode if you use Google Ads in the European Economic Area (EEA).

How Conversion Linker Interacts with Consent Mode v2

With Google Consent Mode v2 in place, Conversion Linker follows the ad_storage consent parameter:

• When ad_storage is denied: Conversion Linker does not read or write first-party advertising cookies, such as _gcl_aw or _gcl_dc. Ad click information, including gclid, is passed through functional URL parameters in pings sent to Google Ads without being stored in those cookies.
• When ad_storage is granted: Conversion Linker reads the ad click parameter from the URL and writes the first-party _gcl_aw cookie on your domain.

If a visitor changes their choice from denied to granted during the session, Conversion Linker can pick up the gclid parameter and set the cookie without requiring another ad click. The parameter must still be in the address bar or have been preserved through URL linking.

Conversion Linker for Server-Side Tracking

If you use server-side tracking, follow the same steps in your server-side container to create a Conversion Linker tag.

The main advantage is how the cookies are written. Browser JavaScript is heavily restricted by Safari’s Intelligent Tracking Prevention. A server-side Conversion Linker instead sets _gcl_aw and _gcl_dc cookies through HTTP response headers using Set-Cookie.

When those headers come from a custom subdomain of your website, browsers treat the cookies as first-party cookies. This can extend the lifespan of Google Ads click data beyond the seven-day or 24-hour limits Safari applies to cookies created through JavaScript.

For this setup to work, your server-side container must use a custom subdomain of your main website. If you use the default cloud app address supplied by your hosting platform, the cookies will be treated as third-party cookies and blocked.

If you move Ads conversion tracking to this setup, remove equivalent Ads conversion tracking tags from the web container to avoid duplicate data.

Optional Configuration in Conversion Linker

For many setups, Conversion Linker does not need any further configuration.

Enable Linking on All Page URLs

By default, Conversion Linker reads gclid or dclid from the initial landing page URL and stores it in a cookie. If a visitor moves to another page before the cookie is set, perhaps because they have not granted consent yet, the parameter may disappear from the URL.

Enabling this option changes that behavior. Conversion Linker adds the gclid or dclid parameter to link and form URLs on the page, allowing the click identifier to stay in the URL as the visitor navigates through your site.

This can help when a cookie consent banner delays storage:

• A visitor clicks an ad and lands on Page A with gclid=xyz in the URL.
• They interact with the consent banner but have not accepted yet.
• They follow an internal link to Page B. With URL linking enabled, Page B also receives gclid=xyz.
• On Page B, they grant consent.
• Conversion Linker can now read gclid from Page B’s URL and write the _gcl_aw cookie, even though it could not do so on the initial landing page.

Use this setting carefully. Adding parameters can break some links or page functionality.

Enable Linking Across Domains

If your website spans several domains, consider enabling cross-domain linking. This is useful when the landing page and conversion page are on different domains.

Conversion Linker adds a parameter to links and forms that take visitors from one domain to another. This allows the Google Click ID stored in the cookie to carry through the journey.

After selecting Enable linking across domains, enter all domains involved in that journey. Separate each domain with a comma.

Override Cookie Settings (Advanced)

You may need to override the default cookie settings when:

• Cookies named _gcl_aw and _gcl_dc already exist.
• You need several sets of cookies.
• You want to prevent ad click information from one subdomain being used for conversions on another.

Most setups do not need these changes. That is why the option is marked “Advanced.”

Selecting Override cookie settings gives you three fields: name, domain, and path.

• Name controls the cookie name prefix. The default is _gcl. If you change it to _gcl2, cookies created by Conversion Linker use the new prefix, such as _gcl2_aw and _gcl2_dw. Note: If you change the prefix, configure the tags that use these cookies, including Google Ads conversion tags, to use the updated prefix.
• Domain controls where the first-party cookie is set. By default, Conversion Linker sets cookies on the highest-level domain. For a website on a shop subdomain, this means the cookie is set on the main domain. Change this field only if you need to restrict the cookie to a lower-level domain, such as the shop subdomain.
• Path controls the cookie’s path. The default is the root path, /. Change it only if you need to limit the cookie to a specific subdirectory, such as /clothing.

Troubleshooting: Why Is the _gcl_aw Cookie Missing?

If you clicked an ad containing a gclid parameter but cannot find the _gcl_aw cookie in your browser’s developer tools, check these three common issues:

1. Redirects remove query parameters. If the landing page automatically redirects to another version of your domain, such as the version with www, the server may drop gclid before Google Tag Manager loads. Test the landing page and check whether gclid remains in the address bar after loading finishes.
2. The consent banner blocks the tag on the initial page load. If the banner blocks GTM or delays tags until the visitor clicks “Accept,” Conversion Linker will not fire on the initial page view. Enabling Enable linking on all page URLs helps preserve gclid in internal links, so the cookie can be written on a later page view after consent is granted.
3. The container trigger fires too late. If Conversion Linker fires on DOM Ready, Window Loaded, or another later event instead of “Initialization - All Pages” or “Consent Initialization - All Pages,” other tags may run before the cookie exists. Fire Conversion Linker at the earliest possible trigger stage.

What Comes Next?

Conversion Linker helps preserve cookie-based attribution, but Google’s longer-term strategy increasingly includes enhanced conversions.

This feature sends hashed first-party customer data, such as email addresses or phone numbers, from your website alongside conversion data. Google can match it against signed-in Google accounts that interacted with your ads, supporting attribution when cookies are unavailable.

Once your basic tracking works reliably with Conversion Linker or the Google tag, enhanced conversions are the recommended next step. Combining both methods provides more robust Google Ads conversion measurement.

You can also add server-side GTM, including approaches such as custom loaders or a same-origin setup.

Conversion Linker in GTM: Final Thoughts

First-party cookies help improve the accuracy of Google Ads conversion tracking. They face growing restrictions too, but preserving some click information is still better than losing it entirely.

Conversion Linker is a preconfigured tag in Google Tag Manager. It captures ad click parameters, such as gclid and dclid, from landing page URLs and stores them in first-party cookies on your website’s domain.

If your Google Ads tracking runs through GTM, adding Conversion Linker supports conversion measurement in both web and server-side setups.

Alternatively, you can install a new Google tag or modify an existing one for Google Ads conversion tracking.

Linking Google Analytics and Google Ads alone is no longer sufficient. You need one of these two methods.

Browser technology keeps changing, but ads can still drive valuable activity to your website. The tracking setup needs to keep pace.

Google is also investing in enhanced conversions, which send hashed user data, such as an email address or first name, alongside conversion information. This provides another way to support measurement as cookie availability changes.

Our Telegram Channel - @SpyLeader

For Spy Service please write - @TrafficSponsor