Conversion linker

Conversion linker tags are used to help tags measure click data so that conversions are measured effectively. Deploy a conversion linker tag on any page where visitors may land after they click an ad or promotion.

When people click on your ads, the URL of the conversion page on your website typically includes information about the click. When a site visitor takes an action that you’ve tagged as a conversion (e.g. when a Google Ads conversion tracking tag is fired), the click information is used to associate that conversion with the click that brought the visitors to your site.

The conversion linker tag automatically detects the ad click information in your conversion page URLs, and stores this information in first-party cookies on your domain for web pages, and passes the data in URLs for AMP pages. If you use a conversion linker tag with Google Marketing Platform products, the conversion linker tag may also store unique identifiers in those cookies.

Basic setup

To set up a conversion linker tag:

  1. Click Tags and then New.
  2. Click Tag Configuration and select Conversion Linker.
  3. Select a trigger. In most cases, you should use a trigger that fires on all page views, or on specific page views where site visitors will land after an ad is clicked.
  4. Save and publish your tag configuration.

Instances of conversion linker tags for web containers will have these additional options to link across domains and to override cookie settings. (Conversion linker tags for AMP containers have no additional configuration options.)

Link across domains

Conversion linker tags in web containers can be configured to link across domains for cases where you have the landing pages and conversion pages on multiple domains. When you select this option, hyperlinks that point to a linked domain will have a linker parameter appended to the URL. A destination domain with a compatible linker tag will check inbound URLs for linker parameters. If a valid linker parameter is found, a 1st party measurement cookie is extracted and stored. Learn more.

To configure the conversion linker tag to work with multiple domains:

  1. Select Enable linking across domains. This setting will enable this tag to handle incoming links that have a linker parameter.
  2. Optional, but recommended: In Auto Link Domains, enter a list of domains that should be linked with this tag. Any links that point to a domain listed in this field will have a linker parameter appended to the URL.
  3. Optional: To link forms, set Decorate Forms to true.
  4. Optional: If you need to tell Tag Manager to read the unique parameter from a fragment delimiter (#) instead of a standard query delimiter (?), set URL Position to Fragment. Otherwise, leave this option set to the default Query Parameter option.
Note: Decorate Forms will only work in conjunction with the URL Position option set to Query Parameter. This is because some browsers strip off the URL fragment from form submissions.

Override cookie settings (advanced)

For most cases, the basic configuration of this tag will be sufficient. Only adjust the settings if you have a specific need that requires it.

You may need to override some cookie settings in cases where you already have cookies with the same names, you need to have multiple sets of cookies, or when you don’t want ad click info from one subdomain of your website to be available for conversions on another subdomain. For these cases, use the override cookie settings feature.

The conversion linker tag sets ad click information in cookies named _gcl_aw and _gcl_dc, and uses the top-most domain and root level path. If you need to override any of these settings, you can do so in Linker Options.

When you select the Override cookie settings checkbox, text fields for Name prefix, Domain, and Path will appear:

  • Name: This is the prefix used as part of the cookie names.The default prefix name is _gcl. For example, if you change the Name field to _gcl2, the Conversion Linker tag will set cookies named _gcl2_aw and _gcl2_dc. If you change the prefix of the cookie names, any tags that read ad click info from these cookies (e.g. Google Ads conversion tags) must also be configured to use the same prefix.
  • Domain: This is the domain of your website on which the first-party cookies should be set. By default, a conversion linker tag will use the highest level domain on which it can set cookies. For example, if your website address is blog.example.com, a conversion linker tag will set the cookie domain to example.com. Only set this field if you need to limit the cookies to a lower-level domain.
  • Path: This is the path used to set the cookies. By default, the cookie path will be the root level of the domain. Only set this field if you need to limit the cookies to a subdirectory of a domain.

You can also edit how tags work with first-party cookies set by conversion linker tags: These tags will offer two additional configuration options in the Conversion Linking section:

  • Enable Conversion Linking: By default, all tags that read data set by the conversion linker tag have "Enable Conversion Linking" set to true. Set this value to false if you need to disable the tag's ability to work with Conversion Linker tags.
  • Cookie Prefix: If you have changed the cookie name prefix in a conversion linker tag, add that same prefix in this field so that the tag can read data from the correct cookie.
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