Set up Google tag gateway for advertisers

This document is for users who want to deploy the Google tag gateway for advertisers. We recommend Google tag gateway for advertisers for the most durable tag configuration.

Overview

Google tag gateway for advertisers lets you deploy a Google tag using your own first-party infrastructure, hosted on your website's domain. This infrastructure sits between your website and Google's services. The setup in this documentation will help you better measure your website. You can set it up using your existing Content Delivery Network (CDN), load balancer, or web server.

In standard Google tag setups, your web page requests a Google tag from a Google domain. When the tag fires, it sends measurement requests directly to the Google product. With Google tag gateway for advertisers, your website loads the Google tag from your first-party domain. When the tag fires, some measurement requests will be sent to Google using your first-party domain.

This diagram represents the information flow in Google tag gateway for advertisers:

Before you begin

This guide assumes that your website is already configured with:

• A Google tag or Tag Manager container
• A content delivery network (CDN) or load balancer that can forward requests to external endpoints

To get started, pick your setup type.

Manual setup Automated setup with Cloudflare

1. Choose the tag serving path

You must reserve a path on your website domain for serving the tag. Make sure this path is not already in use on your domain.

To set up Google tag gateway for advertisers, choose any path that isn't already in use on your site. To reduce the likelihood of conflicting with a path already on the site, you could choose any combination of letters and numbers, or if you want a more readable path, you could choose to use a word such as /metrics, /securemetric, /analytics, or any other word you want.

The path must not be the root path / or exceed 100 characters.

Fill in the following to populate the examples throughout this document.

Your domain: example.com
Google tag ID: G-12345
Tag serving path: /metrics

Caution: This setup reroutes all traffic with the chosen path. To avoid affecting your website, choose a path that's not already in use.

2. Route traffic

This section assumes that your website is already using a CDN or load balancer that supports routing traffic by paths.

Google Cloud

You need to set up a new backend that looks up the approximate geographic location of the site visitor and create routing rules in your existing External Application Load Balancer.

Create the new backend

1. Open GCP load balancer

2. In your load balancer, open the Backend configuration section. Create a new backend service.

3. Configure your new backend service with geolocation information:

   • Specify a name, such as measurement-be-svc.
   • Set Backend type to Internet network endpoint group.
   • Set Protocol to HTTPS and leave Timeout as the prefilled value.
   • Under Backends, click the Internet network endpoint group drop-down and create a new internet network endpoint group:
     • Set Network endpoint group type to Internet NEG (Global, Regional).
     • Set Scope to Global.
     • Set Add through to Fully qualified domain name and port.
     • Set Fully qualified domain name to G-12345.fps.goog.
     • Click CREATE to create the endpoint.
     • Close the Network endpoint group tab to return to the New backend service tab.
   • Search the name of the new network endpoint group and select it.
   • Open the Advanced configurations section. Add the following custom request headers.

     Header name	Header Value
     Host	G-12345.fps.goog
     X-Forwarded-Country	{client_region}
     X-Forwarded-Region	{client_region_subdivision}

   • Review the other settings. Neither Cloud CDN nor Cloud Armor are required for this integration, so you may safely disable both.
   • Save the new backend service.

Configure routing rules

1. In your load balancer, open the Routing rules section.

2. Add the following host and path rules:

   Host	Path	Backend
   *	/metrics/*	measurement-be-svc

3. Update the load balancer configuration.

4. In a browser, verify the set up by navigating to: https://example.com/metrics/healthy. The page should have the text ok. Verify that geographical information is being included by navigating to: https://example.com/metrics/?validate_geo=healthy. The page should have the text ok.

Cloudflare

To serve your tag in Google tag gateway for advertisers, you will create a CNAME entry for a new subdomain, create an Origin Rule to forward requests, and create a Transform Rule to include geolocation information. To complete this setup, you will need to have a Cloudflare Enterprise plan. If you don't have an Enterprise plan, consider using the Cloudflare automated setup instead.

Create CNAME entry

Note: Tags won't use this CNAME entry; Cloudflare uses it to route requests internally.

Choose a subdomain to reserve for the CNAME entry. Fill in the following to populate the examples throughout this document. This CNAME is never exposed outside your Cloudflare configuration, so the name is arbitrary.

CNAME subdomain: fps

1. In the DNS tab, open the Records section.
2. Add a new record with the following configuration:
   • Set Type to CNAME.
   • Set Name to fps.
   • Set Target to G-12345.fps.goog.
3. Save the CNAME record.

Create the Origin Rule

1. In the Rules tab, open Origin Rules and create rule.
2. Enter a rule name, such as Route measurement.
3. Match incoming requests based on a Custom filter expression and click Edit expression.
4. Paste the following expression in the builder: (http.host eq "example.com" and starts_with(http.request.uri.path, "/metrics"))
5. Update the Host Header to Rewrite to... G-12345.fps.goog.
6. Update the DNS Record to Override to... fps.example.com.
7. Save the Origin Rule.
8. If there are other Origin Rules, increase the newly created Rule's position so that it will run after any other wildcard paths.
9. In a browser, verify the setup by navigating to: https://example.com/metrics/healthy. The page should read ok.

Include geolocation information

1. In the Rules tab, open Settings
2. Enable the Add visitor location headers option.
3. Wait a few minutes for the rule to propagate. In a browser, verify the set up by navigating to: https://example.com/metrics/?validate_geo=healthy. The page should read ok.

Other

To serve your tag in Google tag gateway for advertisers, you need to configure your CDN or load balancer to route requests to the Google tag gateway for advertisers endpoint.

1. Add an origin or backend that points to G-12345.fps.goog.
2. Override the Host header to be equal to G-12345.fps.goog. Allow all cookies and query strings to be forwarded.
3. Pass the visitor's geolocation information by including either of the following headers:
   • X-Forwarded-CountryRegion - The user's country and region in a single ISO 3166-2 code (for example: US-CA).
   • X-Forwarded-Country and X-Forwarded-Region:
     • X-Forwarded-Country - The users's country as an ISO 3166-1 alpha-2 code (for example: US).
     • (Optional) X-Forwarded-Region - The user's region subdivision code (for example: CA).
   • If both sets of headers are included, X-Forwarded-CountryRegion will be used.
4. Add a path rule for /metrics/* to route traffic to first-party mode.
5. Configure the reserved path to have higher priority than the default
6. Add a path rule for /metrics/* to route traffic to Google tag gateway for advertisers.
7. Configure the reserved path to have higher priority than the default rule.
8. In a browser, verify the set up by navigating to: https://example.com/metrics/healthy. The page should read ok.

Step 3: Update the scripts on the website to use the Measurement Path

Replace the scripts on each page of the website with one of the following:

gtag.js

At the top of the <head> section, find the two lines of script with your Google tag ID:

<!-- Google tag (gtag.js) -->
<script async src="https://www.googletagmanager.com/gtag/js?id=G-12345"></script>

and replace them with the measurement path instead:

<!-- Google tag (gtag.js) -->
<script async src="/metrics/"></script>

gtm.js

At the top of the <head> section, replace the Tag Manager snippet with the following:

<!-- Google Tag Manager -->
<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
'/metrics/?id='+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','');</script>
<!-- End Google Tag Manager -->

Test the measurement set up

To test the measurement set up, configure your container to have at least one tag that fires.

1. Go to Tag Assistant and preview your container. Navigate through your site to trigger events.

2. In the Summary > Output > Hits Sent tab, verify that the hits are routed to /metrics.