Google's Privacy & Messaging Tool: How to find the TC String

Here's how to find the TC String on any site that uses Google's Privacy & Messaging Tool, the Consent Management Platform (CMP) built into Google AdSense, Ad Manager and AdMob.

What is the TC String?

The TC String (also known as TCF String, Transparency and Consent Framework String, or IAB TCF 2.2 Consent String) is an encoded string that contains the consent choices that the user has made in a Consent Management Platform, or CMP.

This string is passed to Google and other advertising vendors so the correct ads can be served. For example, if a user doesn't consent to personalized ads, this choice is encoded in the TC String and the user won't be served any personalized ads.

Here, we're talking specifically about finding the TC String generated by Google's Privacy & Messaging Tool, the optional CMP built into Google AdSense, Google Ad Manager and Google AdMob. You may also see the tool referred to as 'Google's IAB GDPR Message' or 'Funding Choices' (the name of a previous iteration).

The Privacy & Messaging Tool in Google Ad Manager

Finding the TC String

You can find the TC String at any time after the Privacy & Messaging Tool consent form has been completed. Here's how:

1. In Chrome, open Dev Tools (hit F12 or go to Menu > More tools > Developer tools)
2. Open the Network tab
3. Refresh the page and wait for it to finish loading
4. In the Filter box, type in 'ads?'

5. Click on the (first) network request beginning with 'ads?'
6. In the panel on the right, open the Payload tab

7. You'll find your TCF String listed under the parameter 'gdpr_content'

It will look something like this:

CP7aT0AP7aT0AEsACBENArEoAP_gAEPgAAwIINJD7D7FbSFCwHpzaLsAMAhHRsCAQoQAAASBAmABQAKQIAQCgkAQFASgBAACAAAAICZBIQAECAAACUAAQAAAAAAEAAAAAAAIIAAAgAEAAAAIAAACAAAAEAAIAAAAEAAAmAgAAIIACAAAhAAAAAAAAAAAAAAAAgAAAAAAAAAAAAAAAAAAAQOhQD2F2K2kKFkPCmQWYAQBCijYEAhQAAAAkCBIAAgAUgQAgFIIAgAIFAAAAAAAAAQEgCQAAQABAAAIACgAAAAAAIAAAAAAAQQAAAAAIAAAAAAAAEAAAAAAAQAAAAIAABEhCAAQQAEAAAAAAAQAAAAAAAAAAABAAA

A TC String doesn't have a fixed number of characters - its length is determined by the number of consent choices that it contains. However one giveaway is that it often contains groups of four or more As together (AAAA).

Decoding the TC String

Once you have the TC String that was generated by the Privacy & Messaging Tool, you can run it through UniConsent's TCF Consent String Decoder. This will show you all the information that the TC String contains:

• The purposes that you have consented to
• The advertising vendors that have 'legitimate interest' (ie that are using your personal data on the basis of their own legitimate interest rather than your consent)

For example, looking at the TC String above, I can see I consented to the following TCF 'Purposes':

This could be useful for troubleshooting the Privacy & Messaging Tool and making sure the consent string it generates contains the consent choices you expect.