Glossary/Privacy and identity/IAB TCF
What is the IAB TCF (Transparency and Consent Framework)?
How the IAB Transparency and Consent Framework works, what the TC string carries, what changed in TCF 2.2, and what it means for publishers who sell audiences.
Written by Samhub with the help of AI·Updated 13 Oct 2026·4 min readThe IAB TCF (Transparency and Consent Framework) is a standard from IAB Europe for collecting readers’ consent and passing it on to ad tech vendors in a format they all understand.
How the TCF works
The reader sees a consent banner
A registered consent management platform (CMP) shows the purposes and the vendors that want to use the data.
The choices are stored as a TC string
The answers are encoded in a short text string, the Transparency and Consent string.
Each vendor checks its permission
Vendors may only process data for the purposes the reader agreed to.
Key parts of the framework
| Part | What it is |
|---|---|
| Purposes | Standard reasons for using data, such as measuring ads or building a profile for personalized ads. |
| Global Vendor List | The register of ad tech vendors that take part, each with its declared purposes. |
| CMP | The consent tool on the site. It must be registered with IAB Europe. |
| TC string | The encoded record of the reader’s choices, passed along the ad chain. |
What changed in TCF 2.2
Version 2.2 made consent clearer for readers. Vendors can no longer use legitimate interest as the legal basis for personalized advertising and content, and the CMP has to show more about each vendor, including how many vendors are asking.
16 pages for publishers, with a checklist for data, programmatic and direct sales.
What the TCF means for publishers
Your consent rate decides how much of your audience you can use for targeted advertising. A clear, honest banner and a good reader relationship raise consent. Logged-in readers and first-party data then make the consented audience worth more to buyers.
Addressability at Stampen Media after moving its reader data into one layer with Samhub.
Frequently asked questions
A short encoded string that records which purposes and vendors a reader has agreed to. It is passed to every vendor in the ad chain.
TCF 2.2 removed legitimate interest as a basis for personalized ads and content, and requires more information about vendors in the consent banner.
Yes. The banner must come from a CMP that is registered with IAB Europe.
Related terms
Collects and stores readers’ consent choices.
Any information that relates to an identifiable person.
The share of your audience you can recognize and target.
Data you collect directly from your own readers.
Collecting data through your own server instead of the browser.
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