TCF v2.3: February 2026 Deadline -- Are You Ready?

What TCF v2.3 Requires

IAB Europe published version 2.3 of the Transparency and Consent Framework with a major requirement: the addition of a “disclosedVendors” segment in the consent string (TC string). This segment explicitly lists the advertising vendors the user has been informed about via the CMP.

The compliance deadline was set for February 2026. TC strings that do not contain this segment are now considered invalid by compatible programmatic platforms.

Consequences of a Non-Compliant TC String

When a TC string is deemed invalid, demand-side platforms and SSPs apply a default mode: “Limited Ads.” This mode drastically restricts eligible bids. Personalized ads are excluded, bids are lower, and a significant share of demand disappears.

Industry estimates suggest a potential programmatic ad revenue drop exceeding 50% for publishers whose TC strings are not compliant. The mechanism is binary: either the string is valid and full bidding is accessible, or it is not and revenue drops.

Who Is Affected?

All publishers and websites monetizing their audience through programmatic advertising in Europe are directly affected. Advertisers buying programmatically are indirectly affected: if publishers do not transmit valid TC strings, the volume of addressable inventory shrinks.

Sites using an IAB-certified CMP but that have not updated to a v2.3-compatible version are most at risk. The CMP may be in place and functionally visible while generating outdated strings in the background.

What to Verify

The first step is to confirm the TCF version supported by your CMP. Contact your provider (Didomi, OneTrust, Cookiebot, Quantcast, Sourcepoint) and verify that the latest SDK update generates v2.3 TC strings with the disclosedVendors segment.

Then test the generated string. The IAB TCF Decoder tool lets you decompress a TC string and verify the segment’s presence. You can also use the Chrome console to intercept the value of the euconsent-v2 cookie and analyze it.

Also verify the list of vendors declared in your CMP. The disclosedVendors segment must exactly match the vendors displayed to the user. A discrepancy between the displayed list and the encoded list invalidates the string.

Act Now

If your CMP is not yet updated, compliance is urgent. Each day of delay represents a direct revenue loss for publishers. For advertisers, a rigorous CMP configuration ensures that your publisher partners can properly monetize the audience you target.

The technical update is generally quick: update the CMP SDK and verify configuration parameters. The longest part is often the internal alignment between legal, product, and technical teams.