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Category: TCF and Vendors

Special Features

Also known as: TCF Special Features
Simply put

Special Features are a defined category within the IAB Europe Transparency & Consent Framework (TCF), a standardized system used by websites and advertising vendors to signal how personal data may be used. Unlike ordinary purposes that a user might allow through a general consent choice, Special Features cover certain sensitive data-processing activities that always require the user's explicit, separate opt-in and cannot rely on legitimate interest. Because the specific list and definitions of Special Features are set by IAB Europe's TCF policies, the authoritative meaning should be confirmed against the current TCF policy documents rather than a general dictionary sense of the words.

Formal definition

Within the IAB Europe TCF, 'Special Features' are a distinct classification of data-processing activities that, per TCF Policies, may only be based on user consent (explicit opt-in) and are not permitted to be transacted on a legitimate-interest legal basis. This distinguishes them from ordinary TCF 'Features,' which do not carry their own independent legal basis and instead piggy-back on the legal basis chosen for an associated Purpose. The precise enumerated Special Features, their scope, and the signalling requirements are established and periodically revised by IAB Europe through the TCF specification and accompanying policy documents; practitioners should treat the current version of those documents as the controlling reference. Note that the TCF is an industry self-regulatory standard intended to support GDPR and ePrivacy compliance; adherence to its Special Feature signalling does not by itself guarantee compliance with applicable law, and TCF definitions are specific to the EU/EEA context and may not map onto other jurisdictions' frameworks. This entry describes the term as used in the TCF only; the exact current list of Special Features is out of scope and should be verified against the published TCF policies.

Why it matters

Special Features sit at the point where the IAB Europe TCF's signalling logic meets some of the more sensitive data-processing activities in online advertising. Because Special Features may only be transacted on the basis of the user's explicit opt-in and cannot rely on legitimate interest, they carry a stricter consent requirement than many ordinary TCF Purposes. Getting this distinction wrong, for example by attempting to process a Special Feature without a valid consent signal, can undermine the legal footing of an entire advertising transaction and expose publishers and vendors to compliance risk under the GDPR and applicable ePrivacy rules in the EU/EEA.

Who it's relevant to

Privacy and data protection officers
DPOs and privacy leads need to understand that Special Features require a separate explicit opt-in and cannot rely on legitimate interest, so a general consent choice does not cover them. They should verify how their organisation's CMP handles Special Feature signals and confirm the current list against published TCF policies, recognising that TCF adherence supports but does not guarantee GDPR or ePrivacy compliance.
AdTech vendors and publishers
Vendors and publishers participating in the TCF must read Special Feature opt-in signals correctly and avoid transacting these activities on a legitimate-interest basis. Because these are among the more sensitive processing activities in the framework, mishandling the associated signals can undermine the legal footing of a transaction.
CMP implementers and web developers
Those configuring or building consent management platforms should ensure that Special Features are surfaced to users as a distinct opt-in and encoded accurately in the TCF consent string, rather than being bundled with ordinary Purposes. They should track revisions to the TCF specification, since the enumerated Special Features and signalling requirements are periodically updated by IAB Europe.
Legal counsel and compliance teams
Counsel advising on EU/EEA advertising operations should treat TCF Special Feature classifications as an industry standard that supports compliance but does not replace legal judgement. They should confirm that explicit opt-in is genuinely obtained where required and note that TCF definitions are EU/EEA-specific and may not map onto other jurisdictions' frameworks.

Inside Special Features

Special Features (TCF concept)
In the IAB Europe Transparency & Consent Framework (TCF), 'Special Features' are a defined category of data-processing operations that, because of their nature, always require user consent and cannot rely on legitimate interest. Unlike ordinary Features, they are surfaced separately in a CMP so users can specifically opt in or refuse them.
Distinction from ordinary Features
Ordinary TCF Features do not have their own legal basis; they piggy-back on the legal basis (consent or legitimate interest) chosen for the associated Purpose. Special Features differ in that they require their own explicit consent signal and are not available on a legitimate-interest basis.
Examples enumerated in TCF policy
The TCF policy documents enumerate the specific Special Features (for instance, operations involving the use of precise geolocation data and the active scanning of device characteristics for identification). Practitioners should consult the current TCF Policies for the authoritative, versioned list rather than relying on memory, as the enumeration can change between framework versions.
Consent signalling
Special Features are represented within the TCF's consent string and Global Vendor List structures so that vendors can read whether a user has opted in. A CMP that participates in the TCF must present these Special Features distinctly and record the corresponding consent.
Relationship to underlying law
The TCF is an industry framework that operationalises requirements derived from the EU GDPR and the ePrivacy Directive (and their national implementations). TCF categories such as Special Features are a contractual and technical convention; they support compliance but do not by themselves determine lawfulness, which remains a legal question under the applicable regimes.

Common questions

Answers to the questions practitioners most commonly ask about Special Features.

Is "Special Features" a term without a settled definition?
No. Special Features is an established concept within the IAB Europe Transparency & Consent Framework (TCF). In the TCF, Special Features are a defined category of data processing activities that, unlike ordinary Features, require the user's opt-in consent and cannot rely on legitimate interest. The term has a specific, documented meaning set out in the TCF Policies, so it should not be treated as ambiguous or undefined. Its scope is limited to the TCF context, and it does not carry a standalone meaning under the GDPR or ePrivacy Directive outside that framework.
Can Special Features rely on a transparency-only basis the way ordinary Features are sometimes described?
No, and this is a common point of confusion. In the TCF, ordinary Features do not have their own legal basis at all; they piggy-back on the legal basis (consent or legitimate interest) chosen for the Purpose they support, so transparency alone is not always sufficient even for ordinary Features. Special Features are treated more strictly: under TCF Policies they require the user's opt-in consent and cannot be based on legitimate interest. Treating Special Features as transparency-only would not reflect how the framework defines them.
How should a CMP present Special Features to users to obtain a valid signal?
Within the TCF, Special Features are surfaced through the consent management platform's user interface as items requiring an affirmative opt-in, separate from Purposes that may be based on legitimate interest. The CMP should present them in a way that lets the user make a specific, informed, and unambiguous choice through a clear affirmative action, consistent with GDPR consent standards in the EU. Beyond the technical mechanics of the signal, whether your particular presentation meets legal consent requirements depends on the surrounding disclosures and context, which fall outside the framework's technical specification and should be assessed with legal input.
Where are Special Features recorded in the TC String?
The TCF's Transparency and Consent String (TC String) encodes user choices for Purposes, Special Features, and other framework elements in a structured, machine-readable form that participating vendors read to determine what has been signalled. Special Features opt-ins are represented as their own set of values distinct from Purpose consents. For the exact encoding positions and field structure, consult the current TCF technical specifications rather than relying on a general description, as these details are versioned and may change between framework releases.
Do I need separate consent logging for Special Features?
The user's choices on Special Features form part of the consent record captured through the TCF signal, alongside Purpose choices. Maintaining records of consent is a general expectation under EU data protection practice, and where you rely on the TCF the TC String itself serves as evidence of the choices made. Whether your logging is adequate for accountability purposes depends on your broader record-keeping obligations, which vary by jurisdiction and are not resolved by the framework alone; treat the TCF signal as one input to, not a replacement for, your consent record-keeping strategy.
How do Special Features differ from Purposes when configuring vendor and CMP settings?
In the TCF, Purposes describe the reasons data is processed and may be configured for either consent or legitimate interest depending on the Purpose and vendor declarations. Special Features, by contrast, are a distinct category that requires opt-in consent and cannot be set to legitimate interest. When configuring vendors and your CMP, you should map which Special Features each vendor declares and ensure your interface collects opt-in for them separately from Purpose choices. The precise list of Special Features and the associated obligations are defined in the current TCF Policies, which should be consulted directly, and legal judgment remains necessary to confirm that your overall configuration meets applicable consent requirements in the relevant jurisdiction.

Common misconceptions

Special Features are just another name for ordinary TCF Features.
They are a distinct TCF category. Ordinary Features borrow the legal basis of their associated Purpose and may run under legitimate interest, whereas Special Features under the TCF always require explicit user consent and are presented separately in the consent interface.
Because a technology is TCF-listed as a Special Feature, using it is automatically lawful once the user opts in through a CMP.
The TCF is an industry framework that helps operationalise consent, but it does not guarantee compliance. Lawfulness still depends on the GDPR and the ePrivacy Directive (as implemented nationally) and on facts specific to each deployment. Data protection authorities may take differing positions, so the framework supports but does not replace legal judgment.
The list of Special Features is fixed and applies uniformly everywhere.
The enumeration is defined by IAB Europe's versioned TCF Policies and can change across framework versions. Moreover, the TCF primarily addresses EU/EEA requirements; obligations under the UK regime or individual US state laws (such as the CCPA/CPRA) differ and are not governed by this categorisation.

Best practices

Consult the current, versioned IAB Europe TCF Policies and Global Vendor List for the authoritative enumeration of Special Features rather than relying on outdated or remembered lists, as the set can change between framework versions.
Ensure your CMP presents Special Features separately from ordinary Purposes and Features so users can give a specific, unambiguous opt-in, consistent with the GDPR standard of consent that is freely given, specific, informed, and requires a clear affirmative action.
Do not treat Special Features as available on a legitimate-interest basis; configure your consent flows so that these operations proceed only where explicit consent has been captured and signalled.
Keep clear records of the consent obtained for each Special Feature, including the consent string, to support consent-logging and record-keeping obligations.
Remember that TCF participation supports but does not establish legal compliance; validate your use of geolocation, device-scanning, and similar technologies against the GDPR and the applicable ePrivacy implementation, and obtain legal review where interpretations are contested.
If you operate outside the EU/EEA, assess separately how UK and US state privacy regimes treat these processing activities, since the TCF's Special Features categorisation does not translate directly to opt-out-based frameworks such as the CCPA/CPRA.
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