The European Commission has opened a call for evidence on advertising repositories, the public databases that very large online platforms and search engines must keep under the Digital Services Act. Published on 4 November 2026, the exercise runs until 2 December and asks researchers, civil society groups, journalists and the advertising industry how those archives should be designed. The outcome will decide whether the databases become genuinely useful tools or remain a compliance formality.
Under Article 39 of the Digital Services Act, providers of very large online platforms and very large online search engines have to publish a repository of the advertisements they display. Each entry must show the ad content, who paid for it, the period during which it ran, the number of users it reached and the main targeting criteria. The Commission can issue guidelines on how these advertising repositories should work after consulting the European Board for Digital Services, researchers and the public, which is the step now under way.
The stated purpose is practical. Better advertising repositories would let researchers, journalists and national authorities spot scams, disinformation campaigns, misleading commercial practices and the promotion of illegal products or services. The guidelines are expected to focus on three areas: how easily the data can be searched, how much insight it gives into targeting and reach, and how accessible the ad content itself is. Each point addresses a familiar complaint that early archives were hard to query and incomplete.
The timetable shows a slow process. According to reporting based on the Commission’s page, a targeted public consultation on a draft text is planned for 2027, with final guidelines targeted for the second quarter of 2028. That leaves a long gap in which platforms keep running their existing archives under their own reading of the rules. Researchers who rely on the data will want to use the current call to push for concrete technical requirements rather than general principles.
For platforms, the stakes are commercial as well as legal. Advertising is the revenue engine of most very large online platforms, and a detailed record of targeting criteria exposes how campaigns reach audiences. Advertisers may worry about how much of their strategy becomes visible to competitors. The consultation therefore pits transparency goals against business confidentiality, and the Commission will need to draw that line carefully.
The call also fits a wider enforcement push on online advertising. Regulators have already questioned how platforms handle financial scams and misleading promotions, and a stronger evidence base would help national Digital Services Coordinators build cases. Clear guidance on advertising repositories would give them a common standard against which to measure compliance.
Anyone with a stake in how online advertising is policed has until 2 December to respond. The advertising repositories guidelines will shape what the public can see about who is paying to influence them, and the Commission has signalled that it wants practical input from the people who use the data every day.
