Overview
Cookie-syncing and identity resolution domain (operated by Nexxen, formerly Tremor International) that frequently appears in tag audits without the website operator having deployed it directly. Arrives via programmatic ad supply chains, header bidding wrappers, and third-party pixels, synchronising user identifiers across multiple advertising platforms. One of the most commonly flagged third-party tracking domains in European cookie audits, and a strong indicator that the organisation's ad supply chain requires closer governance scrutiny.
Detection capabilities
- Signature count
- 1
- Detection methods
- network
- Property types
- hostnamepathname
Performance impact
Performance Impact
- Requests per page
- 1
Common mistakes
- 1Not being aware that bidr.io cookies and requests are present on the website because they were introduced through programmatic supply chain partners rather than direct deployment
- 2Failing to block bidr.io cookie syncing before advertising consent is obtained, as header bidding scripts may load Bidr as a secondary dependency without explicit tag manager configuration
- 3Not including bidr.io in the cookie declaration because it appears as an unfamiliar third-party domain that is difficult to attribute to a specific vendor
- 4Assuming that blocking the primary advertising tag is sufficient when Bidr's cookie syncing may persist through other supply chain paths
- 5Not assessing the scope of cross-platform identity resolution performed by Bidr, which links user identifiers across multiple advertising platforms
Compliance considerations
Bidr (Nexxen/RhythmOne) sets third-party cookies and performs cross-platform cookie synchronisation that constitutes personal data processing under GDPR, requiring explicit advertising consent. The cookie syncing process shares user identifiers across multiple advertising platforms, which amplifies the privacy impact. Bidr's presence on a website often indicates broader programmatic supply chain exposure that should be audited comprehensively. Under the ePrivacy Directive, third-party cookie syncing clearly requires consent. Organisations should audit their programmatic advertising stack for Bidr domains, ensure all supply chain partners are covered by the CMP advertising consent category, and include bidr.io in their cookie declaration. Nexxen processes data in the United States and should be assessed against EU-US Data Privacy Framework requirements.
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