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ID5

ID5

Identity solution provider for the programmatic advertising industry. ID5 scripts establish a shared user identifier that persists across publisher sites and DSPs without relying on third-party cookies, enabling audience-targeted advertising in a privacy-compliant way.

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Overview

ID5 is an identity solution provider for the programmatic advertising ecosystem. It generates a shared user identifier that persists across publisher sites and demand-side platforms, enabling audience-targeted advertising without relying on third-party cookies.

What This Script Does

  • Generates and stores a universal user ID (ID5 ID) using first-party cookies and other identity signals
  • Syncs the ID5 ID with participating DSPs, SSPs, and data platforms via cookie syncing and API calls
  • Sets first-party cookies to persist the identifier across visits to the same publisher site
  • Integrates with Prebid.js as a User ID Module, making the ID5 ID available to bidders during header bidding auctions
  • Collects browser signals (IP address, user agent, device characteristics) to generate probabilistic identity graphs

Consent & Compliance

  • Consent category: Marketing
  • GDPR/ePrivacy: ID5 creates a persistent cross-site identifier used for advertising purposes. Requires explicit opt-in consent under ePrivacy (cookie consent) and GDPR (processing for advertising). ID5 participates in the IAB TCF as a registered vendor.
  • CCPA: The ID5 identifier enables cross-site identification for advertising, which likely constitutes "sale" of personal information. Honor opt-out signals.

Should You Block This Without Consent?

Yes. ID5's sole purpose is to create a persistent advertising identifier that enables cross-site user tracking for programmatic advertising. It must not load without explicit marketing consent.

Is ID5 GDPR compliant?

ID5 typically loads marketing trackers, which are not strictly necessary for your site to work. Under the GDPR and the ePrivacy Directive, non-essential cookies and trackers must stay blocked until a visitor gives clear opt-in consent. So ID5 can be fully GDPR compliant, but only if your site holds its scripts until consent is granted and lets visitors decline just as easily. Compliance depends on how your site loads ID5, not on ID5 itself.

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Consent Categories

Marketing

Also Known As

ID5 identityID5 universal IDcookieless identityID5 GDPRshared user ID advertisingid5-sync

Industries

Computers Electronics and Technology

Tracked Domains (1)

ID5's trackers are common, seen on about 13% of the sites ConsentStack has scanned. Scan your own site to see which of these are firing before consent.

id5-sync.comMarketing

id5-sync.com is a marketing domain operated by ID5, used to serve ads, build audiences, and measure ad conversions. Seen on about 13% of scanned sites.

Frequently Asked Questions

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