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.

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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-sync.comMarketing

Frequently Asked Questions

Does ID5 require cookie consent?

Yes. ID5 is a shared identity infrastructure that creates persistent user identifiers for cross-site ad targeting and frequency capping. Under GDPR, deploying ID5 requires explicit marketing consent. CCPA requires opt-out. It is classified under the marketing consent category.

What cookies does ID5 set?

ID5 sets a first-party cookie (id5id) and syncs with third-party ad tech partners via the id5-sync.com domain. The identifier persists for up to 90 days and is used to link user sessions across publishers for programmatic advertising and audience matching.

How does ConsentStack handle ID5?

ConsentStack detects ID5 by its script patterns and the id5-sync.com domain, classifying it as a marketing vendor. Without marketing consent, ConsentStack blocks ID5 from setting its identifier cookie. When consent is granted, ID5 loads and begins cross-site identity resolution.

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Manage consent for ID5

ConsentStack automatically detects and manages ID5 trackers so your site stays compliant with global privacy regulations.

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