How-to guide: publisher installation of the ID5 ID module via Prebid

  • Posted by Alex Taylor
  • On Jun 27, 2022

If you’re a publisher considering integrating the ID5 ID, you may also be considering doing so via Prebid, the most widely used header bidding wrapper on the web., an engine that crawls 209,975 of the top websites, has identified that 100,043 of those publishers are using Prebid.

Prebid was launched in 2015 to simplify header bidding for publishers. It created an open tech layer where companies could add their code to a standard yet optimized foundation, thus making it easier to execute header bidding on websites and mobile apps.

Today, Prebid offers a suite of products, including Prebid.js, a header bidding platform containing over 300 demand sources and 50 analytics adapters and supporting common ID systems, GDPR, and various ad servers. Prebid.js contains the code needed for header bidding, while functionalities that could be considered add-ons are part of a module.

The User ID Module

User ID Module supports multiple ways of establishing pseudonymous IDs for users. This enables media owners to increase the value of header bidding and to leverage multiple IDs. Instead of integrating different IDs individually and having several exchanges sync IDs with several demand sources, publishers identify the modules that they want to use and add them to their Prebid.js package.

By leveraging this simple integration mechanism, media owners can test and compare different solutions and ultimately maximize addressability and monetization.

The ID5 ID is one of the identifiers available in the Prebid.js User ID Module and, according to, the ID5 ID is the most installed cookieless user ID module via Prebid.

Why should you integrate the ID5 ID via Prebid?

Prebid products are free and open-source, meaning anyone can contribute or review code and Prebid.js has the largest repository of header bidding adapters. Prebid offers numerous modules, tools, and analytics support to optimize publisher setup. For publishers wishing to test the effectiveness of the ID, Prebid has baked A/B testing directly into the module. The steps needed for publishers to integrate the ID5 ID via Prebid are simple and straightforward. Let’s take a look below.

Installing the ID5 ID module

  1. Register with ID5: Visit our website to sign up and request your ID5 Partner Number to get started.
  2. Add the ID5 submodule: via your Prebid.js package with:

gulp build –modules=id5IdSystem,userId

  1. ID5 recommends: The ID5 ID that is delivered to Prebid will be encrypted by ID5 with a rotating key to avoid unauthorized usage and to enforce privacy requirements. Therefore, we strongly recommend setting storage.refreshInSeconds to 8 hours (8*3600 seconds) or less to ensure all demand partners receive an ID that has been encrypted with the latest key, has up-to-date privacy signals and allows them to transact against it.

What are the benefits of using the ID5 ID?

Still need convincing on why to integrate the ID5 ID? The privacy-first ID is proven to improve audience addressability for publishers, as well as grow sustainable revenue across all environments without reliance on traditional identifiers. Don’t take our word for it, check out these case studies and see for yourself.

Integrating the ID5 ID provides many advantages for publishers, empowering them with:

  • Increased bid density and higher win rates, leading to better monetisation of traffic in environments where third-party cookies are not available
  • Privacy-by-design technology that respects and enforces privacy in the advertising value chain
  • Encryption mechanism ensuring that ID5 IDs are only shared with authorized partners 
  • Suitability for all web publishers regardless of the size of their authenticated audience

For more information, contact our dedicated publisher team at