Understanding the Rewarded Interest ID Module in Prebid.js: A Practical Guide for Publishers
User identity is at the heart of effective header bidding and programmatic advertising. However, traditional identity solutions are under increasing scrutiny due to privacy regulations and browser changes. Publishers face a tough balancing act: maximize addressability and yield, while respecting user privacy and evolving identity frameworks.
The Rewarded Interest ID module in Prebid.js offers a privacy-centric approach through a user-enabled identity mechanism. In this post, we’ll break down how it works, why it matters, and what integration means for your operations and revenue strategies.
What Is the Rewarded Interest ID and How Does It Work?
The Rewarded Interest ID is an identity solution designed to give users direct control over their advertising identifier. Unlike conventional IDs that track users passively, the Rewarded Interest approach requires explicit participation. Users install a browser extension and opt in to share an encrypted identity token with ad providers via Prebid.js.
When a user visits your site and has the Rewarded Interest extension enabled, Prebid.js includes their encrypted identity token in the oRTB (Open Real-Time Bidding) request. This token is both privacy-protecting and persistent, refreshing frequently to preserve anonymity and minimize risk of misuse. Importantly, the identity token itself can’t be used to identify the user directly. Instead, demand partners rely on the Rewarded Interest Identity Resolution API to translate the token into a CMAID (Consumer Mediated Advertising Identifier)—a durable, cross-device advertising ID linked to the user’s involvement.
Key Implementation Details for Publishers
– The Rewarded Interest ID only appears in bid requests if the user:
– Has installed the Rewarded Interest browser extension
– Has authorized sharing of the identity
– Publishers must add the ‘rewardedInterestIdSystem’ submodule to their Prebid.js build.
– Configuration is minimal; typically, it’s just adding the module name in your Prebid userSync config.
– If the extension is absent or unauthorized, no identity token is sent—ensuring user privacy is always respected.
Integrating the Rewarded Interest ID into Your Prebid.js Setup
Adding the Rewarded Interest ID module to your existing Prebid.js wrapper is straightforward, but there are a few technical details to keep in mind.
Build and Configuration Example
1. Include the module in your Prebid.js custom build command:
gulp build –modules=userId,rewardedInterestIdSystem
2. Update your Prebid.js config as follows:
pbjs.setConfig({
userSync: {
userIds: [{ name: ‘rewardedInterestId’ }]
}
});
3. No additional parameters or consent hooks are required beyond the basics. The module will automatically detect eligible users and handle the rest.
This minimal configuration reduces errors and maintenance overhead. However, you should verify correct integration by checking bid requests for the identity token during QA.
Real-World Use Cases and Publisher Considerations
Understanding how the Rewarded Interest ID fits into everyday publisher workflows is crucial for adoption and troubleshooting.
Example: Header Bidding Flow with Rewarded Interest ID
– User lands on a page with Prebid.js and the Rewarded Interest browser extension installed.
– Prebid.js recognizes the extension, collects the encrypted identity token, and attaches it to the bid request.
– Demand partners who support Rewarded Interest resolve the token into a persistent, cross-device advertising identifier (CMAID).
– If the user pauses or resets their identity in the extension, the token stops resolving, reflecting user control immediately.
– If the extension is missing or sharing is not authorized, no ID is included, and fallback identity solutions must be relied upon.
Common Publisher Pitfalls
– Expecting the module to deliver an ID for all users—The identity is only available to users who have installed and authorized the browser extension.
– Overlooking the importance of clear user messaging—If you want maximum coverage, consider educating users about the extension and its privacy benefits.
– Not monitoring for ID presence in requests—QA your Prebid.js implementation to ensure the rewardedInterestId appears as expected for eligible users.
What this means for publishers
Operationally, the Rewarded Interest ID supports publisher goals of privacy compliance and sustainable addressability. It empowers users to opt in actively, which can help both with building trust and with meeting regulatory requirements. Publishers should expect coverage for a small but privacy-conscious segment of users. You’ll want to consider Rewarded Interest as part of a broader identity strategy, supplementing conventional modules and server-to-server ID solutions.
Practical takeaway
For most publishers, integrating the Rewarded Interest ID module is an easy lift—add it to your Prebid.js build and configure it in userSync. However, adoption among users is the critical limiting factor. If your audience overlaps with privacy advocates or tech-savvy users, the module adds real value and credibility.
Best practice is to treat Rewarded Interest as a privacy-first complement to other universal or deterministic IDs. Monitor ID presence in your logs, educate your team, and consider messaging your users if you want more impact. In a world of evolving privacy norms, enabling user-driven identity is a smart hedge that positions your stack for the future.
