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The First Step in Building a More User-Centric Internet

Where publishers control user privacy and their own data

Community Owned

SharedID, is managed by’s Publisher members. A free identity solution owned by the community rather than a vendor, delivers the trust and transparency required for widespread adoption across publishers and DSPs.

1st Party

Publishers can write the SharedID common identifier as a first-party value. SharedID stores a unique user ID, where the publisher can make the decision to either make this accessible to bidders, or use the user ID as a building block for publisher controlled first party self-declared data without the use of an identifier.

Preparing For A
Cookieless Internet

With SharedID, cookie syncing becomes unnecessary as every party in the ecosystem will utilize the same shared identifier. The industry will finally be freed from the reliance on hundreds of cookies, greatly reducing the overall identifier footprint.

The Start of Something Cool

SharedID gives the advertising industry a place for independent ad tech and publishers to test, iterate and share proposals to fix the issues our industry currently faces. By creating a foundational layer of what we have today, and what we could use tomorrow, is currently working on further proposals that align with our organizations main goals of keeping publishers in control of their data, protecting user privacy and rebuilding a better internet.


Replace your proprietary value and use SharedID for sandboxing.

Other Products

Prebid Server – open-source solution for server-to-server header bidding with Prebid.js and Prebid Mobile.

Prebid Mobile – open-source library that provides an end-to-end header bidding solution for mobile app publishers.

SharedID is an ID-generating service offered by Sharedid generates a globally unique first party identifier that publishers can use to identify unique users and to attach interest attributes to those users. However, it is not a third party identifier and as such does not have cross-site attributes. It is designed to be used in association with the Prebid product suite. SharedID does not involve the storage or processing of personal data by This document is to describe what SharedID is and how it works from a user privacy perspective. is an open source collaboration between companies involved in the ad-supported internet. It is a US corporation founded by a consortium of companies in the advertising technology and digital media businesses. members include publishers that show ads on their sites, advertisers and agencies that purchase advertising space and deliver ads to be shown, and the technology companies that facilitate the buying, selling, delivery, and measurement of the ads. was formed so that the companies could create transparent and standardized technologies for transacting and delivering ads. This standardization makes digital advertising more efficient and more transparent.

The first technology that Prebid created was a way for publishers to communicate about available ad space and for ad buyers to compete in a real-time unified auction for the opportunity to show an ad in the space. does not collect or use any personal information, but provides technology, standards, and policies or best practices that enable other companies to participate in the auctions. Those companies are responsible for their collection and use of data.

SharedID is ID-generating software that is maintained by Companies that participate in digital advertising typically use and share identifiers in order to better facilitate communication between the companies and to improve the targeting, delivery, measurement, etc. of ads. There are many different types of identifiers available, depending on the context. SharedID allows website operators to create an identifier with a standardized format — just a randomized number in a particular format — and store it in their own internet domain as a first-party browser cookie.

Companies take the Javascript computer code that provides, and they put it on their websites. The code generates a unique, random alphanumeric string, something like “6a345e65–5c1c-4400-bfbe-8de694eafcc1” referred to as a “SharedID”. The string, is it associated with a particular browser. They typically store the ID in a first-party cookie or browser local storage, and use it or share it in association with their advertising business. and SharedID do not store or have access to the identifier.

Once the website operator has created the ID, they can use it according to their own policies and applicable laws and rules. Typically, this means that the identifier gets passed in a request for an ad to be shown in an available ad space. Companies that receive the identifier can use it to remember information about user visits to the same website over time, and in turn that information is used for things such as counting the number of times a user sees the same ad, measuring ad performance, or targeting more relevant ads.

You may have certain rights and protections under applicable law regarding the processing of your personal data by the companies that use Prebid and SharedID. Prebid does not collect personal data in association with its suite of products, including SharedID. And is not responsible for data processed by companies using Prebid and SharedID.

If you have any questions about SharedID you may contact us by email at, Inc. 276 5th Avenue Suite 704 #756 New York, NY 10001

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