Prebid and the User ID Module


This articles describes Prebid and the User ID Module and details adaptors and modules, optional features allowing custom functionality into the core prebid frameworks. 


Prebid commonly refers to the independent, global adtech organization and the open source header bidding software that they produce, maintain and promote. 

Header bidding is a programmatic advertising technique in which publishers bid on multiple advertising exchanges in real time to maximize CPM and yield of their media inventory. Previously the transactions between buyers and sellers of media inventory were made separately and in a sequence like a farmer manually taking his cart of produce to each of the grocery stores in town until one agrees to purchase his crop. 

Prebid provides an industry leading implementation of header bidding that publishers can easily add to their ad stack to support header bidding without having to develop all the integrations and management tools themselves. 

The group provides implementations of header bidding for client side, server side and mobile environments. The documentation in this section of the Lotame Knowledge Base will focus on the web based client side implementation.

The group supports extensibility into their products. Third parties can add custom functionality into the core prebid frameworks. Think of these like how you might use the core features of your web browser and add custom features by installing third party extensions. These optional features take the form of:

  • Adaptors

  • Modules


An Adapter connects the prebid instance and the data it manages to external parties. It is often, but not always, responsible for sending data out to offsite destinations. 

The two most common types of adapters are:

Bid Adapters, connections to the Sell Side Marketplaces or Exchanges where the combination of the site’s media inventory placements and their visitors are auctioned for sale. 

Analytics Adapters, connections to measurement tools and services to record market activity.  

The Bid Adapter is said to send the bid request to the auction where advertisers compete to buy the opportunity to run a display ad as part of their campaign in a specific placement. The path of bid request from the publisher to the auction is often referred to as the Bid Stream. Many requests flow from suppliers to buyers through multiple auctions and exchanges thanks to header bidding.


Modules are self contained extensions to prebid that perform tasks on the data that prebid sees or brings in useful data to be acted on. 

Modules perform a variety of functions from helping to manage pricing rules, currency conversions, viewability or Identity. Modules that provide identity allow different providers to attach their ID to the visitor for the purpose of identity resolution. Identity modules are implemented within Prebid using the User ID module feature.

User ID modules are used to pass a person, household or device level ID in the bid stream from the seller to the buyer auction. The value to both the buyers and sellers is that in addition to knowing where the placement is on the site, the context of other content that the visitor is exposed to, and a number of other attributes passed into the auction, that having a way to uniquely identify who the visitor is and understand data that has been previously associated to that person will make the winning ad impression more valuable to both parties. Without knowing much about who the auctioned ad placement is reaching means the price for that ad spot is low. While knowing who the winning ad is targeting means the seller can command a higher price from the right buyer.

The Lotame User ID Module

The Lotame User ID Module is designed to return the Panorama ID associated with the visitor on the page that the winning bid for a placement will target. 

The Lotame User ID module operates client side in the browser. The Lotame User ID module looks at locally stored locations for a Panorama ID that has been previously returned to the user or makes a request to the Lotame servers to retrieve a Panorama ID if one is not otherwise available. 

The Panorama ID accessed by the User ID module is then passed in the bidstream to the bid adapters that are specified in the sites' Prebid configuration.

SSP Support

The Panorama ID is passed to all active SSP bid adapters however the ID is only made available in those auctions if the Panorama ID is supported by the SSP. For a complete list of all SSPs that support the Lotame Panorama ID consult the list of adapters on the Prebid site.

At time of writing the supported SSPs are the following:




























For SSPs who wish to support the Lotame Panorama ID from a business arrangement point of view there is no requirement to contact or get approval from Lotame. Simply pick up the Lotame Panorama ID from the EID string in prebid. The EID or Extended Identifier is a key in the JSON User Object. Further information is available here:

Further background on the OpenRTB 3.0 specification is available here

Many of the supporting SSPs simply pick up all the IDs regardless of which ones they are. The ID is formally name:


The EID source domain for the ID is


The Lotame Panorama ID User ID Module for Prebid—Overview
How to Build Prebid From Source to Include The Lotame Panorama User ID Module
How to implement the Lotame User ID modules in Pubmatic
How to implement the Lotame User ID modules in Magnite
How to Implement the Lotame User ID Module in Smart AdServer
How to Test for the Lotame Panorama ID User ID Module in Prebid