Professor Prebid User Guide


Professor Prebid is an open source Chrome extension to allow easy debugging and troubleshooting on publisher websites using Prebid.js.


Simply visit the dedicated Chrome Store link and click on Add to Chrome. Don’t forget to pin it so you can have one-click access.

Alternatively, if you want to compile it yourself and run locally, please clone Github’s repository and follow the instructions.


Professor Prebid will automatically detect if the page has one or more Prebid instances. It Prebid is found, the extension’s icon will display a badge like: alt_text

Click on the icon to start interaction.



This is the default view and allows you to quickly check all the adunit codes available to Prebid, along with the associated media types and bidders.

Professor Prebid AdUnits screen

Each bidder entry is clickable, showing the associated input and bid response. You can easily copy a specific part of the JSON to the clipboard.

AdUnits screen bidders detail

Finally, you can also spot who is the winning bidder and whether its ad was rendered. AdUnits screen winning bidder


This screen allows you to verify and compare all the bids placed via Prebid.js and their metadata including:

  • Bid value
  • Bid currency
  • Response time
  • Adserver Targeting keywords

Professor Prebid bids screen


This view shows you the auction’s main milestones:

  • Auction start timestamp
  • Bidders calling sequence and timestamp
  • Each bidder response time
  • Timeout threshold
  • Auction end timestamp

Professor Prebid timeline screen

Professor Prebid renders different timeline views using the auction id as key. This can happen if the publisher has an auto-refresh or manages each adunit independently.


You will find here the main modules and their configuration:

  • Price Granularity: low/medium/high/auto/dense/custom
  • Bidder settings: calling order, timeout, …
  • Prebid Server: id, bidders, endpoints, …
  • CMP: Support different compliance frameworks (TCF, CCPA…), encoded consent string, decoded consent string
  • User ID modules

Professor Prebid config screen

User ID

This view displays the configuration and the outcome of the different id providers found on page.

Professor Prebid user ID screen


This tab provides advanced troubleshooting tools:

  • Shortcut to GAM console
  • Activation of Prebid Debug data on console
  • Bid filtering: allowlist of bidders
  • Bid CPM override
  • Adunit overlay: shows details about the winner over the creative on page

Professor Prebid tools screen

Here’s an example of an overlay:

Overlay example

How can I submit a feature request ?

Please open an GitHub issue on

How can I report a bug ?

Please submit a GitHub issue on providing as much details as possible:

  • Steps to reproduce the issue
  • Example of website where you face the issue
  • Professor Prebid version