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Debugging Prebid.js

Use these commands in your browser console to inspect and debug Prebid.js configurations.

How to Use These Commands

  1. Open the webpage you want to debug
  2. Open browser's developer tools (F12 or right-click → Inspect)
  3. Click on the "Console" tab
  4. Copy a command and paste it into the console
  5. Press Enter to execute
Results will vary depending on the site's Prebid.js implementation.

View All Prebid Configurations

pbjs.getConfig();

Displays the complete Prebid.js configuration object with all settings.

View All Bid Responses

pbjs.getBidResponses();

Shows all auction responses from bidders, including CPM, size, and ad server targeting.

View Winning Bids

pbjs.getAllWinningBids();

Shows only winning bids across all auctions.

View Configured Ad Units

pbjs.adUnits;

Displays all ad units configured for Prebid auctions.

View Ad Server Targeting

pbjs.getAdserverTargeting();

Shows key-value pairs sent to the ad server for targeting.

Explore Full Prebid Object

pbjs.que.push(function () {
  console.log(pbjs);
});

Logs the entire Prebid.js object to explore all properties and methods.

Enable Debug Mode

Turns on verbose console logging for Prebid events.

For a Specific Page View

Add pbjs_debug=true to the URL's query string:

https://yoursite.com/page?pbjs_debug=true

Example:

/pbjs_demo.html?pbjs_debug=true

Programmatically

Enable debug mode from the browser console:

pbjs.setConfig({ debug: true });

For more information, see the Prebid.js troubleshooting guide.

Common Issues

No Bids Returned

Symptoms:

  • Empty bid responses
  • Ad units not filled
  • Console shows no bid activity

Debugging Steps:

  1. Check if Prebid.js is loaded:
typeof pbjs !== "undefined";
  1. Verify ad units are defined:
pbjs.adUnits;
  1. Check adapter configuration:
pbjs.getBidderConfig();
  1. Inspect network requests in the Network tab for bidder endpoints

Common Causes:

  • Incorrect bidder parameters
  • Invalid placement IDs
  • Ad blockers interfering
  • Timeout too short
  • Invalid ad sizes

Timeout Issues

Symptoms:

  • Bids arriving after timeout
  • Incomplete auction results

Check Current Timeout:

pbjs.getConfig("bidderTimeout");

Increase Timeout:

pbjs.setConfig({
  bidderTimeout: 3000, // 3 seconds
});
Longer timeouts allow more bids but delay ad rendering. Find the right balance for your setup.

Adapter Not Working

Verify Adapter is Included:

pbjs.installedModules;

This lists all installed Prebid.js modules. Ensure your bidder adapter is in the list.

Check Adapter Configuration:

// Get configuration for specific bidder
pbjs.getBidderConfig("bidderName");

Price Granularity Issues

Check Current Price Granularity:

pbjs.getConfig("priceGranularity");

Common Granularity Settings:

  • "low" - $0.50 increments
  • "medium" - $0.10 increments up to $20
  • "high" - $0.01 increments up to $20
  • "auto" - Sliding scale
  • "dense" - More granular buckets

Network Debugging

Inspect Bid Requests

  1. Open browser DevTools (F12)
  2. Go to the Network tab
  3. Filter by your bidder domain (e.g., prebid.openx.net)
  4. Click on the request to view:
    • Request payload (ad unit details, sizes, etc.)
    • Response body (bid responses)
    • Headers

Check for Failed Requests

Look for:

  • 400 errors (bad request - check parameters)
  • 403 errors (forbidden - check account/placement IDs)
  • 404 errors (not found - check endpoint URLs)
  • Timeout/cancelled requests

Advanced Debugging

Bidder Specific Debugging

Some bidders have their own debug modes:

pbjs.setConfig({
  debug: true,
  appnexusAuctionKeywords: {
    debug: ["true"],
  },
});

Check your bidder's documentation for specific debug options.

Event Listeners

Monitor Prebid.js events:

pbjs.onEvent("auctionEnd", function (args) {
  console.log("Auction ended:", args);
});

pbjs.onEvent("bidWon", function (bid) {
  console.log("Bid won:", bid);
});

pbjs.onEvent("bidTimeout", function (timedOutBids) {
  console.log("Bids timed out:", timedOutBids);
});

Available events:

  • auctionInit - Auction starts
  • auctionEnd - Auction completes
  • bidRequested - Bid request sent
  • bidResponse - Bid response received
  • bidWon - Bid wins the auction
  • bidTimeout - Bid times out

Verbose Logging

Get extremely detailed logs:

pbjs.setConfig({
  debug: true,
  enableSendAllBids: true,
});

Testing Tools

Professor Prebid Chrome Extension

Install the Professor Prebid extension to visualize:

  • Real-time bid data
  • Auction timelines
  • Bidder performance
  • Configuration issues

Manual Testing

Test specific scenarios:

pbjs.requestBids({
  adUnitCodes: ["specific-ad-unit"],
  bidsBackHandler: function (bids) {
    console.log("Test auction complete:", bids);
  },
});

Performance Monitoring

Check Auction Duration

pbjs.onEvent("auctionEnd", function (auction) {
  console.log("Auction duration:", auction.auctionEnd - auction.auctionStart, "ms");
});

Monitor Bidder Timeouts

Track which bidders consistently timeout:

pbjs.onEvent("bidTimeout", function (timedOutBids) {
  timedOutBids.forEach(function (bid) {
    console.log("Timeout:", bid.bidder, bid.adUnitCode);
  });
});

Support Resources

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