Key Takeaways

• Default prebid timeout settings (1000ms) are often too short for optimal revenue

• Mobile devices generally need longer timeouts than desktop (1500-2000ms vs 1000-1500ms)

• A/B testing different timeout values is essential for finding your site's optimal settings

• Advanced configurations like dynamic timeouts can further optimize performance

• Monitoring timeout rates per bidder helps identify underperforming demand partners

Understanding Prebid Timeouts: The Revenue-Performance Tightrope

Publishers using header bidding face a constant dilemma - wait longer for more bids and potentially higher revenue, or prioritize page speed for better user experience? This tension is precisely what makes finding the perfect prebid timeout setting both crucial and challenging.

Think of prebid timeouts like waiting for people to arrive at a party. End the party too soon, and you miss out on the big spenders who arrive fashionably late. Wait too long, and your early guests might get bored and leave.

In header bidding, you're literally deciding how long to pause your page's ad loading process while waiting for bids to arrive. And that timing decision has direct implications for both your revenue and your site's performance.

"The mistake many publishers make is accepting default timeout settings without testing what works best for their specific traffic and demand partners," says Ryan Buckley, CTO at Freestar, who's obsereved that optimal settings vary greatly by publisher.

The Technical Fundamentals of Prebid Timeouts

Before getting into optimization tactics, let's clarify what we're actually talking about when we discuss "prebid timeouts." For those new to header bidding, there are actually several different timeout settings that work together:

Auction Timeout

This is the primary timeout setting most publishers focus on. It determines how long Prebid.js waits for bids before sending whatever bids it has collected to the ad server.

pbjs.setConfig({
  bidderTimeout: 1500  // In milliseconds
});

The default is typically 1000ms (1 second), but as we'll discuss, this is rarely optimal.

Failsafe Timeout

This is a safety mechanism that ensures the ad request eventually gets sent to the ad server, even if something goes wrong with Prebid.js. It should always be set higher than your auction timeout.

googletag.pubads().enableSingleRequest();
googletag.pubads().disableInitialLoad();
googletag.pubads().setSafeFrameConfig({allowOverlayExpansion: true});
var failsafeTimeout = 2000; // 2 seconds

S2S Timeout (Server-to-Server)

If you're using Prebid Server for server-side header bidding, you'll also need to consider the s2sConfig timeout. This should be set lower than your auction timeout to account for the additional communication time between servers.

pbjs.setConfig({
  s2sConfig: {
    timeout: 800  // Lower than auction timeout
    // Other s2s configurations
  }
});

How Timeout Settings Impact Revenue and Performance

Timeout settings create a direct tradeoff between two important metrics:

Revenue Impact:

• Too short: Some demand partners won't respond in time, meaning fewer bids and potentially lower prices

• Optimal: All major bidders have time to respond, creating maximum competition

• Studies show: Extending timeouts from 1000ms to 1500-2000ms can increase revenue by 5-8%

Performance Impact:

• Too long: Page load time suffers, potentially hurting SEO, Web Vitals scores, and user experience

• Significant concern: Long timeouts can negatively impact Largest Contentful Paint (LCP) scores

• Real-world impact: Every additional 100ms of load time can reduce conversion rates by ~1%

Finding Your Optimal Timeout: Step-by-Step Guide

Instead of giving you a magic number that works for everyone (spoiler: it doesn't exist), here's a methodical approach to determine the right timeout settings for your specific site:

1. Analyze Your Current Bidder Response Times

Before making any changes, gather data on how quickly your current demand partners respond:

pbjs.onEvent('bidResponse', function(bid) {
  console.log(bid.bidderCode + ' responded in ' + (Date.now() - pbjs.auction.getAuction(bid.auctionId).auctionStart) + 'ms');
});

This simple code addition will log each bidder's response time, giving you valuable insights about which partners might be getting cut off by your current timeout.

2. Segment Analysis by Device Type

Mobile connections are typically slower than desktop, so analyze your data separately by device type. Many publishers find they need different timeout strategies for different devices:

"We saw a 5.7% revenue lift simply by increasing our mobile timeout from 1000ms to 1750ms while keeping desktop timeout at 1200ms," reports Sarah Chen, Ad Ops Director at MidwestPublishing.com.

3. Set Up A/B Testing

The only way to truly find your optimal timeout is through structured A/B testing:

1. Create two identical setups with different timeout values

2. Run them for at least a week, alternating between the two versions

3. Compare key metrics: revenue, bid rate, timeout rate, and page performance

Your goal is to find the point where additional wait time no longer brings in enough incremental revenue to justify the performance hit.

4. Monitor Core Web Vitals

While testing different timeout settings, keep a close eye on your Core Web Vitals metrics, especially:

• Largest Contentful Paint (LCP): Should be under 2.5 seconds

• First Input Delay (FID): Should be under 100ms

• Cumulative Layout Shift (CLS): Should be under 0.1

If your timeout settings are hurting these metrics significantly, you'll need to find a better balance, as poor Core Web Vitals can hurt both SEO and user experience.

Advanced Timeout Optimization Strategies

Once you've found your baseline optimal timeout, consider these advanced tactics:

Dynamic Timeouts Based on User Connection

Adjust timeout settings based on the user's connection type using the Network Information API:

if (navigator.connection && navigator.connection.effectiveType) {
  switch(navigator.connection.effectiveType) {
    case '4g':
      pbjs.setConfig({ bidderTimeout: 1200 });
      break;
    case '3g':
      pbjs.setConfig({ bidderTimeout: 1800 });
      break;
    default:
      pbjs.setConfig({ bidderTimeout: 2000 });
  }
}

Per-Bidder Timeout Settings

Some advanced prebid setups allow different timeouts for different bidders based on their typical response times:

pbjs.setConfig({
  bidderSequence: 'random',
  bidderTimeout: 1500,
  bidderSettings: {
    slowBidder: {
      bidCpmAdjustment: function(bidCpm) {
        return bidCpm * 0.95;
      },
      timeout: 800  // Custom timeout for this bidder
    }
  }
});

While this technique isn't officially supported in all Prebid versions, similar functionality can be achieved through custom adapter modifications.

Progressive Timeout Reduction

For sites with recurring visitors, consider a progressive approach:

1. First pageview: Longer timeout (e.g., 1800ms) to maximize revenue

2. Subsequent pageviews: Shorter timeout (e.g., 1200ms) to improve experience

This can be implemented using browser storage to track visit counts.

Real-World Examples & Results

Here's how different types of publishers have optimized their prebid timeouts:

News Publisher Case Study

A large news site with 15M monthly pageviews tested five different timeout settings (800ms, 1000ms, 1200ms, 1500ms, and 2000ms) across desktop and mobile.

Results:

• Desktop optimal: 1200ms (3.2% revenue increase vs 1000ms)

• Mobile optimal: 1800ms (7.1% revenue increase vs 1000ms)

• Web Vitals impact: Negligible at these values

• Timeout settings past these values showed diminishing returns

E-commerce Publisher Example

An e-commerce site prioritizing page speed over incremental revenue found their sweet spot at:

• Desktop: 900ms

• Mobile: 1300ms

This shorter timeout ensured faster product page loads, which was crucial for their conversion funnel. The slight revenue decrease was offset by improved conversion rates.

Common Pitfalls to Avoid

As you optimize your timeout settings, watch out for these common mistakes:

1. Setting and forgetting: Optimal timeouts change as your bidders, traffic, and technology evolve

2. One-size-fits-all approach: Different sections of your site may benefit from different timeout strategies

3. Ignoring seasonality: During high-demand periods (Q4), longer timeouts may be more valuable

4. Focusing only on revenue: Consider the full user experience impact of your timeout decisions

Implementation Checklist

To summarize the process of optimizing your prebid timeout settings:

1. ⬜ Gather current bidder response time data

2. ⬜ Segment analysis by device type

3. ⬜ Set up A/B testing framework

4. ⬜ Monitor Core Web Vitals during testing

5. ⬜ Evaluate revenue vs performance tradeoffs

6. ⬜ Implement optimized timeouts (likely between 1000-2000ms)

7. ⬜ Consider advanced strategies like dynamic timeouts

8. ⬜ Schedule regular re-testing (quarterly)

Conclusion: The Balanced Approach Wins

Finding the optimal prebid timeout isn't about maximizing either revenue or performance - it's about finding the perfect balance for your specific situation. The right timeout settings act as a pressure valve, releasing just enough performance to gain meaningful revenue without compromising user experience.

Remember that this balance point will shift over time as your traffic patterns change, as bidders improve their response times, and as browser technology evolves. Make timeout optimization a regular part of your ad operations routine, and you'll maintain that ideal balance between revenue and performance.

Frequently Asked Questions

What is the default prebid timeout setting?

The default setting in Prebid.js is typically 1000ms (1 second), though many publishers find this to be too short for optimal revenue.

How often should I re-evaluate my timeout settings?

At minimum, quarterly reviews are recommended, with additional testing after any major traffic shifts or when adding new demand partners.

Do I need different timeout settings for different ad units?

While possible, most publishers find that device-type segmentation (desktop vs. mobile) provides sufficient optimization without overly complicating implementation.

How can I tell if my timeout settings are too short?

Monitor your timeout rate by bidder. If certain bidders consistently time out more than 20-30% of the time, your settings may be too aggressive.

Will longer timeouts always increase revenue?

No. There's a diminishing return curve - at some point, waiting longer brings minimal additional bids while unnecessarily delaying page rendering.

Additional Resources:

• Prebid Documentation: Video Introduction to Timeouts

• PubPower: What is Prebid Timeout and How to Optimize It

• Mile.tech: Understanding and Optimizing Prebid Timeouts