Prebid is one of the most popular header bidding solutions for publishers. It helps maximize competition for ad impressions and increase revenue. But one of the most overlooked settings in Prebid is the timeout. Timeout defines how long the auction waits for bids before passing it to the ad server. If it is not set correctly, publishers can lose money, slow down their sites, or frustrate users.
Here are five common timeout mistakes publishers make and how to fix them.
1. Setting the Timeout Too Short
Mistake: A very short timeout does not give demand partners enough time to respond. This means fewer bids are considered, and impressions may go unsold or filled at lower prices.
Fix: Test different timeout values to find the right balance. Many publishers see good results between 1500 and 2500 milliseconds, but the ideal number depends on your site speed and partner response times. Use reporting tools to measure how changes affect fill rate and CPM.
2. Setting the Timeout Too Long
Mistake: A very long timeout delays the page load and hurts user experience. Visitors may leave before the ad loads, which reduces viewability and revenue.
Fix: Keep timeouts reasonable. Do not set them longer than necessary. Monitor page speed and user engagement alongside ad revenue to make sure your settings do not harm the overall site experience.
3. Ignoring Network and Device Differences
Mistake: A single timeout value may work well for desktop users on fast connections, but fail for mobile users on slower networks. This leads to lost bids and lower CPMs for mobile traffic.
Fix: Adjust timeouts based on device and geography. Mobile users may need slightly longer timeouts, while desktop users can work with shorter ones. Use analytics to compare performance across segments and fine-tune accordingly.
4. Not Reviewing Timeout Settings Regularly
Mistake: Publishers often set a timeout once and never revisit it. Over time, partner performance, site speed, and user behavior change. Outdated settings can reduce revenue.
Fix: Review timeout settings regularly. Run A/B tests to see if adjustments improve performance. Keep track of changes in partner response times and update your configuration when needed.
Why Timeout Settings Matter
Before diving into mistakes, it is important to understand why timeout settings are so critical.
- Revenue impact: If the timeout is too short, demand partners may not have enough time to respond. This reduces the number of bids considered and lowers competition, which can lead to lower CPMs.
- User experience: If the timeout is too long, ads take longer to load. Slow ads hurt page speed, frustrate users, and reduce viewability.
- Balance of priorities: Publishers must balance the need for higher revenue with the need for fast, responsive sites. Timeout settings are the key to striking this balance.
With this context, let us look at the five most common mistakes publishers make with Prebid timeouts.
Practical Example
Let us consider a publisher with 1 million monthly impressions. They initially set their Prebid timeout at 400 milliseconds. Only half of their partners consistently respond in time, and their average CPM is $1.20.
After testing, they increased the timeout to 1000 milliseconds. Now, 80 percent of partners respond, and the average CPM rises to $1.50. That is an extra $300 per month in revenue, or $3600 per year, simply from adjusting one setting.
They also notice that mobile users in certain regions still experience slow load times. By setting a slightly longer timeout for mobile traffic, they capture more bids without hurting user experience.
This example shows how small changes in timeout settings can have a big impact on revenue.
Common Questions About Prebid Timeouts
How do I know if my timeout is too short?
If you notice low fill rates, fewer bids being considered, or certain demand partners rarely winning auctions, your timeout may be too short. A short timeout cuts off slower partners before they can respond, which reduces competition and lowers CPMs. For example, if you set a 400ms timeout and half your partners consistently need 800ms, you are losing potential revenue. The fix is to test longer timeouts and measure how fill rate and CPM change.
How do I know if my timeout is too long?
If your site feels sluggish, ads load late, or viewability drops, your timeout may be too long. Long timeouts delay page rendering, which frustrates users and reduces engagement. Advertisers also pay less for ads that load late because viewability scores decline. For instance, a 2000ms timeout may allow more bids, but if users bounce before the ad loads, you lose revenue anyway. The fix is to balance revenue gains with user experience by testing shorter timeouts and monitoring page speed.
How often should I review my timeout settings?
At least once a quarter, but ideally more often if you notice changes in performance. Partner response times, site speed, and user behavior evolve over time. A timeout that worked six months ago may no longer be optimal today. Regular reviews help you stay aligned with market conditions. For example, if you add new partners or see traffic growth from mobile users in regions with slower networks, you may need to adjust timeouts accordingly.
Final Thoughts
Timeouts may seem like a small detail, but they have a big impact on Prebid performance. Setting them too short or too long can cost publishers money and hurt user experience. By testing, segmenting, and reviewing timeout settings, publishers can make sure they capture the maximum value from every impression.
