What is Prebid timeout and how to optimize it?

Updated on: February 13, 2024
If your timeout duration is too long, your bidders won't miss the chance to respond, but your site can become slow. Additionally, your ads can take too much time to load, resulting in decreased viewability. On the other hand, if the duration is too short, more bidders wouldn’t be able to bid, resulting in less revenue. So, the prebid timeout duration should be optimum.

Prebid timeouts have different meanings in different contexts. Prebid’s official doc defines five types of timeouts, whereas if you talk to an adops person, the word ‘prebid timeout’ has only one meaning. It is the amount of time that prebid allows the bidders to respond to ad requests. Publishers can make changes to this timeout to optimize the performance of their ads. Let’s dig deeper.

What is Prebid timeout?

The header auction begins when a user loads a page on your site. Prebid sends bid requests to all the connected bidders. After receiving the request, demand partners (or bidders) are supposed to respond in a limited time frame. Prebid accepts only the responses that arrive within the time frame and rejects everything that comes later. The rejected responses are considered as timed out. So, when you say ‘prebid timeouts’ you refer to the time frame within which the bidders have to respond. The timeout value is passed along with the requestbids call:


    bidsBackHandler: sendAdserverRequest,

    timeout: 1000,

    labels: ["custom1"]


A timeout situation doesn’t include the case where a bidder decides not to bid. Even if a bidder isn’t interested in the auction, it’ll send a ‘no bid’ response. So, a bidder is considered as ‘timed out’ only when it cannot send a bid or ‘no bid’ within the predefined time frame.

What is the timeout rate in Prebid?

Publishers are interested in the timeout rate of their bidders because it shows how frequently their bidders fail to respond. For example, if a bidder received 100 requests and couldn’t respond to 20 of them because it timed out, it has a 20% timeout rate. If the timeout rate is unsatisfactory, you can allot more time to your bidders to improve it.

Why shouldn’t your bidders time out frequently?

Although it’s impossible to achieve, your bidders should ideally have a 0% time-out rate. It means they should never fail to respond to a bid request. When your bidder fails, it reduces the competition for your impressions and brings your revenue down. For example, bidder A could’ve bid $2 for an ad, but it timed out, so bidder B won the auction with just $1.5 because it was the next best bid. Here, you lost $0.5 because bidder A couldn’t respond in time.

While the problem looks minuscule when we look at a single auction, the losses add up when too many bidders are timing out frequently. 

Why do bidders time out?

Bidders can time out due to hundreds of reasons. For example:

  • An insufficient time limit for the bidder to respond.
  • Faulty integration with the wrapper.
  • Slow internet connection of the user.
  • Browser’s lack of power to parse your site quickly.
  • Improper CMP configuration.
  • Technical glitches on the bidder’s side.
  • Heavy load on the site.
  • Too many bidders in the auction, and many more.

How do you optimize your timeout?

Periodic Checkup

As a best practice, you can periodically check your site’s integration with all the technologies you’re using. Allowing more time to your bidders can also help. You can do so by tweaking prebid’s bidder timeout settings or pbjs.requestBids calls. But before doing so, it is important to know the risk. 

If your timeout duration is too long, your bidders won’t miss the chance to respond, but your site can become slow. Additionally, your ads can take too much time to load, resulting in decreased viewability. On the other hand, if the duration is too short, more bidders would miss the chance, resulting in less revenue. So, the prebid timeout duration should be optimum.

Use Analytics

Ask your peer publishers, and you’ll get varied responses to this question. From 500 milliseconds to 2000 milliseconds, the ideal prebid timeout can change from publisher to publisher. Start with your timeout rates. Prebid’s Analytics module can help you check it for each bidder. A short timeout duration makes most of the bidders fail. On the other hand, if only a single bidder is a slow responder, you’ll see it timeouts more than all the others.

Prebid timeout rate

Random Testing

Next, take random tests to find out how much time your bidders take. To do so, install the Headerbid Expert plugin on your Chrome browser and test different pages on your site. The plugin will show you how much time each bidder is taking, so you’ll get a rough idea to decide the ideal prebid timeouts for your setup. Be more granular to ensure the timeouts are not happening due to a particular device or the internet speed in a specific geography, etc. If so, set separate timeouts for such cases.


When you are working with third-party wrapper providers, ask them to keep an eye on your bidders. Wrapper companies work simultaneously with hundreds of sites, so they know more about specific bidders than any publisher with a few sites. Ask them to consider your site speed and user experience too. Ideally, a wrapper provider should have enough knowledge to keep your time outs at optimum levels. At Automatad, we are committed to the same goal. You can learn more about our ad operations here.

To sum it up:

How to optimize your prebid timeout?

  • Set a timeout that works with most of the bidders.
  • Don’t make it so long that your site slows down and ad viewability suffers.
  • Don’t keep it so short that most of your bidders are unable to keep up.
  • Pay attention to devices and geographies and set the timeout separately for the ones that are frequently lagging.
  • Keep your site light and fast so that you don’t have to increase your timeout.

What’s Next?

Many publishers don’t bother about their time-out because it takes meticulous observation and testing to perfect it. Many publishers set their time out between 1000ms to 2000ms, and it still works out for them. But, if you spend some time figuring out the best duration, it can noticeably improve your revenue and user experience. Even if you’re using a third-party header bidding wrapper, make sure it gives equal importance to Prebid time out.

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