Prebid Timeouts

Header bidding needs some time to collect bids. Publishers update their pages to delay the ad server call for just long enough to get bids, but not so long as to reduce overall revenue. This delay is controlled by a number of timeouts and adjustments.

Open

Client side: Timeouts are divided into Auction Timeout and Failsafe Timeout. They can be configured in atf-tagmanager individually per publisher in Publisher → Bidders → Prebid.

For all Publisher Auction Timeout is 1000 ms and Failsafe Timeout 3000 ms at the moment.

The only timeout we don't set is the Timeout Buffer (default value is 400ms).

Auction Timeout: This value defines the amount of time the page has to coordinate the header bidding activities. Determining this value is a delicate balance: too short, and header bidding won’t have enough time to take place; too long, and revenue may go down due to delaying the ad server call to the point where users have left the page.

Failsafe Timeout: It’s a safety net that invokes the ad server callback in case something goes wrong. In all regular scenarios, Prebid.js will have already invoked the callback before this timeout is reached. This value should be much larger than the auction timeout.

Timeout Buffer: The JavaScript timer environment is not perfectly accurate because competing JavaScript on the page can delay the header bidding auction or the recognition that auction results have returned. By default, Prebid.js adds a 400ms buffer to the Auction Timeout to account for the noisy environment.

By default, timeouts are not sent to the Bidders, but they are able to read them themselves, probably for optimization purposes.

Server side: This is a global timeout for each publisher, which can also be set in atf-tagmanager in the Settings → Prebid → SERVER CONFIGURATION → Timeout (this is tmax param in request)

Prebid Server s2sConfig Timeout: In order to make sure that Prebid Server bids can get back to the client in time for the ad server call, publishers should consider setting s2sConfig Timeout to a value lower than the Auction Timeout. How much lower depends on average user network delay, but should probably be within the range of 50%-75% of the Auction Timeout. This value is sent in the Prebid Server OpenRTB as tmax.

For all Publishers tmax is 500 ms.

tmax takes place shortly after the auction timeout is started and it takes place during the auction timeout, so it should be shorter than the auction timeout. tmax is a parameter passed only for prebid server and I am not sure if s2s adapters are able to read this value

"Timeout Adjustment" is set on the prebid server config and is not explicitly displayed. We don't set this timeout anywhere, so it assumes a default value of 10 ms prebid-server/config/config.go at 0.127.0 · prebid/prebid-server.