What is bid rate?
Bid rate is the share of bid requests to which a bidder responds with at least one bid, calculated as requests bid on divided by requests received. Exchanges track it per bidder to decide how much traffic to send, and bidders track it to see whether their campaigns match the supply. A low bid rate means most requests are being passed on, for good reasons or bad ones.
Also called: bid response rate, bidder response rate.
How it works
From the exchange side, a request answered with HTTP 204, an empty BidResponse.seatbid, or a response holding only BidResponse.nbr counts as a no-bid. Responses that arrive after BidRequest.tmax are usually counted as timeouts rather than no-bids, so the two rates should be tracked separately. Many exchanges send less traffic to bidders that rarely bid, which makes a falling bid rate self-reinforcing.
Bidders control the denominator through pretargeting and the QPS limit agreed with each exchange, and the numerator through campaign logic. A request the bidder cannot use turns into a no-bid without any error being raised. Typical causes are a missing required field, a deprecated value the bidder no longer reads, or consent signals a campaign needs that are absent.
Returning BidResponse.nbr instead of a bare 204 makes a low bid rate diagnosable. Code 2 (Invalid Request) points at malformed traffic, codes 3 to 5 at suspected invalid traffic, and code 8 (Unmatched User) at identity gaps. An exchange that aggregates these codes can tell a seller what to fix instead of only reporting fewer bids.
Read more
Related terms
Every term is in the glossary.