Open Bidding

Open Bidding is Google Ad Manager's server-side bidding feature, formerly called Exchange Bidding, which lets approved third-party exchanges and SSPs bid for a publisher's impressions in the same real-time auction as Google's Ad Exchange.

Google describes it as a way to invite third-party SSPs to compete in one auction through the existing Google tag, with no extra integration on the page. Ad Manager calls the partners server to server, all at once, and handles trafficking, reporting and billing. The publisher must still have its own contract with each partner, and blocking rules do not apply to Open Bidding partners by default (Google Ad Manager Help, accessed 9 November 2026).

The UK CMA studied the terms in 2020. Google developed the feature in 2016 and opened it to publishers in April 2018. Winning bidders paid Google a fee of 5% or 10% of the winning bid, depending on inventory type, and first-party demand was not allowed. Some SSPs said they lacked visibility into the auction (CMA, Appendix M, paragraphs 451 to 455, 1 July 2020).

Example: The CMA found that Open Bidding's average timeouts in the UK were 162 ms for desktop and mobile web ads and 300 ms for most video and in-app ads. One SSP called 162 ms often too short for a single demand partner to respond (paragraph 455).

Related terms: header bidding, Prebid Server, last-look, ad exchange, timeout, waterfall.

Authoritative source: Google Ad Manager Help, "Introduction to Open Bidding" (accessed 9 November 2026).

Read the full guide: Prebid vs Open Bidding vs Amazon TAM and APS.