OpenRTB

OpenRTB (Open Real-Time Bidding) is an open standard protocol developed by the IAB Tech Lab that defines how programmatic ad auctions work between supply-side platforms (SSPs) and demand-side platforms (DSPs). An OpenRTB auction works like this: when an impression opportunity occurs, the SSP sends a bid request to multiple DSPs simultaneously; DSPs respond with their maximum bid within the response time window (typically 50–100ms); the SSP selects the highest eligible bid and returns the winning creative. MailAdx supports OpenRTB integration, allowing publishers to connect to any OpenRTB-compatible demand source. For email newsletters, MailAdx adapts the standard protocol to handle open-time serving constraints (latency, email client behavior, Gmail proxy).