Latency is the time it takes for a unit of data to travel across a network connection following an instruction for its transfer – for example, the time it takes for a video ad to appear in a browser. In digital advertising, publishers will be looking to reduce latency – slow delivery could result in lost impressions and lost revenue.

Latency is impacted by connection speed and bandwidth, but programmatic ad delivery also involves further processes/issues that can affect latency such as bid requests/responses, reading cookies, different file types, and large creative files.