Server-side ad insertion (often referred to as “ad stitching”) is the process of stitching video content and ads together on the server side level rather than on the browser level (Client Side Ad Insertion). Videos and video ads are coming from different places—videos typically come from a content delivery network (CDN) and ads from an ad server (video ads can also be served from CDNs although content CDNs and ad CDNs often differ). These are then combined on the fly when people start watching videos. With server-side ad stitching that combination of video and advertising happens on the backend.

Server-side ad insertion allows for smoother ad user experiences as users do not have to wait for players to fetch ads and render them in real time. The stitching is all done prior to the user getting the ad break/pod. In the ad stitching process ad specs are matched with content specs resulting in more consistent viewer experience as the ad quality will match the content quality.

SSAI also allows publishers to mitigate ad blocking as video content and ads are stitched together as a cohesive stream on the server side which allows them to bypass browser or device-level detection/blocking. When a browser or device-level script makes a call to the ad-decisioning system the ad blocker can identify that signal as opposed to a server-side script where the ads are already stitched into the player’s content making it impossible to distinguish an ad from content.

This is a great solution for a publisher however advertisers may have concerns with measurement being made server side and request such delivery to be distinguished in reporting.