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Server-Side Ad Insertion (SSAI) Explained
Server-side ad insertion, or SSAI, places ads directly into the video stream on the server, before it reaches the viewer. The viewer's player receives one continuous stream with the ads already inside.
How SSAI works
- The stream carries markers that say where a break starts and how long it lasts, usually SCTE-35 cues.
- When a break arrives, the SSAI service asks an ad server which ads to show, commonly using the VAST standard.
- The ads are prepared in the same format as the program and stitched into the stream.
- The viewer sees the ads and the program returns at the end of the break.
Why platforms prefer SSAI
- Smoother playback: no switching between players or buffering between program and ad.
- Works on TVs and connected devices: the player only needs to play a normal stream.
- Harder to block: ads are part of the stream, not separate requests from the page.
- Targeting: each viewer can receive a different ad in the same break.
What your stream needs
Accurate, consistent break markers are the foundation. If breaks are not marked, or markers do not match the real break, ads cannot be inserted correctly. Ad insertion itself depends on the platforms, players and ad servers you work with.
Fast Monkey products mark breaks with SCTE-35 so partners can monetize them. See how Fast Monkey Pass connects distribution to monetization.