SSAI vs CSAI — Which One for Your OTT?
The ad insertion decision you need to get right before you build
The core difference
| SSAI | CSAI | |
|---|---|---|
| Where ads are inserted | Server-side, stitched into the stream | Client-side, requested by the player |
| Ad blocker resistance | High — stream appears continuous | Low — ad requests can be blocked |
| Cross-device consistency | Excellent (same stream for all devices) | Variable by device/player implementation |
| Setup complexity | Higher (requires CDN, manifest manipulation) | Lower (player SDK integration) |
| Measurement accuracy | Good (server-side tracking) | Better for player-level events |
| CTV compatibility | Strong (built for CTV) | Requires per-device implementation |
Choose SSAI if you
- Are targeting CTV devices (Roku, Fire TV, Samsung, Apple TV)
- Need consistent playback and ad quality across devices
- Want stronger protection against client-side ad blocking
- Are working with a platform that has native SSAI support (Vodlix, etc.)
Choose CSAI if you
- Are primarily web/mobile and CTV is secondary
- Want simpler initial implementation
- Rely heavily on player-side tracking and ad features (SIMID, etc.)
- Have a narrow, well-understood device scope
Questions to ask your ad tech vendors
Before choosing, get clear answers on:
- What CTV devices are supported with SSAI today?
- What ad decisioning integrations exist (Google Ad Manager, FreeWheel)?
- How are measurement signals (VAST tracking events) handled?
- What consent signal support exists (TCF 2.x, GPP)?
- How does the platform handle SCTE-35 ad markers for live streams?
The practical recommendation
For most new OTT launches in 2025+: start with SSAI if your platform supports it and CTV is in scope. The operational overhead is front-loaded; the long-term playback quality and ad experience is worth it.
If you are launching web/mobile first and adding CTV later, you may start with CSAI and migrate — but plan that migration early.
Making the SSAI/CSAI decision?
Book a monetization call.