Ad Architecture
Dynamic Ad Insertion (DAI)
Reviewed by Rishabh Jain · OTT & StreamingLast updated: 2026-06-30
Dynamic Ad Insertion (DAI) serves individually targeted ads into a video stream in real time, so different viewers see different ads in the same content or live break. It's the technology that makes streaming ads addressable rather than one-size-fits-all.
Enveu take
DAI is what turns streaming inventory into targetable, measurable ad slots — the same ad break can be personalized per viewer, which is exactly why streaming ad CPMs beat broadcast.
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Where it fits in the OTT stack
Ad Break Marker→Ad Decision (VAST)→DAI / Stitcher→Player
How it works
- Content or live stream signals an ad break (e.g. SCTE-35).
- The ad server makes a real-time decision per viewer (VAST).
- DAI inserts the chosen ad — server-side (SSAI) or client-side.
- Each viewer receives an ad targeted to them.
Key components
- Ad break markers (SCTE-35/VMAP)
- Ad decisioning via VAST/VMAP
- Server-side stitching or client SDK
- Targeting and frequency data
Performance impact
- Enables addressable, targeted ads per viewer
- Higher CPMs than untargeted inventory
- SSAI-based DAI resists ad blockers
Common issues
- Missing/incorrect ad markers
- Slow ad decisions causing slate
- Frequency capping and targeting errors
When to use it
- AVOD/FAST and live ad breaks needing targeting
Signals to monitor
- Fill rate and completion
- Ad decision latency
- Targeting accuracy
Real-world example
Making live breaks addressable
A live service ran the same ad for everyone in each break.
Challenge
- No per-viewer targeting
- Lower CPMs than addressable inventory
Action taken
- Added DAI with SCTE-35 markers and server-side stitching
- Connected VAST-based ad decisioning
Outcome
Each viewer saw a targeted ad, raising CPMs and completion in live breaks.
Frequently asked questions
What is dynamic ad insertion (DAI)?
DAI serves individually targeted ads into a video stream in real time, so different viewers see different ads in the same content or live break — making streaming ads addressable.
Is DAI the same as SSAI?
They overlap. DAI is the concept of inserting targeted ads dynamically; SSAI (server-side) and CSAI (client-side) are the delivery methods. DAI is most often implemented with SSAI for reliability.
How does DAI enable targeting?
At each ad break, an ad server makes a real-time decision (via VAST) using viewer and content signals, so the inserted ad is chosen per viewer rather than being the same for everyone.
What's the difference between DAI and SSAI?
The terms overlap heavily. SSAI describes the technical method — stitching ads into the stream server-side. DAI is the broader capability of inserting personalized ads at playback time, usually implemented with SSAI but achievable client-side too.
Does DAI work against ad blockers?
Largely yes — because the ad is stitched into the same stream as the content, there's no separate ad request for a blocker to intercept. That resilience is a main reason broadcasters adopt server-side insertion for CTV.
Build it with Enveu
Run addressable streaming ads
Enveu supports DAI with SSAI, VAST/VMAP decisioning, and full ad analytics across devices.