Explainer
After SSAI: why the industry is talking about server-guided ad insertion
Streaming ad delivery has spent a decade oscillating between two imperfect architectures. Client-side insertion (CSAI) lets the app fetch its own ads — great for measurement and interactivity, bad for reliability, with buffering wheels, volume jumps, and vulnerability to blocking. Server-side insertion (SSAI) stitches ads into the stream before it reaches the device — broadcast-smooth and essentially unblockable, which is why it became the default for FAST channels and live sports (see our SSAI explainer).
SSAI's cost is visibility. When the server does everything, the ad ecosystem loses the device-level signals it prices against: viewability confirmation, interactivity, precise tracking. The industry's verification and measurement stack was built for clients, not proxies — a persistent friction ppc.land's overview of the space documents well.
Enter server-guided ad insertion (SGAI): the server still owns the break — deciding when it happens and what fills it — but hands the client instructions so the device fetches and reports the ads itself. The mechanics lean on modern HLS features (notably Apple's interstitials) that let a stream delegate ad playback to the player without breaking seamlessness. The pitch: SSAI's polish, CSAI's signals.
Per ppc.land's reporting, SGAI is the direction most new 2026 CTV implementations are heading, though nobody expects a clean switchover — platforms run mixed insertion strategies per surface, and the long tail of older devices guarantees SSAI's relevance for years. The safe prediction: "how do you insert ads?" stops having one answer and becomes a per-stream engineering decision.