Ad serving in CTV is the chain of systems that takes an ad request from a video player and returns a playable ad creative. The process involves VAST tags, CDN delivery, event beacon firing, and — on premium publishers — server-side ad insertion (SSAI) that stitches the ad into the content stream before it reaches the device. Understanding this chain matters for buyers diagnosing delivery problems and for publishers configuring their ad stack.
What is VAST? How the video ad serving standard works in CTV
VAST request sequence step by step, versions 2.0 through 4.x, error code diagnosis (303, 401, 402), and India CDN delivery guidance for under-5MB creatives.
VAST vs VPAID in CTV: why VPAID doesn't work on connected TV
Why VPAID fails silently on CTV native apps, how to spot error 405 in campaign reports, and why VAST 4.x with AdVerifications is the correct replacement.
What is SSAI? Server-side ad insertion explained for CTV
How SSAI stitches ads into the content stream server-side, why it outperforms CSAI on CTV beacon reliability and ad blocking resistance, and what it means for India buyers.