VPAID-ssai-incompatible

VPAID is incompatible with SSAI (server-side ad insertion)

VPAID requires a browser-based JavaScript runtime that is available at impression time. Server-side ad insertion (SSAI) stitches the ad into the video stream at the server before it reaches the player. The VPAID script has no runtime context to execute in, so the interactive layer is lost. Additionally, VPAID's shared JavaScript context is the primary reason SSAI providers refuse VPAID inventory: a malicious or buggy VPAID script could manipulate the surrounding page. SIMID was designed specifically to solve this — the creative runs in an isolated iframe and does not share the player's context.