SSAI sends a pod request 1. PBS fans out via OpenRTB; bids carry IAB categories 4. applyCategoryMapping deduplicates — one winner per industry group 5, encoded as hb_pb_cat_dur keys 6. Keys return to SSAI, which passes them as query-string keywords to the ad server 7 for fill 8. A $20 bid loses to 2×$9 that fit time and exclusion.
FIELD NOTES
- Bids with zero or multiple IAB categories rejected via seatnonbid
- OpenRTB 2.5 has no pod fields; hb_pb_cat_dur is the workaround