${AUCTION_SEAT_ID}

What it expands to

ID of the bidder seat for whom the bid was made.

Expands in notice URLs and adm with the seat id the bid was submitted under.

What to watch for

Useful when one bidder endpoint serves many seats: without it, win notices cannot be attributed to the right buyer account.

Encoding

When a macro rides inside another URL as a query parameter, the expanded value must survive URL parsing: exchanges support suffixed forms like ${AUCTION_SEAT_ID:B64} (base64) where documented, and values containing reserved characters must be percent-encoded. An unencoded expansion is the most common reason a notice URL truncates at the first ampersand.

Related

• All substitution macros
• Where nurl, burl, and lurl fire in the delivery flow
• Loss reason codes
• ${AUCTION_ID}
• ${AUCTION_BID_ID}
• ${AUCTION_IMP_ID}
• ${AUCTION_AD_ID}
• ${AUCTION_PRICE}