What is the difference between a direct seller and a reseller in ads.txt?
In ads.txt, DIRECT means the publisher has its own account with that ad system and is paid directly, while RESELLER means an intermediary is authorized to sell the publisher's inventory through its account. Direct paths are usually shorter and cheaper. Resellers are legitimate if authorized, but they add fees and make it harder to trace where impressions come from.
A direct seller relationship means the SSP pays the publisher itself. A reseller could be a network, sales house or another SSP. Buyers often prefer direct paths during supply path optimization, and many trim resellers to reduce the ad tech tax and fraud risk.
Mislabelling is common: an entry marked DIRECT whose sellers.json record shows an intermediary is a red flag. Keeping ads.txt and sellers.json consistent is part of good supply hygiene.