Ad - Waterfalling (daisy chain or waterfall tags)


Waterfalling is a mediation technique. A publisher sell ads by making sequential price offers to ad networks for an inventory, and chooses the winner in that order.

Waterfal is also known as:

  • fallback
  • client-side mediation
  • waterfall tags

Several ad networks are called one after another in order to:


An ad server software will implement it.

If the first network doesn't have any ads to serve, a call to a second network is made etc …

ie If the first party in the priority sequence did not purchase the impression, it would cascade down to the next party and to the next, until someone bought it.

where the orders are served in the following order:


The waterfall is problematic for buyers and sellers.

  • Publishers don’t know when they’re leaving money on the table.
  • Advertisers may not get a fair shot at the inventory, resulting in skewed average historical prices.

The inefficiencies of the waterfall can be solved through bidding

Documentation / Reference

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