Rule reference

Proposed bid price is negative

artf.mutation.price_negativeerrorARTF mutation set

The shaded price is below zero, which no auction can settle.

What it means

adjust_bid.price is negative. Bid prices in OpenRTB are CPMs in the response's currency.

Why it matters

A shading model that subtracts an absolute amount from a low bid crosses zero, and clamping is often left out because the case looks impossible in testing. Applied, it produces a bid nothing downstream can price.

How to fix it

Clamp shaded prices at or above the applicable floor, and treat a shade that would go below it as a decision not to bid rather than as a negative price.

Example that trips it

{ "intent": "BID_SHADE", "op": "OPERATION_REPLACE", "path": "/seatbid/dsp-1/bid/bid-abc", "adjust_bid": { "price": -2.5 } }

Check your payload

Paste a bid request or response into the tester to see whether this code fires against it, or gate on the id in CI with the CLI: the id is stable, wording is not.

Back to the full diagnostic code reference.