BidRequest.imp[].banner

Banner

A display placement — static images, expandables, or in-banner video.

Fields

Field	Type	Level	Description
format	object[]	recommended	The permitted sizes for this placement.
w	integer	recommended	Exact width in device-independent pixels.
h	integer	recommended	Exact height in device-independent pixels.
pos	integer	optional	Ad position on screen.
btype	integer[]	optional	Blocked banner ad types.
battr	integer[]	optional	Blocked creative attributes.
mimes	string[]	optional	Supported content MIME types.
topframe	integer	optional	1 if in the top frame rather than an iframe.

Example

{
  "format": [
    { "w": 300, "h": 250 },
    { "w": 336, "h": 280 }
  ],
  "pos": 1,
  "topframe": 1
}

What matters in practice

Use the format array rather than a bare w and h pair. A single fixed size restricts the placement to bidders holding exactly that creative, while a format array lets the same slot accept every size that fits — the same argument as accepting several sizes on an ad server placement, expressed in the protocol. Seeing only w and h on a request usually means an older integration, and it is a reliable predictor of thin demand on that inventory.

Related objects

Field names, types and requirement levels from the IAB Tech Lab OpenRTB 2.6 specification (2.6-202211), verified 30 July 2026. The practice notes are not spec text.