Creative Selection

After a line item passes eligibility checks, its creatives are filtered based on the impression type and dimensions.

Banner creative matching

For banner impressions, each creative's width and height must match the impression:

• If imp.banner.format is defined, the creative dimensions must match one of the format entries

• Otherwise, the creative must match imp.banner.w and imp.banner.h

Only creatives with matching dimensions are eligible.

Native creative matching

For native impressions, the creative's content field must be a JSON object with fields that satisfy the required assets in the bid request's imp.native.request.

The creative content uses a simplified JSON format:

{
  "title": "Ad Title",
  "img": "https://cdn.example.com/main.jpg",
  "icon": "https://cdn.example.com/icon.png",
  "description": "Ad description text",
  "brand": "Advertiser Name",
  "cta": "Learn More",
  "price": "$9.99",
  "clickUrl": "https://advertiser.com/landing"
}

Each field maps to an OpenRTB Native 1.2 asset type:

Creative field	Native asset type	OpenRTB type ID
title	Title	title
img	Main image	img type 3
icon	Icon image	img type 1
brand	Sponsored (advertiser name)	data type 1
description	Description	data type 2
cta	Call to action text	data type 12
price	Price	data type 6
clickUrl	Click-through URL	link.url

Eligibility: A creative is eligible if it has content for all assets marked as required: 1 in the bid request. Optional assets (required: 0) do not affect eligibility.

Response building: The DSP builds a Native 1.2 response using only the assets present in the bid request and maps each response asset ID to match the corresponding request asset ID (required by Prebid.js).

Video and audio

For video and audio impressions, all creatives of the line item are eligible regardless of dimensions.

Creative fields

Field	Type	Description
id	number	Unique creative identifier
name	string	Creative name
status	string	active or paused
isArchived	boolean	Whether the creative is archived
w	number | undefined	Width in pixels (required for banner, optional otherwise)
h	number | undefined	Height in pixels (required for banner, optional otherwise)
adomain	string	Advertiser domain (e.g. advertiser.com)
content	string	Ad markup (HTML for banners, VAST XML for video, JSON for native)
mediatype	string	banner, video, native, or audio
weight	number	Weight for creative rotation (default: 1)

Creative rotation

When multiple creatives from the same line item match an impression, they are all included as candidates. The final selection is based on bid price (see Bid Selection).

Split creatives

When a line item uses splits, each split can have its own set of creatives. If a split is eligible, only that split's creatives are used (subject to the same dimension matching rules). If no split is eligible, the line item's base creatives are used as a fallback.