AdCP — Display Ads

Display inventory uses three canonical kinds: image, html5, and display_tag. Size, file, interaction, and slot constraints live in params; a size-specific named format ID is not needed.

Static image

{
  "format_option_id": "homepage_image_300x250",
  "format_kind": "image",
  "params": {
    "width": 300,
    "height": 250,
    "max_file_size_kb": 200,
    "image_formats": ["jpg", "png", "webp"],
    "slots": [
      { "asset_group_id": "image_main", "asset_type": "image", "required": true },
      { "asset_group_id": "landing_page_url", "asset_type": "url", "required": true }
    ]
  }
}

{
  "format_kind": "image",
  "format_option_ref": { "scope": "product", "format_option_id": "homepage_image_300x250" },
  "assets": {
    "image_main": {
      "asset_type": "image",
      "url": "https://cdn.acmeoutdoor.example/trail-pro-300x250.png",
      "width": 300,
      "height": 250,
      "alt_text": "Trail Pro boot on a mountain path"
    },
    "landing_page_url": { "asset_type": "url", "url": "https://acmeoutdoor.example/trail-pro" }
  }
}

Multi-size image

Use sizes[] when one creative contract accepts a closed set of sizes:

{
  "format_kind": "image",
  "params": {
    "sizes": [{ "w": 300, "h": 250 }, { "w": 728, "h": 90 }, { "w": 320, "h": 50 }],
    "slots": [{ "asset_group_id": "image_main", "asset_type": "image", "required": true }]
  }
}

Use min/max width and height for a genuinely responsive envelope. Exact-size, multi-size, and responsive modes are mutually exclusive.

HTML5 and third-party tags

html5 describes a buyer-supplied HTML bundle. display_tag describes externally served HTML or JavaScript markup. Keep them separate because validation, hosting, security, and measurement differ.

{
  "format_kind": "display_tag",
  "params": {
    "width": 300,
    "height": 250,
    "slots": [
      { "asset_group_id": "serving_tag", "asset_type": "html", "required": true },
      { "asset_group_id": "impression_tracker", "asset_type": "pixel_tracker", "required": false }
    ]
  }
}

Buyers discover seller acceptance from Product.format_options[]. Creative agents that can build or validate these contracts advertise matching creative.supported_formats[] entries. See Canonical formats, Creative manifests, and Universal macros.