AdCP — Display Ads

This guide covers how AdCP represents display advertising formats, from static image banners to third-party tags and HTML5 creatives.

Display Format Characteristics

Display formats in AdCP include:

Hosted Images - Static image files (JPG, PNG, WebP, GIF)
HTML5 Creatives - Multi-asset interactive banners
Third-Party Tags - JavaScript or HTML tags served by external ad servers
Responsive Formats - Adapt to multiple sizes
Rich Media - Expandable and interactive formats

Standard IAB Display Formats

Medium Rectangle (300x250)

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_300x250"
  },
  "type": "display",
  "renders": [
    {
      "role": "primary",
      "dimensions": {
        "width": 300,
        "height": 250,
        "responsive": { "width": false, "height": false }
      }
    }
  ],
  "assets": [
    {
      "item_type": "individual",
      "asset_id": "banner_image",
      "asset_type": "image",
      "asset_role": "hero_image",
      "required": true,
      "requirements": {
        "min_width": 300,
        "max_width": 300,
        "min_height": 250,
        "max_height": 250,
        "formats": ["jpg", "png", "webp", "gif"],
        "max_file_size_kb": 200,
        "animation_allowed": true,
        "max_animation_duration_ms": 15000
      }
    }
  ]
}

Leaderboard (728x90)

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_728x90"
  },
  "type": "display",
  "assets": [
    {
      "asset_id": "banner_image",
      "asset_type": "image",
      "asset_role": "hero_image",
      "required": true,
      "requirements": {
        "width": 728,
        "height": 90,
        "file_types": ["jpg", "png", "webp"],
        "max_file_size_kb": 150
      }
    }
  ]
}

Wide Skyscraper (160x600)

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_160x600"
  },
  "type": "display",
  "assets": [
    {
      "asset_id": "banner_image",
      "asset_type": "image",
      "asset_role": "hero_image",
      "required": true,
      "requirements": {
        "width": 160,
        "height": 600,
        "file_types": ["jpg", "png", "webp"],
        "max_file_size_kb": 150
      }
    }
  ]
}

Billboard (970x250)

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_970x250"
  },
  "type": "display",
  "assets": [
    {
      "asset_id": "banner_image",
      "asset_type": "image",
      "asset_role": "hero_image",
      "required": true,
      "requirements": {
        "width": 970,
        "height": 250,
        "file_types": ["jpg", "png", "webp"],
        "max_file_size_kb": 300
      }
    }
  ]
}

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "mobile_banner_320x50"
  },
  "type": "display",
  "assets": [
    {
      "asset_id": "banner_image",
      "asset_type": "image",
      "asset_role": "hero_image",
      "required": true,
      "requirements": {
        "width": 320,
        "height": 50,
        "file_types": ["jpg", "png", "webp"],
        "max_file_size_kb": 150
      }
    }
  ]
}

Mobile Interstitial (320x480)

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "mobile_interstitial_320x480"
  },
  "type": "display",
  "assets": [
    {
      "asset_id": "banner_image",
      "asset_type": "image",
      "asset_role": "hero_image",
      "required": true,
      "requirements": {
        "width": 320,
        "height": 480,
        "file_types": ["jpg", "png", "webp"],
        "max_file_size_kb": 300
      }
    }
  ]
}

Creative Manifests

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_300x250"
  },
  "assets": {
    "banner_image": {
      "asset_type": "image",
      "url": "https://cdn.brand.com/banner_300x250.jpg",
      "width": 300,
      "height": 250
    },
    "landing_url": {
      "asset_type": "url",
      "url_type": "clickthrough",
      "url": "https://brand.com/spring?campaign={MEDIA_BUY_ID}"
    },
    "impression_tracker": {
      "asset_type": "url",
      "url_type": "tracker",
      "url": "https://track.brand.com/imp?buy={MEDIA_BUY_ID}&cb={CACHEBUSTER}"
    }
  }
}

Animated GIF Manifest

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_300x250"
  },
  "assets": {
    "banner_image": {
      "asset_type": "image",
      "url": "https://cdn.brand.com/animated_300x250.gif",
      "width": 300,
      "height": 250,
      "animated": true,
      "animation_duration_ms": 15000
    },
    "landing_url": {
      "asset_type": "url",
      "url_type": "clickthrough",
      "url": "https://brand.com/spring"
    }
  }
}

HTML Display Formats with Execution Context

HTML display creatives run as executable code, not static media. Different publisher environments have different execution constraints - some allow full DOM access, others run in SafeFrame containers with restricted JavaScript capabilities. AdCP defines explicit HTML asset requirements that specify the execution environment the HTML must be compatible with:

sandbox: Execution environment (none, iframe, safeframe, fencedframe)
external_resources_allowed: Whether the creative can load external scripts, images, or fonts
allowed_external_domains: Permitted domains for external resources (when allowed)
max_file_size_kb: Maximum file size for the HTML asset

SafeFrame is an IAB standard that provides secure isolation between ad creatives and publisher pages. SafeFrame-compatible creatives cannot use document.write(), must use SafeFrame expansion APIs, and cannot make arbitrary cross-origin requests.

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_300x250_html_safeframe"
  },
  "name": "SafeFrame HTML Banner 300x250",
  "type": "display",
  "renders": [
    {
      "role": "primary",
      "dimensions": {
        "width": 300,
        "height": 250,
        "responsive": { "width": false, "height": false }
      }
    }
  ],
  "assets": [
    {
      "item_type": "individual",
      "asset_id": "banner_html",
      "asset_type": "html",
      "asset_role": "creative",
      "required": true,
      "requirements": {
        "max_file_size_kb": 150,
        "sandbox": "safeframe",
        "external_resources_allowed": false
      }
    },
    {
      "item_type": "individual",
      "asset_id": "landing_url",
      "asset_type": "url",
      "asset_role": "clickthrough",
      "required": true,
      "requirements": {
        "protocols": ["https"]
      }
    }
  ]
}

Some publishers allow full DOM access for trusted creatives. These formats can use standard JavaScript APIs and load external resources.

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_300x250_html_native"
  },
  "name": "Native HTML Banner 300x250",
  "type": "display",
  "renders": [
    {
      "role": "primary",
      "dimensions": {
        "width": 300,
        "height": 250,
        "responsive": { "width": false, "height": false }
      }
    }
  ],
  "assets": [
    {
      "item_type": "individual",
      "asset_id": "banner_html",
      "asset_type": "html",
      "asset_role": "creative",
      "required": true,
      "requirements": {
        "max_file_size_kb": 200,
        "sandbox": "none",
        "external_resources_allowed": true,
        "allowed_external_domains": ["cdn.brand.com", "fonts.googleapis.com"]
      }
    },
    {
      "item_type": "individual",
      "asset_id": "landing_url",
      "asset_type": "url",
      "asset_role": "clickthrough",
      "required": true,
      "requirements": {
        "protocols": ["https"]
      }
    }
  ]
}

Chrome’s Privacy Sandbox introduces Fenced Frames for privacy-preserving ad rendering. These have the most restrictive execution environment.

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_300x250_html_fencedframe"
  },
  "name": "Fenced Frame HTML Banner 300x250",
  "type": "display",
  "renders": [
    {
      "role": "primary",
      "dimensions": {
        "width": 300,
        "height": 250,
        "responsive": { "width": false, "height": false }
      }
    }
  ],
  "assets": [
    {
      "item_type": "individual",
      "asset_id": "banner_html",
      "asset_type": "html",
      "asset_role": "creative",
      "required": true,
      "requirements": {
        "max_file_size_kb": 100,
        "sandbox": "fencedframe",
        "external_resources_allowed": false
      }
    }
  ]
}

Third-Party Tag Formats

JavaScript Tag Format

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_300x250_3p"
  },
  "type": "display",
  "renders": [
    {
      "role": "primary",
      "dimensions": {
        "width": 300,
        "height": 250,
        "responsive": { "width": false, "height": false }
      }
    }
  ],
  "assets": [
    {
      "item_type": "individual",
      "asset_id": "tag",
      "asset_type": "javascript",
      "asset_role": "third_party_tag",
      "required": true,
      "requirements": {
        "max_file_size_kb": 200,
        "external_resources_allowed": true,
        "strict_mode_required": false
      }
    }
  ]
}

JavaScript tag manifest:

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_300x250_3p"
  },
  "assets": {
    "tag": {
      "asset_type": "javascript",
      "content": "<script src=\"https://ad-server.brand.com/serve?campaign={MEDIA_BUY_ID}&size=300x250&cb={CACHEBUSTER}\"></script>"
    }
  }
}

HTML Tag Format

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_728x90_html"
  },
  "type": "display",
  "renders": [
    {
      "role": "primary",
      "dimensions": {
        "width": 728,
        "height": 90,
        "responsive": { "width": false, "height": false }
      }
    }
  ],
  "assets": [
    {
      "item_type": "individual",
      "asset_id": "tag",
      "asset_type": "html",
      "asset_role": "third_party_tag",
      "required": true,
      "requirements": {
        "max_file_size_kb": 200,
        "sandbox": "iframe",
        "external_resources_allowed": true
      }
    }
  ]
}

HTML tag manifest:

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_728x90_html"
  },
  "assets": {
    "tag": {
      "asset_type": "html",
      "content": "<iframe src=\"https://ad-server.brand.com/render?campaign={MEDIA_BUY_ID}&size=728x90&cb={CACHEBUSTER}\" width=\"728\" height=\"90\" frameborder=\"0\" scrolling=\"no\"></iframe>"
    }
  }
}

HTML5 Multi-Asset Formats

HTML5 formats specify multiple assets that the publisher’s ad server assembles into an interactive creative.

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_300x250_html5"
  },
  "type": "display",
  "assets": [
    {
      "asset_id": "background_image",
      "asset_type": "image",
      "asset_role": "background",
      "required": true,
      "requirements": {
        "width": 300,
        "height": 250,
        "file_types": ["jpg", "png"]
      }
    },
    {
      "asset_id": "logo",
      "asset_type": "image",
      "asset_role": "logo",
      "required": true,
      "requirements": {
        "max_width": 100,
        "max_height": 50,
        "file_types": ["png", "svg"]
      }
    },
    {
      "asset_id": "headline",
      "asset_type": "text",
      "asset_role": "headline",
      "required": true,
      "requirements": {
        "max_length": 25
      }
    },
    {
      "asset_id": "cta_text",
      "asset_type": "text",
      "asset_role": "call_to_action",
      "required": true,
      "requirements": {
        "max_length": 15
      }
    }
  ]
}

HTML5 manifest:

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_300x250_html5"
  },
  "assets": {
    "background_image": {
      "asset_type": "image",
      "url": "https://cdn.brand.com/bg.jpg",
      "width": 300,
      "height": 250
    },
    "logo": {
      "asset_type": "image",
      "url": "https://cdn.brand.com/logo.png",
      "width": 80,
      "height": 40
    },
    "headline": {
      "asset_type": "text",
      "content": "Spring Sale - 50% Off"
    },
    "cta_text": {
      "asset_type": "text",
      "content": "Shop Now"
    },
    "landing_url": {
      "asset_type": "url",
      "url_type": "clickthrough",
      "url": "https://brand.com/spring"
    }
  }
}

Responsive Display Formats

Responsive formats adapt to multiple sizes based on placement context.

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_responsive"
  },
  "type": "display",
  "responsive": true,
  "supported_sizes": ["300x250", "728x90", "320x50"],
  "assets": [
    {
      "asset_id": "background_image",
      "asset_type": "image",
      "asset_role": "background",
      "required": true,
      "requirements": {
        "min_width": 728,
        "min_height": 250,
        "responsive": true,
        "file_types": ["jpg", "png", "webp"]
      }
    },
    {
      "asset_id": "logo",
      "asset_type": "image",
      "asset_role": "logo",
      "required": true
    },
    {
      "asset_id": "headline",
      "asset_type": "text",
      "asset_role": "headline",
      "required": true,
      "requirements": {
        "max_length": 30
      }
    }
  ]
}

Rich Media Formats

{
  "format_id": {
    "agent_url": "https://creative.adcontextprotocol.org",
    "id": "display_970x250_expandable"
  },
  "type": "display",
  "expandable": true,
  "collapsed_size": "970x250",
  "expanded_size": "970x600",
  "assets": [
    {
      "asset_id": "collapsed_creative",
      "asset_type": "html",
      "asset_role": "collapsed_state",
      "required": true,
      "requirements": {
        "width": 970,
        "height": 250,
        "max_file_size_kb": 200
      }
    },
    {
      "asset_id": "expanded_creative",
      "asset_type": "html",
      "asset_role": "expanded_state",
      "required": true,
      "requirements": {
        "width": 970,
        "height": 600,
        "max_file_size_kb": 500
      }
    }
  ]
}

Display-Specific Macros

In addition to universal macros, display formats support:

Placement Context

{PLACEMENT_ID} - IAB Global Placement ID
{FOLD_POSITION} - above_fold, below_fold
{AD_WIDTH} / {AD_HEIGHT} - Ad slot dimensions in pixels

Web Context

{DOMAIN} - Publisher domain (e.g., “nytimes.com”)
{PAGE_URL} - Full page URL (URL-encoded)
{REFERRER} - HTTP referrer URL
{KEYWORDS} - Page keywords (comma-separated)

Device Context

{DEVICE_TYPE} - mobile, tablet, desktop
{OS} - iOS, Android, Windows, macOS
{USER_AGENT} - Full user agent string

Example with display macros:

https://track.brand.com/imp?
  buy={MEDIA_BUY_ID}&
  placement={PLACEMENT_ID}&
  domain={DOMAIN}&
  fold={FOLD_POSITION}&
  device={DEVICE_TYPE}&
  cb={CACHEBUSTER}

Common File Specifications

Image Requirements

File types: JPG, PNG, WebP, GIF
Max file sizes:
- Standard banners: 150-200KB
- Large formats (970x250): 300KB
- Animated GIFs: 500KB
- HTML5 initial load: 200KB

Third-Party Tag Requirements

HTTPS required: All tag URLs must use secure protocol
Max file size: 200KB for tag content
Async loading: Tags should not block page rendering

Animation Specifications

For animated GIF formats:

animated: true
animation_duration_ms: Duration in milliseconds
Common durations: 15000ms (15 seconds)

Universal Macros - Complete macro reference
Creative Manifests - Manifest structure and validation
Asset Types - Image, HTML, and JavaScript asset specifications

Documentation

Display Ads

Display Format Characteristics

Standard IAB Display Formats

Medium Rectangle (300x250)

Leaderboard (728x90)

Wide Skyscraper (160x600)

Billboard (970x250)

Mobile Banner (320x50)

Mobile Interstitial (320x480)

Creative Manifests

Simple Image Banner Manifest

Animated GIF Manifest

HTML Display Formats with Execution Context

SafeFrame-Compatible HTML Banner

Native DOM HTML Banner

Fenced Frame HTML Banner (Privacy Sandbox)

Third-Party Tag Formats

JavaScript Tag Format

HTML Tag Format

HTML5 Multi-Asset Formats

HTML5 Banner Format

Responsive Display Formats

Responsive Banner Format

Rich Media Formats

Expandable Banner Format

Display-Specific Macros

Placement Context

Web Context

Device Context

Common File Specifications

Image Requirements

Third-Party Tag Requirements

Animation Specifications

Documentation

​Display Format Characteristics

​Standard IAB Display Formats

​Medium Rectangle (300x250)

​Leaderboard (728x90)

​Wide Skyscraper (160x600)

​Billboard (970x250)

​Mobile Banner (320x50)

​Mobile Interstitial (320x480)

​Creative Manifests

​Simple Image Banner Manifest

​Animated GIF Manifest

​HTML Display Formats with Execution Context

​SafeFrame-Compatible HTML Banner

​Native DOM HTML Banner

​Fenced Frame HTML Banner (Privacy Sandbox)

​Third-Party Tag Formats

​JavaScript Tag Format

​HTML Tag Format

​HTML5 Multi-Asset Formats

​HTML5 Banner Format

​Responsive Display Formats

​Responsive Banner Format

​Rich Media Formats

​Expandable Banner Format

​Display-Specific Macros

​Placement Context

​Web Context

​Device Context

​Common File Specifications

​Image Requirements

​Third-Party Tag Requirements

​Animation Specifications

​Related Documentation

Display Format Characteristics

Standard IAB Display Formats

Medium Rectangle (300x250)

Leaderboard (728x90)

Wide Skyscraper (160x600)

Billboard (970x250)

Mobile Banner (320x50)

Mobile Interstitial (320x480)

Creative Manifests

Simple Image Banner Manifest

Animated GIF Manifest

HTML Display Formats with Execution Context

SafeFrame-Compatible HTML Banner

Native DOM HTML Banner

Fenced Frame HTML Banner (Privacy Sandbox)

Third-Party Tag Formats

JavaScript Tag Format

HTML Tag Format

HTML5 Multi-Asset Formats

HTML5 Banner Format

Responsive Display Formats

Responsive Banner Format

Rich Media Formats

Expandable Banner Format

Display-Specific Macros

Placement Context

Web Context

Device Context

Common File Specifications

Image Requirements

Third-Party Tag Requirements

Animation Specifications

Related Documentation