An interstitial ad (or a full-screen ad) is a type of ad that mostly covers the
screen. Thus publisher contents don't appear on the screen when an interstitial
ad is shown.

You can identify an interstitial ad opportunity in the bid request by verifying
that the bid request's `BidRequest.imp.instl` field is set to `true` in
Protobuf, or `1` in JSON.

## Configure interstitial pretargeting

You can use the [Real-time Bidding API](https://developers.google.com/authorized-buyers/apis/realtimebidding/reference/rest.md.txt) to configure your pretargeting
with the [`bidders.pretargetingConfigs`](https://developers.google.com/authorized-buyers/apis/realtimebidding/reference/rest/v1/bidders.pretargetingConfigs.md.txt) resource. To
target interstitial ads, you must create a `PretargetingConfig` resource with
the `interstitialTargeting` field set to `ONLY_INTERSTITIAL_REQUESTS`. To
learn more about configuring your pretargeting configuration with the Real-time
Bidding API, see [Pretargeting configurations](https://developers.google.com/authorized-buyers/apis/guides/rtb-api/pretargeting-overview.md.txt).

The more fields you specify in the `PretargetingConfig` resource, the more
precise your targeting becomes. For example, you can target mobile interstitial
ads placed in apps by configuring a `PretargetingConfig` resource with the
following:

- The `interstitialTargeting` field is set to the `ONLY_INTERSTITIAL_REQUESTS` enum value.
- The `includedPlatforms` field contains the `PHONE` and `TABLET` enum values.
- The `includedEnvironments` field contains only the `APP` enum value.

## Learn about interstitial ad formats

You can determine an interstitial ad format based on how the bid request is
populated. The following table identifies the `BidRequest` fields that are
populated for supported interstitial ad formats:

| Format | `app` | `site` | `imp.instl` | `imp.rwdd` | `imp.ext.is_app_open` |
|---|---|---|---|---|---|
| [App interstitial ad](https://developers.google.com/authorized-buyers/rtb/interstitial-ads.md.txt#app_interstitial_ad) | Yes | No | Yes | No | No |
| [App rewarded ad](https://developers.google.com/authorized-buyers/rtb/interstitial-ads.md.txt#app_rewarded_ad) | Yes | No | Yes | Yes | No |
| [App open ad](https://developers.google.com/authorized-buyers/rtb/interstitial-ads.md.txt#app_open_ad) | Yes | No | Yes | No | Yes |
| [Web interstitial ad](https://developers.google.com/authorized-buyers/rtb/interstitial-ads.md.txt#web_interstitial_ad) | No | Yes | Yes | No | No |
| [Web rewarded ad](https://developers.google.com/authorized-buyers/rtb/interstitial-ads.md.txt#web_rewarded_ad) | No | Yes | Yes | Yes | No |

### Bid with app interstitial ads

You can bid on inventory in the app interstitial ad format to place full-page
ads that render between screens during navigation of a mobile app. To learn
more about this format, see
[How mobile app interstitials work](https://support.google.com/admanager/answer/10320506).

### Bid with app rewarded ads

You can bid on inventory in the app rewarded ad format to place full-page ads
that render when a user of a mobile app chooses to view an ad in exchange for a
reward, such as in-game currency. To learn more about this format, see
[Overview of rewarded ad units](https://support.google.com/admob/answer/7372450).

### Bid with app open ads

You can bid on inventory in the app open ad format to place full-page ads that
render in the loading screen of a mobile app. The loading screens appear when
the user opens the app, or navigates back to the app from a different app. To
learn more about this format, see
[App open ad guidance and best practices](https://support.google.com/admob/answer/9341964).

### Bid with web interstitial ads

You can bid on inventory in the web interstitial ad format to place full-page
ads that render as the user navigates and interacts with a website. To learn
more about this format, see [Traffic web interstitials](https://support.google.com/admanager/answer/9840201).

### Bid with web rewarded ads

You can bid on inventory in the web rewarded ad format to place full-page ads
that render when a user browsing a website chooses to view an ad in exchange
for a reward, such as in-game currency. To learn more about this format, see
[Traffic rewarded ads for web](https://support.google.com/admanager/answer/9116812).

## Choose an acceptable ad slot size

Ad slot size for interstitial ads indicates the area that can be used to render
creatives and depends on several factors such as specific formats and screen
dimensions.

The first width and height pair in OpenRTB's `BidRequest.imp.banner.format`,
field, represents the actual ad slot size, and the remaining pairs represent a
list of acceptable ad sizes that are within range of the slot's requirements.

Creatives aren't restricted to the recommended sizes in the bid request, but all
recommended sizes in the bid request are guaranteed to be within the acceptable
size range.

You can bid with any creative whose width and height meet the following
criteria:

- Less than or equal to the ad slot width and height
- Greater than or equal to 50% of the ad slot width
- Greater than or equal to 40% of the ad slot height

If the ad size is too big or too small, the bid response is filtered with the
rejection reason `INTERSTITIAL_SIZE_MISMATCH`.

If you don't specify the ad size in the bid response, the response is filtered
with the rejection reason `MISSING_AD_SIZE`.

## Review sample bid requests

Here are some sample bid requests for interstitial ads.

### OpenRTB Protobuf

#### Show sample

\[Serialized request\](/authorized-buyers/rtb/data/request-response/openrtb_protobuf_mobile_app_interstitial_ad_request.bin){: .download}

```
id: "wKS8UeItaMI5RAYw9Pahl0"
imp {
  id: "1"
  banner {
    w: 412
    h: 774
    pos: AD_POSITION_FULLSCREEN
    api: MRAID_1
    api: MRAID_2
    format {
      w: 412
      h: 774
    }
    format {
      w: 360
      h: 604
    }
  }
  displaymanager: "GoogleMobileAds-iOS"
  displaymanagerver: "11.13.0"
  instl: true
  tagid: "4105056997"
  bidfloor: 0.01
  bidfloorcur: "USD"
  secure: true
  exp: 14400
  clickbrowser: true
  metric {
    type: "click_through_rate"
    value: 0.3207642734050751
    vendor: "EXCHANGE"
  }
  metric {
    type: "video_completion_rate"
    value: 0.012501807883381844
    vendor: "EXCHANGE"
  }
  [com.google.doubleclick.imp] {
    billing_id: 83032532617
    publisher_settings_list_id: 2887317894027751671
    publisher_settings_list_id: 8269939443573722896
    allowed_vendor_type: 0
    allowed_vendor_type: 238
    ampad: AMP_AD_NOT_ALLOWED
    creative_enforcement_settings {
      policy_enforcement: POLICY_ENFORCEMENT_PLATFORM_POLICY
      publisher_blocks_enforcement: PUBLISHER_BLOCKS_ENFORCEMENT_APPLIES
    }
    is_app_open_ad: true
    jsver: "test-sdk_123456789"
  }
}
app {
  ver: "1.0.14"
  bundle: "com.google.testapp"
  publisher {
    id: "pub-2301631347146208"
    [com.google.doubleclick.publisher] {
      country: "AE"
    }
  }
  content {
    url: "https://www.google.com"
    language: "en"
  }
  storeurl: "https://www.google.com"
}
device {
  ua: "OMITTED"
  ip: "102.78.236.0"
  geo {
    lat: 0.0
    lon: 0.0
    country: "MAR"
    region: "MA-11"
    city: "Marrakech"
    zip: "40000"
    type: IP
    utcoffset: 0
    accuracy: 3263
    [com.google.doubleclick.geo] {
      geo_criteria_id: 9197207
    }
  }
  carrier: "72009"
  language: "fr"
  make: "Apple"
  model: "iPhone14,3"
  os: "iOS"
  osv: "26.6.1"
  connectiontype: CELL_3G
  devicetype: HIGHEND_PHONE
  ifa: "df23895d-6a56-41e9-bb8c-f19163328c19"
  hwv: "iPhone14,3"
  w: 428
  h: 926
  pxratio: 3.0
  sua {
    browsers {
      brand: "Mozilla"
      version: "5"
      version: "0"
    }
    browsers {
      brand: "AppleWebKit"
      version: "605"
      version: "1"
    }
    platform {
      brand: "iPhone"
      version: "26"
      version: "6"
    }
    mobile: true
    bitness: "64"
    model: "iPhone"
    source: USER_AGENT_STRING
  }
  [com.google.doubleclick.device] {
    atts: 3
    audioout: AUDIO_SILENT
    ifa_type: "idfa"
    scrollposx: 0
    scrollposy: 0
  }
}
user {
  id: "kxz2KP24nII51245YrV2AFtsQ72"
  [com.google.doubleclick.user] {
    session {
      duration: 137
      depth: 17
      requestssinceappopen: 17
      priorclicks: 0
    }
    idage: 12960000
  }
}
at: FIRST_PRICE
tmax: 2000
cur: "USD"
bcat: "32"
bcat: "33"
source {
  schain {
    complete: true
    nodes {
      asi: "testssp.com"
      sid: "pub-1111111111111111"
      hp: true
    }
    ver: "1.0"
  }
  [com.google.doubleclick.source] {
    omidpn: "Google"
    omidpv: "afma-sdk-i-v11.13.0"
  }
}
cattax: GOOGLE_CATEGORIES
[com.google.doubleclick.bid_request] {
  google_query_id: "ANy-zc08FK-h142dS00t819143TE021SS56r617vV09n09J3OaP354s93vIU300bzJ7e5cG2"
  fcap_scope: FREQUENCY_CAPPING_SCOPE_DEVICE
  privacy_treatments {
    allow_user_data_collection: true
  }
}
```

### OpenRTB JSON

#### Show sample

```
{
  "id": "wKS8UeItaMI5RAYw9Pahl0",
  "imp": [
    {
      "id": "1",
      "banner": {
        "w": 412,
        "h": 774,
        "pos": 7,
        "api": [
          3,
          5
        ],
        "format": [
          {
            "w": 412,
            "h": 774
          },
          {
            "w": 360,
            "h": 604
          }
        ]
      },
      "displaymanager": "GoogleMobileAds-iOS",
      "displaymanagerver": "11.13.0",
      "instl": 1,
      "tagid": "4105056997",
      "bidfloor": 0.01,
      "bidfloorcur": "USD",
      "secure": 1,
      "exp": 14400,
      "clickbrowser": 1,
      "metric": [
        {
          "type": "click_through_rate",
          "value": 0.3207642734050751,
          "vendor": "EXCHANGE"
        },
        {
          "type": "video_completion_rate",
          "value": 0.012501807883381844,
          "vendor": "EXCHANGE"
        }
      ],
      "ext": {
        "billing_id": [
          "83032532617"
        ],
        "publisher_settings_list_id": [
          "2887317894027751671",
          "8269939443573722896"
        ],
        "allowed_vendor_type": [
          0,
          238
        ],
        "ampad": 2,
        "creative_enforcement_settings": {
          "policy_enforcement": 1,
          "publisher_blocks_enforcement": 1
        },
        "is_app_open_ad": 1,
        "jsver": "test-sdk_123456789"
      }
    }
  ],
  "app": {
    "ver": "1.0.14",
    "bundle": "com.google.testapp",
    "publisher": {
      "id": "pub-2301631347146208",
      "ext": {
        "country": "AE"
      }
    },
    "content": {
      "url": "https://www.google.com",
      "language": "en"
    },
    "storeurl": "https://www.google.com"
  },
  "device": {
    "ua": "OMITTED",
    "ip": "102.78.236.0",
    "geo": {
      "lat": 0.0,
      "lon": 0.0,
      "country": "MAR",
      "region": "MA-11",
      "city": "Marrakech",
      "zip": "40000",
      "type": 2,
      "utcoffset": 0,
      "accuracy": 3263,
      "ext": {
        "geo_criteria_id": 9197207
      }
    },
    "carrier": "72009",
    "language": "fr",
    "make": "Apple",
    "model": "iPhone14,3",
    "os": "iOS",
    "osv": "26.6.1",
    "connectiontype": 5,
    "devicetype": 4,
    "ifa": "df23895d-6a56-41e9-bb8c-f19163328c19",
    "hwv": "iPhone14,3",
    "w": 428,
    "h": 926,
    "pxratio": 3.0,
    "sua": {
      "browsers": [
        {
          "brand": "Mozilla",
          "version": [
            "5",
            "0"
          ]
        },
        {
          "brand": "AppleWebKit",
          "version": [
            "605",
            "1"
          ]
        }
      ],
      "platform": {
        "brand": "iPhone",
        "version": [
          "26",
          "6"
        ]
      },
      "mobile": 1,
      "bitness": "64",
      "model": "iPhone",
      "source": 3
    },
    "ext": {
      "atts": 3,
      "audioout": 3,
      "ifa_type": "idfa",
      "scrollposx": 0,
      "scrollposy": 0
    }
  },
  "user": {
    "id": "kxz2KP24nII51245YrV2AFtsQ72",
    "ext": {
      "session": {
        "duration": 137,
        "depth": 17,
        "requestssinceappopen": 17,
        "priorclicks": 0
      },
      "idage": 12960000
    }
  },
  "at": 1,
  "tmax": 2000,
  "cur": [
    "USD"
  ],
  "bcat": [
    "32",
    "33"
  ],
  "source": {
    "schain": {
      "complete": 1,
      "nodes": [
        {
          "asi": "testssp.com",
          "sid": "pub-1111111111111111",
          "hp": 1
        }
      ],
      "ver": "1.0"
    },
    "ext": {
      "omidpn": "Google",
      "omidpv": "afma-sdk-i-v11.13.0"
    }
  },
  "cattax": 500,
  "ext": {
    "google_query_id": "ANy-zc08FK-h142dS00t819143TE021SS56r617vV09n09J3OaP354s93vIU300bzJ7e5cG2",
    "fcap_scope": 3,
    "privacy_treatments": {
      "allow_user_data_collection": 1
    }
  }
}
```

## Follow best practices

Google recommends the following best practices:

- Include formatting attributes in your HTML creative snippets to center ads
  within the ad slot. Otherwise, ads render on the top left of the ad slot.

- Respond with an interstitial ad that takes up as much space as possible
  within the ad slot. Don't fill an interstitial ad slot with a much smaller
  ad. For example, a 320x480 ad is too small for a 420x800 interstitial slot.

- Don't add any close button:

  - Our SDK automatically shows a close button (where applicable) to ensure that users can click the button.
  - MRAID `useCustomClose()` is not supported.
- Use the recommended sizes from the bid request to choose acceptable ad sizes
  for your bid response.

- Compare `BidRequest.device.w` and `BidRequest.device.h` fields to choose
  creatives with an appropriate orientation.

  - We recommend having vertical and horizontal creatives so you can bid with the appropriate orientation.

## Bid with sizeless interstitials

Sizeless interstitials (also known as responsive or fluid interstitials)
dynamically resize to take up the entire ad slot width and height. Authorized
Buyers doesn't resize creatives for you. You must supply a creative that
dynamically resizes.

You only need to submit sizeless interstitials for review once, even though they
can serve at multiple sizes. To ensure your creative isn't re-reviewed for each
individual ad slot size, we recommend the following:

### Populate `BidResponse` fields

- Use `BidResponse.seatbid.bid.ext.attribute` to declare
  `Rendering: Sizeless AdX` (attribute 105) in your bid response. Declarable
  creative attributes can be found in the
  [buyer-declarable-creative-attributes.txt](https://storage.googleapis.com/adx-rtb-dictionaries/buyer-declarable-creative-attributes.txt)
  data file.

- Populate `BidResponse.seatbid.bid.w` and `BidResponse.seatbid.bid.h` with
  the size you want the creative to render based on
  [ad size requirements](https://developers.google.com/authorized-buyers/rtb/interstitial-ads.md.txt#ad_slot_size); for example, 360x480 for a 360x480 ad
  slot. The creative might still serve at other sizes. For the deprecated
  Google RTB protocol, you would populate `BidResponse.Ad.width` and
  `BidResponse.Ad.height`.

If you add the `Rendering: Sizeless AdX` attribute to an existing creative, the creative
must be re-reviewed.

### Submit creatives for pre-approval

- When [submitting a creative for review](https://developers.google.com/authorized-buyers/apis/realtimebidding/reference/rest/v1/buyers.creatives/create.md.txt), include the `RENDERING_SIZELESS_ADX` attribute in the `declaredAttributes` field. In Real-time Bidding API, creative attributes are represented using a string enum value. To learn more about how these correspond to the numerical IDs from **buyer-declarable-creative-attributes.txt** , see the [mapping guide](https://developers.google.com/authorized-buyers/apis/guides/rtb-api/creative-enum-ids.md.txt).
- Submit the creative using a size that you expect to serve, that is, a common size for interstitial creatives. The creative can still serve at other sizes.
- Each sizeless creative only counts against your creative limit once, even if it serves at multiple sizes.

## Next steps

- [Attribute iOS installs with SKAdNetwork](https://developers.google.com/authorized-buyers/rtb/skadnetwork.md.txt): Learn how to attribute iOS app installations to advertisers using SKAdNetwork.
- [Best practices for mobile app inventory](https://developers.google.com/authorized-buyers/rtb/mobile-app-best-practices.md.txt): Learn more about best practices for interstitial ads placed in apps.