Ad Specifications

The DSP accepts almost any ad format that is accepted by our exchange partners. Precise specifications vary from exchange to exchange. To ensure that your ads are accepted on all inventory sources, please follow the IAB Display & Mobile Advertising Creative Format Guidelines (PDF).

The following specifications are particularly important for the widest acceptance of ads.

Display (Banner) Ads

Image dimensions (Desktop)

728x90*, 300x250*, 160x600* (standard sizes)
120x600, 300x600

Image dimensions (Mobile)

320x50*, 300x50* (smartphone banner, most common)
320x480*, 480x320 (smartphone interstitial)
300x250* (mobile interstitial, tablet in-app, mobile web)
728x90* (tablet only) 
1024x768*, 768x1024 (tablet interstitial)

File size

1024 KB (1 MB) max for individual image ad files

25 MB max for ZIP files used to bulk upload image ads

File type


Animation length

No more than 15 seconds and/or 3 loops 


Creative must clearly separated from the site content, either by a clear border or a non-white background color.

*Recommended Ad Sizes

Other Supported Ad Sizes

(availability may vary, consult RTB Inventory to verify)

120x20, 168x28, 180x150, 216x36, 234x60, 250x360, 300x50, 300x170, 300x340, 300x1050, 320x240, 320x320, 336x280, 386x300, 400x300, 468x60, 480x360, 480x800, 600x400, 631x385, 640x480, 700x450, 720x480, 750x200, 800x1200, 900x600, 970x90, 970x250, 980x120, 980x150, 990x200, 1920x480

Audio Ads

File Types

  • MP3 (.mp3)

  • Ogg Vorbis (.ogg)

  • AAC in an MPEG-4 container (File names could end in .m4a, .mp4, .aac)

Some AAC files aren’t in AAC format when within an MPEG-4 container.

Length No technical requirement for audio file length. There may be very few inventory opportunities for long audio files (over 60 seconds).

Maximum File Size

100 MB

For Basis DSP-hosted ads, Basis DSP will automatically transcode the audio into all necessary formats. If you're uploading audio files, you only need to upload a single audio file. Upload a high-quality version, and the system automatically creates copies for each type of player.

Video Ads

There are important details to consider when you want to format video files for Connected TV. See Video Ads on Premium Connected TV Inventory to ensure that your ads meet the requirements.

Ad Sizes

Minimum height of 144px, up to 2048x1080 maximum.

Note: We recommend uploading videos that are 1920x1080 for 16:9 content and 1440x1080 for 4:3 content.

Avoid uploading videos that are ultra-high definition (UHD), 4K, or higher in resolution.

Aspect Ratios 16:9 or 4:3

File Types

Refer to Brightcode Zencoder's Supported Formats and Codecs.

Maximum File Size

100 MB

Maximum Length

60 seconds (for videos uploaded to the DSP directly).

If you are using a VAST tag or have your own ad server, we have inventory for videos up to 90 seconds.

Note: Videos with an odd length fit in to the nearest 30- or 60-second time slot. For example, a 25-second video plays in a 30-second slot. A 35-second video plays in a 60-second slot. This does not impact the actual runtime of the video: a 25-second video still only plays for 25 seconds.

Other Progressive (not interlaced) format

Important Notes

  • Upload only a single size for each video. The DSP automatically creates copies for each size used by your ads. See Uploading Videos for details.
  • Ensure that your video files include audio. If your video file does not have any audio, you will not be able to upload it.
  • Upload the highest quality version of your video file. For ads hosted on Basis, the DSP automatically transcodes the video into all necessary formats. See Transcoding Videos Using HandBbrake if your original file is too large to upload.
  • See Video Ads on Premium Connected TV Inventory for important information about formatting video ads for Connected TV.


Third-party VAST 2.0 or 3.0 is also accepted. Only InLine Linear ads are accepted; non-linear and wrappers are not accepted.

Note: While third-party VAST is supported, we recommended you host audio on the Basis DSP. Third-party VAST cannot track companion impressions and clicks (a limitation of the VAST spec), and our transcoding covers the complexity of varying spec requirements for different publishers.

VAST from a third party server must contain at least one MP4 media file, but it is strongly advised that the following be in the VAST:

  • MP4 high bitrate
  • MP4 low bitrate
  • FLV high bitrate
  • FLV low bitrate
  • (Optionally, but preferably) WebM high bitrate
  • (Optionally, but preferably) WebM low bitrate

"Low bitrate" is around 400-600 kbps, "High bitrate" is around 1000-1200 kbps.

Multiple bitrates are recommended for broadest acceptance, with at least one version with a bitrate less than 400 kbps for mobile compatibility.

Ideally, the low bitrate versions are encoded at a lower resolution (i.e. 640x360 for 16:9 video, 640x480 for 4:3 video) if the high bitrate version is at a higher resolution. This is because the quality of a high-resolution video at low bitrate will be poor, and some devices, especially mobile, may have difficulty playing very high resolution (i.e. 1080p) video.

For more information, see Chapter 2 of the IAB Digital Video Format Guidelines.

Native Ads

These specifications represent native ads that can spend on almost all supply sources. To achieve optimal results, provide multiple ads that meet the characteristics of specific exchanges and publishers. However, if you only have one ad or set of ads, follow these specifications:


20 characters (however, 25 characters is accepted on almost all inventory)


90 characters

Main Image

Exactly 1200x627 (1.91:1 aspect ratio)

Max File Size 200 KB


Exactly 240x240 (1:1 aspect ratio)

Brand Name

25 characters

Note: These specs are the lowest common denominator usable on the DSP's current supply sources. Native ads vary greatly by publisher and exchange; for best results, produce ads to the specifications of each publisher or exchange.


You can upload an HTML5 directly to the DSP or use an ad tag if the ad is hosted on another server. HTML5 files must meet the IAB standards for HTML5, which are defined in HTML5 for Digital Advertising v2.0.

HTML5 ads that you upload must also meet these requirements:

  • It must be a ZIP file (*.zip). Compress all of the code required for the creative into a single ZIP file.
  • The maximum file size is 200 KB.
  • The primary HTML file must be in the root directory of the ZIP. If there are multiple HTML files, the primary file must be named "index.html".
  • The clickable area of the creative must be a single area that covers the entire creative or designated with a click tag query string parameter.
  • The creative code cannot interact directly with the parent window.

Review the following pages to learn more about setting up your HTML5 creatives: