Mobile app VAST ad tag setup

Last updated on June 14, 2018

Video in the OpenX Ad Exchange is in Beta release only. Please contact your Account Manager to have this feature enabled.

The following instructions are for publishers who don't use Fyber, ironSource, or MoPub and would like to configure a Video Ad Serving Template (VAST) ad tagA small piece of code that defines the ad space where ads display on a website. It includes parameters that describe the inventory advertising campaigns can target, which may in turn display ads in the ad space. for mobile appSynonymous with mobile. Refers to the use of an app via a mobile device, specifically to differentiate from mobile web. linear videoAn ad or ad unit that displays in sequence with video content in a video player. Sequencing may be pre-roll, mid-roll, or post-roll. Can be accompanied by a companion ad. An example is a video ad that plays before a video starts, though static images may also serve. ad units.

In order to complete the setup of a video ad unitThe smallest inventory component that represents the space on a site where ads display. and start serving video ads, you must configure the base VAST ad tagSynonymous with VAST URL. An HTTP-based URL that enables communication between video players and ad servers. Publishers configure these tags in order to serve video ads on their sites. generated when you create a linear video ad unit.

The screenshot below shows an example base tag, where the blurred section is a placeholder for your instance name. This base tag includes the ad unit ID (auid) and dr=1 (no redirect for cookiesSmall text files sent from a web server to a browser, then returned by the browser each time it logs on to that server. Advertisers use cookies to monitor the number of ads that have been shown to a visitor, while they are used by websites to gauge numbers of unique visitors.) already appended.

VAST ad tag

When viewing your VAST ad tag, you will see a VAST URI and XML block. OpenX provides both, but check your ad serverA complete digital advertising platform where publishers sell, manage, and deliver their advertising inventory across all digital formats. or video player's documentation to determine which you should use.

Append parameters and macros

After generating your base tag, you should append parameters and macrosFor OpenX, a command enclosed in curly braces {} that dynamically inserts attributes into your HTML or third-party ad creatives and click-through URLs when OpenX serves an ad. Other macros, like from your video player, may have alternate formatting.. Appending the required and highly recommended parameters adds an additional level of detail to your tag and ad requestCommunication from a web browser or app to an ad server to display an ad. that can inform bids from buyers.

Appending macros enables you to pass information into those parameters dynamically, ensuring that the parameters you include are as accurate as possible. You can find the relevant macros in your ad server or video player's documentation, depending on where you plan to traffic your VAST ad tag.

If you need to express your traffic in real time in a detailed way, you can augment your ad tag with our OpenRTB object query string argument. For more information, see OpenRTB supply-side ad request parameter values.

Required and highly recommended parameters

For more information on these and other parameters, see Mobile ad request parameters.


  • url
  • ifa
  • lmt
  • app.bundle
  • lt (if available)
  • lat (if available)
  • lon (if available)

Highly recommended

  • af
  • vrw (for rewarded video)
  • vht
  • vwd
  • net
  • crr
  • cb
  • ua
  • gdpr
  • gdpr_consent

Sample VAST ad tag - Fully configured with placeholders for macros

The example tag below shows a base VAST ad tag with OpenX's required and highly recommended parameters, as well as placeholders for macros. This is a rewarded video tag, so it also includes the vrw parameter.

Specific integration types (like server-to-server) and inventoryAd space available on a website or app. The basic unit of inventory for OpenX is an ad unit. types have additional parameters. You can pass in parameters for settings you chose in the OpenX Ad Exchange user interface (UI) to dynamically override them as needed.

Incorporate your tag

Add the fully configured VAST ad tag to your ad server or video player. Please contact your OpenX account manager once you've completed this step.

Next steps

Now that you have configured your VAST ad tag, you need to set up OpenX selling rules.

See also

This topic applies to Ad Exchange.