Back to Glossary


What is VAST Tag

Video Ad Serving Template or VAST Tags are third-party-generated ad tags that connect ad servers with video players. VAST Tags aim to enable ad servers to deliver ads seamlessly.

VAST uses an XML (Extensible Markup Language) schema to transfer important metadata about an ad to a video player from an ad server. Simply put, VAST is a language that the video player understands and speaks. It is generated in XML, a format readable by humans and machines.

A video player that understands VAST can play third-party video ads, regardless of which ad server or ad network a publisher uses.

Types of VAST Tags

VAST Tags are usually separated into two categories:

  • Server-side VAST Tags: These VAST Tags are used with a video player that runs on the ad server. The ad server receives the VAST Tag from the ad network. It then communicates with the video player on the server to render the ads. This method helps improve ad delivery time and reduce latency.
  • Client-side VAST Tags: These VAST Tags are used with a video player that runs on the client’s browser. The video player requests a video ad, and the ad server will respond with a VAST tag that contains information about the ad creative and ad duration. The client-side video player will render the ad to the user.

History of VAST Tag

In 2008, Interactive Advertising Bureau created Version 1.0 of VAST Tag. They have gone on to play an important role in the digital video marketplace.

Version 1.0 contained play, stop and pause functionalities. It also had basic linear event tracking.

Version 2.0, in addition to the features in Version 1.0 offered quartile event and player tracking.

Version 3.0 offered all of the above-mentioned features but it also offered OBA compliance, improved error reporting, and the ability to display skippable ads.

Lastly, Version 4.0, launched in 2018, offers support in many aspects. It supports many options for ads, including separate video and interactive files, mezzanine files, server stitching, advanced reporting, and closed captioning capabilities.

How does VAST Tag work

VAST Tags operate on a simple 3-step process.

  • Step-1 - VAST Request: The video player sends an ad request to the ad server to retrieve a video ad of the correct format and type.
  • Step-2 - VAST Inline Response: Once the ad server receives the request, it returns an inline response containing information like the appropriate media files and tracking URLs.
  • Step-3 - Tracking VAST URLs are sent: After the video has been played and interacted with enough times, the video player fires the tracking VAST URL and collects the impression metric of the ad to help track its performance better.

How to create a VAST Tag

Creating VAST Tags is a relatively simple process and can be done in three different ways. They are as follows.

  • Creating VAST Tags Manually: If a publisher or developer has experience working with XML, then creating a VAST Tag manually will be quite a straightforward process. They can create their VAST Tags using the <VAST/> XML tag.Please note that all VAST Tags open with <VAST version=”x”> and close with </VAST>.
  • Creating VAST Tags with Google Ad Manager: Publishers can create VAST Tags with ease using the predefined parameters in Google Ad Manager. One can create VAST Tags on this platform by following these steps.
  • Creating VAST Tags using third-party tools: Apart from Google Ad Manager, many other third-party tools can be used to create VAST Tags. Each tool differs from the other so one must familiarize themselves with the tools before making use of them. One also needs to ensure that their video player supports all the specified details and thereby, omit any possible errors while displaying ads.

Benefits of VAST Tags

VAST Tags help publishers effectively utilize their inventories and monetize their app or website effortlessly. It carries many benefits and they are as follows.

  • Easy to create and operate: VAST Tags are simple to create and make use of.One does not require any prerequisite knowledge of programming.
  • Simplified workflow: VAST Tags have streamlined the communication between ad servers and video players, enabling effective ads.
  • Standardized processes: The error processing and debugging process for VAST Tags are standard and can be performed with ease, causing a decrease in playback errors.
  • Time and money efficient: By adhering to simple VAST Tags standards, publishers can save a lot of time and money.

Related Terms

The only ad platform built for developers by developers.

Contact us now for a product that fits your needs! It’s quick, simple and easy.

footer image