VAST vs. VPAID — What They Are and How They Compare
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VAST vs. VPAID — Everything You Need to Know

VAST vs VPAID ad tags BridTV

With the latest rise in popularity of online advertising, many publishers have been turning toward it to keep their businesses relevant. However, not all digital advertising methods are born equal. One particular type stands high above the rest — video advertising. But what makes it so effective?

The answer is pretty straightforward — video is currently the most popular content format on the web. Not even traditional blogging managed to overtake it!

graph depicting the most popular content marketing formats

If you combine that overwhelming popularity of video content with the fact that 64% of consumers are more likely to purchase a product after viewing a video, the potential of video advertising becomes crystal clear. And since video ad spend is currently on the rise, it means many marketers have already noticed that and have begun investing.

If you’re interested to learn what video ad formats you can choose from, check out this article.

Since video advertising is still relatively new in the online world, publishers will be unfamiliar with many of the intricacies of the process. One of the essential terms they might come across but find unfamiliar are VAST and VPAID ad tags. These are the foundation of all video advertising, so publishers must familiarize themselves with them. That will make choosing the best ones for their needs much easier.

VAST and VPAID tags are closely related but widely different. That is why we’re going to teach you everything you need to know about them and see how they compare so that you have an easier time deciding on the right ones for your business.

Let’s jump right in!

What Is a VAST Ad Tag?

VAST (video ad serving template) is a script that facilitates coordination between an ad server and a video player. That way, the said player can roll an ad that it receives from an ad server and present it to the viewer. That applies to all types of devices — tablets, desktop, mobile, and more. 

If you want to learn more about how ad serving works, check out this article.

On top of the above, publishers have plenty of customization options with these ad tags. They can let their player know things like:

  • Which specific ad to roll.
  • How long the ad should last.
  • Whether viewers can opt to skip the ad.
  • Where the video’s CTA will take the users.

All of that gives publishers plenty of control and ways to optimize their campaigns based on the data they collected.

It’s evident from the above that VAST ad tags’ sole purpose is to make players run video ads to suit publishers’ needs. However, these tags don’t only serve ads — they can do so much more. Many publishers find VAST tags so convenient because they can also offer insight into how those ads perform. With that said, you can likely see how and why this ad tag shaped the digital advertising market of today.

How Do VAST Ad Tags Work?

graph illustrating how VAST ad tags work

Here are 3-steps that all VAST tags must go through:

  1. Send an ad call request — the video player connects to the server and asks it to send an ad.
  2. Respond to the ad call — the ad server sends a response and the tracking URLs to the player that contains the necessary media files.
  3. Trigger the URLs — the video player accesses the received URLs to permit other parties to commence tracking measuring impressions.

As you can see, VAST tags are intermediaries in communication between the server and the video player. This process would have been much more tedious, were it not for VAST.

The Evolution of VAST

During its lifetime, VAST has changed significantly. There have been various versions of it throughout the years, each bringing significant upgrades. Here is a quick overview of them:

VAST 1.0MP4, 3GP, .MOV support. 
Play/Stop/Pause functionality.Basic event tracking.
VAST 2.0Added Flash and JavaScript support.
Added quartile event and player tracking.
Support for linear, non-linear, and companion ads.
VAST 3.0Ad support expanded to five ad formats.
Added skippable ads.
Added OBA compliance.
Improved error reporting.
VAST 4.0Support for separate video, interactive video files, mezzanine files, server stitching, viewability, verification, and advanced reporting.
VAST 4.1Support for ad requests.
Added VAST interactive templates.
Support for closed captioning.
Merging of DAAST (Digital Audio Ad Serving Template) with VAST.
VAST 4.2 (Current)Minor updates.

You can download the latest VAST version from here.

Are VAST Tags All-Powerful?

Unfortunately, the answer is no. Just like everything else in life, even VAST tags have downsides. Their benefits and uses are numerous, but they also have some limitations. That is especially true when compared to their VPAID counterparts. Here’s an overview of the pros and cons of VAST ad tags:


  • They are a prevalent ad tag format in the online advertising world — not hard to find support for it.
  • They offer publishers significant control over their ad efforts — they can choose which ad to play, how to do it, the length of their ad, if the viewers will be able to skip it, etc.
  • VAST tags automate the ad delivery process and reduce expenses while increasing revenue.
  • They provide insight into ad performance and effectiveness.


  • Although VAST offers information on ad performance, it’s outshined by VPAID in this department.
  • VAST does not provide as interactive an experience as VPAID.

What Is a VPAID Ad Tag?

VPAID (video player ad interface) is a script that helps video players synchronize with ad networks. The most notable difference between VPAID and VAST is that the former allows (and incentivizes) publishers to serve rich media and interactive ads to their viewers — that is something VAST cannot do. But what do we mean by interactive ads? Well, here’s what using well-crafted VPAID ads gives your users access to:

  • Clicking on different ad sections to open additional info.
  • Expanding the size of the ad at will.
  • Filling out fields or forms integrated into the add itself.
  • Taking a survey within the ad.
  • Interacting with the elements in the ad itself or even playing a minigame.

Aside from the novelties in the interaction department, VPAID ad tags also record data on user interaction with the ads themselves. That information lets advertisers take different performance metrics into account and tweak their strategies accordingly.

How Do VPAID Ad Tags Work?

a graph illustrating how vpaid ad tags work

Similarly to the way VAST tags function, VPAID ad tags also follow several steps:

  1. Send an ad call request — this step is where the player makes an ad request from the ad server.
  2. Respond to the request — this part is when the server issues a response to the video player’s VAST XML file and the VPAID compliant ad unit.
  3. Communicate throughout — at this point, the player and the video ad unit continually exchange properties back and forth. 
  4. Track activities — finally, both the video player and the ad unit collect registered impressions and other similar data and forward it to their respective servers.

The Evolution of VPAID

VPAID is VAST’s younger brother, so it doesn’t have as long of a history. So far, two versions of VPAID have been released. Here is a short overview of both of them:

VPAID 1.0Support for rendering on desktop.
Limited functionality with Flash.
VPAID 2.0 (Current)Support for rendering on mobile devices.
Introduced autoplay on chrome for smaller players (less than 400*300).
Improved functionality by introducing HTML5 and JS compatibility.

You can download the latest VPAID version from here.

What Are the Limits of VPAID Ad Tags?

VPAID ad tags might have the edge over VAST, but they still have some limitations. Nevertheless, they are still one of the best ways for video advertisers to put their brand out there as these kinds of ads draw out the highest user engagement rates and drive the most conversions. Here’s a short list of pros and cons of VPAID ad tags:


  • The most interactive ad types out there.
  • They provide more detailed ad performance and user engagement metrics than VAST tags.
  • They have better conversion rates than VAST ad tags.


  • Their mobile inventory might be limited at times due to compatibility issues.
  • They can slow down page loading times and impact overall website performance.
  • They have a higher likelihood of errors occurring, which would make the ad fail to load.

VAST vs. VPAID — How Are They Different?

Now that we’ve covered what VAST and VPAID tags are, how they work, and their positive and negative sides, it’s time to put them against each other. As closely related as they are, VAST and VPAID have significant technological and functional differences. Here is how VAST and VPAID compare in multiple categories:

Establishes communication between the video player and the ad server.Establishes an interaction bridge between the video player and ad units.
To enable video ads to run in a player by coordinating with the ad server.To serve video ads with which you can preemptively determine how they’re going to interact with the player.
Standard forms of instream video ads.Interactive video ads within instream videos.
Uniform and independent exchange of data between the ad server and video player.API integration, enabling video players to accept more complex video ads.
Doesn’t support preloading before rendering.Supports preloading before rendering.
Signals to video players what to run and how, ad duration, CTA destination, ad skipping, etc.Allows video ads to support interactive elements like clicking buttons, expanding or shrinking, submitting a form, filling in a survey, or playing a minigame.

VAST vs. VPAID: The Verdict

So what’s the verdict? Is VAST or VPAID better? Our final answer is — it’s hard to tell.

Considering that both VAST and VPAID are getting regular updates that increase the scopes of their capabilities, it’s hard to say which one will outshine the other. They both have their pros and cons in their current state, but neither is strictly better.

VPAID is indeed more versatile, though VAST makes up for that lack of variety with how simple it is to use. While VPAID can serve more advanced ads, it will also require much more work. In the end, your choice will mostly boil down to your needs as an advertiser.

But if we had to push you toward one, we’d say that if you are looking for a stable and easily accessible way to get your online video ads to your users, VAST is probably the way to go. On the other hand, if your goals are to drive more conversions and engage your viewers and don’t mind the downsides in reliability and accessibility that VPAID brings, give it a shot.

Whatever you choose, you never know which direction video ad tech will go in the future. So both of these ad tags might become obsolete in just a few years! Only one thing is certain — VAST and VPAID are currently an excellent programmatic video advertising solution. They offer advertisers a broad perspective in their marketing campaigns, and we’re positive they’ll do the same with yours!

Until next time!