VAST vs VPAID: New Terms in Video Ad World Explained

Oct 27, 2020

Recent data shows that video ad spend continues to surpass all its records – Emarketer reports the US programmatic video ad spend have reached almost $30 billion in 2019 which constituted almost half of all the country’s programmatic ad spend and this year the numbers are only expected to increase. With such data, the growth of video advertising is hard not to notice. Apart from this, consumers themselves show strong support of video formats with 66% choosing video content as the most preferred way to learn about the products or services from brands. These trends open up lots of great opportunities for advertisers from most business verticals, but in order to fully leverage this potential one should first get a general understanding of the general mechanisms and basic concepts regarding the format. 

At Allroll, we believe that video marketing is one of the core pillars of the digital advertising industry, so getting a basic knowledge about the industry now is a must for every marketer, channel owner, and content creator. Hence, in this blog post, we are going to investigate how to identify VAST vs VPAID, as well as what is the difference between the two and what is their function within the video advertising ecosystem. 

What is VAST vs VPAID

In short, both VAST and VPAID are the abbreviations that stand for two different video ad serving protocols – a set of standards by which video ads are delivered. To avoid any confusion with launching and measuring video advertising campaigns, the IAB (Interactive Advertising Bureau) has created and popularized these standards among the main industry players.

Today launching any video ads campaign requires using the VAST standard. This, however, cannot prevent usage of the VPAID by any means. Moreover, to get the additional features one will be adding VPAID to the VAST advertising framework. So how exactly does it all work and what are the differences between the formats? The time to investigate is now!

What is a VAST protocol?

The abbreviation VAST stands for Video Ad Serving Template and means a simple XML script developed by the IAB to ensure video players are running ads in coordination with ad servers. This script programs video players to deliver, monetize, and measure video ads in a standardized way. In particular, the protocol’s instructions include which ad has to be played, how long should it last, where should the CTA button lead, whether the ad is skippable, etc. Such a standardization ensures fast and clear communication between different video players, ad servers, and users’ devices. 

How VAST protocol works

Before we move on to the VPAID ad protocol and its definitions, let’s have a quick look at the VAST protocol’s main principles of work. The core algorithm behind it can be described as three simple steps:

Step 1. Making a request – where the video player makes a request to an ad server for delivering a new ad.

Step 2. Getting the response – where the ad server delivers all the necessary media, as well as tracking URLs and pixels.

Step 3. Launching – where the video player triggers pixels and URLs necessary for tracking and measurements.

The versions of VAST protocol range from VAST 1.0 which is no longer supported to VAST 4.2 released in June 2019 and updated in October 2019.

How to create a VAST tag?

A typical VAST tag belongs to either VAST XML or VAST URL type. But since XML files are often preferred over URL, we’ll focus on this tag’s creation process. 

There are three ways how you can generate your custom VAST tag:

  1. To manually create a VAST tag by editing and combining all the necessary parameters into a full XML file.
  2. To generate VAST tags with the help of Google Ad Manager.
  3. To use a third-party VAST tag generator.

Each of these will result in a proper fully-functional VAST tag, but the first method will probably give you more customization and the latter two will save you more time and effort.

What are some VAST pros and cons?

Just like any other concept or standard, a VAST advertising protocol has its strong and weak sides, some of which include:

Pros: universal standard for all publishers and advertisers that helps to avoid confusions; helps to automate ad delivery, thus increasing revenues by cutting some of the expenses

Cons: cannot support all of the interactive features and lacks some insights on ad performance, as compared to more sophisticated protocols.

Now that we learned basic facts and some of the subtle details regarding VAST video ads, we can move on to exploring VPAID.

What is VPAID protocol?

VPAID is the name of another script that stands for Video Player Ad Interface Definition. This script, first of all, gives advertisers an opportunity to add rich media ads to their campaigns by sustaining an interaction between video ad units and video players, thus enabling advertisers to serve rich media ads. Besides, this script is designed to support more detailed metrics and provide insights on how exactly the users engage with their rich media and other interactive ads. Apart from it, VPAID standardized the communication with third-party video players when combined with VAST.

Some of the features enabled and tracked by the protocol include, but are not limited to:

  • switching between different parts of an ad to learn more;
  • changing the size of the video;
  • answering questions in a survey within the ad;
  • participating in a game embedded into the ad;
  • form filling as a part of campaign’s survey;
  • engaging with some of the ad’s interactive elements, etc.

How the VPAID protocol works

 Just like we did previously with VAST, let us now consider the VPAID protocol as a simple stage-by-stage video advertising delivery process: 

Stage 1. Requesting an ad server – where an ad server receives a request for an ad call from the video player;

Stage 2. Waiting for feedback – where the video player receives an ad unit, compliant with VPAID standards, as well as an XML VAST file;

Stage 3. Campaign launching and optimization – where the campaign is started and the video player is in constant communication with the ad unit to ensure timely campaign optimization;

Stage 4. Reporting and tracking – where the campaign’s performance is carefully calculated and reported by the video player and ad units to the ad servers.

As we can see, the protocol is more sophisticated as compared to VAST, but still has its limitations. Its versions include VPAID 1.0 and VPAID 2.0 with the latest dominating most of the players.

How to create a VPAID tag?

Generating VPAID creatives are somewhat similar to creating HTML5 banner ads. Here are three easy steps:

Step 1. Choose an HTML5 builder and start creating a banner ad. 

Step 2. Add <video> tag to your file and send the saved changes to your or your publisher’s video player. 

Step 3. Don’t forget to test and ensure that the ad works the way you planned it.

What are some VPAID pros and cons?

Although the protocol is quite an advanced and widely-used ad delivery standard, it also has its upsides and downsides. Here is a quick note:

Pros: provides more opportunities for interactivity and the potential increase in revenue, gives better insights on viewability and other performance metrics, increases transparency, and helps to reduce ad fraud;

Cons: potential problems with websites’ performance and user experience when using JavaScript, ad creatives fail to render from time to time.

Clearly, there are certain facts that are speaking in favor of each of the protocols. However, how can one decide which one to use and what is the main difference between VAST vs VPAID?

The difference between VAST vs VPAID

Although the two share many common features there is a list of fundamental distinctions between VAST vs VPAID. Some are more obvious, while others can require additional knowledge to notice at a first glance. The following list will help you better categorize these contrasts:

The main function. The main function of the VAST protocol is to build and sustain stable communication channel between ad servers and video players to ensure proper ad delivery. In contrast, VPAID is designed to sustain a connection between video players and the ad units to facilitate the ad delivery, as well as to provide better insights and reporting.

From the user’s perspective. Regardless of its internal mechanisms and core functions, from the perspective of the user, the VAST protocol’s main function is to ensure that video players deliver ads in coordination with ad servers. At the same time, the VPAID protocol provides an opportunity for the user to engage with an ad and complete certain actions which often leads to more engagement and higher conversions.

Acceptable formats. The core of the video advertising industry, the VAST protocol is a fundamental detail for all standard in-stream video ads formats across compliant players. VPAID in this case works more as an addition, as it is designed specifically to ensure the proper delivery of interactive video ads that are played within VAST-compliant in-stream video players.

Ways of communicating data. The VAST protocol offers a standardized way of exchanging data so that any video player could easily communicate with any ad server. On top of this, VPAID adds API integrations to allow video players to display more sophisticated video ad formats with more interaction between an ad and the user.

In particular, the VAST protocol directs information regarding which ads to play and how to do it, the CTA, ad duration, and other basic characteristics of an ad. At the same time, VPAID protocol controls features such as switches between ad tabs, changing its size, filling out the form, or even playing a game.

Technical and functional qualities. On a deeper level, VAST and VPAID also have significant technical differences, some of which include:

  • VPAID allows video players to preload an ad unit, while with VAST protocol it is restricted.
  • To get viewability info VAST tags send requests to the browser’s API and the browser responds with the necessary data. VPAID tags, in contrast, control the video player and then load a JavaScript within the browser to gather the necessary info.
  • The VAST protocol provides publishers with more control over the player, while the VPAID gives it to the buy-side.

These were the most important features to note when analysing the difference between VAST and VPAID. Although this list can be continued, it should be enough to get a basic understanding of how these two protocols work. We’ve summarized some of the aforementioned facts into this short table to better visualize the concept:

The protocol



Core function

communicates between video players and ad servers

communicates between video players and ad units

Role within ads campaign

to ensure the proper delivery of video ads

to sustain communication between users and interactive ads

Formats they support

standard in-stream video across compliant players

interactive video ads within in-stream compliant players


5 versions from VAST 1.0 to VAST 4.2

VPAID 1.0 and VPAID 2.0

Once you face the need to use these protocols for your future video advertising campaigns, these facts will help you navigate the complex industry landscape and make the best solutions for your brand’s promotion.

VPAID vs VAST: which one to choose?

While both protocols are important for delivering in-stream video ads for compliant players, each one has its strengths and weaknesses when it comes to specific cases. If the advertising campaign requires interactivity between ad units and users, then VPAID is the only possible choice, as it is designed specifically to ensure the smooth delivery of such video ads to the user. At the same time, if there’s no need for complex formats and the only need is to distribute simple in-stream videos, then the VAST protocol might be enough for such a campaign. In short, one can say that VPAID should be used as an add-on to the VAST setup when the campaign’s settings demand so. All in all, both scripts can serve as a great tool for ad buyers to increase their revenue.