VPAID vs VAST: Choose the Right Video Ad Tags for Your Campaigns

Brock Munro
March 29, 2022
June 27, 2024
VPAID vs VAST: Choose the Right Video Ad Tags for Your Campaigns

With video content consumption rising, understanding the differences between the VAST and VPAID ad protocols has never been more important.

Online video traffic is set to reach 82% of all consumer internet traffic in 2022, a 9% increase since 2017.

People are increasingly picking video over both the written word and even audio content, proving to digital marketers that investing in video advertising is the way to go if they want to boost their return on ad spend (ROAS).

This is far from a new trend, with research from more than a decade ago showing that advertisers experienced a 200-300% increase in click-through rates (CTRs) if their emails contained a video.

Today, advertisers spend an estimated $92 billion per year globally on video ads. This figure is expected to grow to $120 billion in just three years, despite video production becoming more affordable by the day.

Given the advertising opportunities on offer, we’ve explored the differences between VAST and VPAID in order to help you which works best for you video ad campaigns

 Table of contents:

What Is VAST?

What Is VPAID?

What Are the Differences Between VAST and VPAID?

Pros and Cons of VAST and VPAID

VAST vs VPAID: Which Is Better for Mobile Video Ads?

A Final Word on VPAID vs VAST

What Is VAST?

VAST—an acronym for video ad serving template—is a standardized script that allows video ads to be served to various digital video players by connecting them to ad servers.

The first iteration of VAST was released in 2008 and, since then, it has seen a number of updates that have evolved the technology’s functionality with a view to improving both the publisher and user experience. It uses extensible markup language (XML), a file format used for storing and transmitting data.

VAST version 4.2, released in 2019, features server-side ad insertion (SSAI) — also known as ad stitching — which helps to avoid ad blocking, while bolstering video playback across devices.

Additionally, VAST includes support for mezzanine video files. These are raw, high-quality intermediate files that can be used to generate files with varying levels of quality specific to the device that sent the ad request. This is useful for, say, ad stitching.

How does VAST Work?

VAST facilitates communication between a video player and ad server through a common protocol. VAST tags, therefore, automate the delivery to a video player, allowing for a specific ad to run in a desired location.

This process occurs over three steps: 

  1. VAST request: The video player sends a request to the ad server to serve ads.
  2. VAST inline response: The ad server responds to the request with an inline response comprising the media/video file and key tracking URLs.

Obtaining URLs: Tracking URLs and pixels are triggered. The video player then launches them so that third parties can track and measure impressions.

How VAST Gives Publishers Control

With VAST, publishers can tell the video player to decide:

  • Which ad should play.
  • The ad’s presentation in a video.
  • The ad’s duration of play.
  • Whether viewers can skip an ad and when.
  • Which URL viewers need to be taken after engaging with the ad.

Which Version of VAST Should You Use?

Plenty has been written about the different versions of VAST since its inception in 2008. Although the Interactive Advertising Bureau (IAB) introduced VAST 4.0 in 2016, the industry was slow on the uptake to upgrade from previous versions due to a number of shortcomings in areas such as measurement.

VAST 4.0 through to VAST 4.2 sought to ameliorate these issues by offering easier workflow between partners, including functionalities such as multiple Universal AD ID nodes, Digital Audio Ad Serving Template (DAAST), and improved tracking of impressions, among others. 

Below is a breakdown of the different VAST versions since the script was introduced::  

VAST 1.0: The first version of VAST supported linear video ads in formats like MOV, MP4 and 3GP. It gave advertisers basic insights into audience engagement, and users could play, stop and pause an ad. After a number of issues were identified with this version, the IAB released VAST 1.1. However, VAST 1.0 and 1.1 are currently unsupported by the IAB and the industry at large.

VAST 2.0: As the video ad ecosystem became more complex, VAST needed an upgrade in functionality. Building on VAST 1.0’s offering, VAST 2.0 featured Flash and JavaScript support, thereby allowing publishers to choose from more formats. The technology also allows for non-linear support via overlays and companion ads. You can read more about VAST 2.0 on the IAB website (PDF download).   

VAST 3.0: Released a few months after VAST 2.0 in 2012, VAST 3.0 boasts even more functionalities than its predecessors. A central facet to this update is improved VAST error reporting, which allows ad servers to correct snags associated with ad delivery.

VAST 3.0 also supports five ad formats—linear ads, non-linear ads, skippable linear ads (new), linear ads with companions, and ad pods (new)—as well as online behavioral advertising (OBA) compliance. Read more about VAST 3.0 on the IAB website (PDF download)

VAST 4.0: Updates associated with VAST 4.0 include separation of video and interactive files, ad stitching, mezzanine file support, ready-to-serve media files, separation of competing video ads, new error codes, and advanced reporting, among others.

VAST 4.1: DAAST was merged into VAST for this version. DAAST provides a common set of specifications with regard to audio ad delivery and simplifies communication between audio-only publishers and ad servers. Other VAST 4.1 improvements include ad requests based on macros, interactive templates, and non-VPAID verification.

VAST 4.2: This is the latest version of VAST, which aims to replace VPAID for interactive video ad use. You can read more about VAST 4.0, 4.1. and 4.2 on the IAB website (PDF download).

What Is VPAID?

VPAID—which stands for video player-ad interface—is also a script that in addition to VAST’s features also allows publishers to play interactive ads during in-stream videos.

The IAB launched the interface in 2009 and updated it to version 2.0 in 2012. It can be considered as an additional layer on top of VAST and is hailed for its ability to measure ad campaigns in a more comprehensive manner with superior analytics.

This functionality is a boon for both publishers and advertisers, who can use larger data sets to streamline current and future ad campaigns.

From a marketer’s perspective, VPAID’s advanced interactivity translates to higher engagement and by extension more conversions per ad unit.

VPAID supports HTML5 and JavaScript. However, VPAID can slow down page loading time and can be limited due to compatibility issues. It is also not supported by smart TVs while some interactivity features aren’t available on mobile.

In terms of end users, VPAID allows viewers to engage with different sections of an ad, answer surveys and complete forms added to an ad, and even play simple games that are integrated into a video.

How does VPAID Work?

Similar to VAST, a VPAID tag enables video ads to be served to video players via the following request-and-response steps:

  1. Request: The video player sends a request for an ad from the ad server.
  2. Server response: The server responds to the video player’s VAST XML file together with the VPAID ad unit.
  3. Conversation: The video player and ad server communicate continuously to exchange properties for the duration of the user’s session.
  4. Tracking and monitoring: The video player and ad unit send tracked impressions and other data back to the ad server(s).

What Are the Differences Between VAST and VPAID?

Now that we’ve laid out an overview of VAST and VPAID, let’s summarize the main differences between the two scripts:

1. Functionality


  • Video players communicate with ad servers. 


  • Video player communicates with video ad units.

2. Anatomy of a Video Ad


  • Publishers can decide which ad should play.
  • They can decide on the duration of the ad.
  • They can determine if a user can skip an ad and when.
  • They can edit the URL destination. 


  • Includes overlays and tabs with different information.  
  • Users are able to zoom in and out.
  • Users can interact with various elements within the video ad, such as surveys and games.

3. Control for Publishers and Advertisers


  • Publishers can choose what the video player needs to do with an ad.


  • Marketers can track and measure ad interaction in a more comprehensive fashion.

4. Ad Format Support


  • Supports relatively simple in-stream video ad formats that are not executable.  


  • Supports rich interactive in-stream video formats that are executable.

5. Video Ad Preloads


  • VAST does not allow for a video player to preload an ad unit before it renders it. 


  • VPAID enables an ad unit to be preloaded on a video before rendering it. 

6. Reporting


  • Impressions, clicks recorded, video companion clicks, video plays, video first quartiles, video midpoints, video third quartiles, video completes, video mutes, video pauses, and video full screen.


All VAST metrics, plus:

  • Average display time, average interaction time, average time, code serves, counters, exits, interaction rate, interactive impressions, rich media clicks, rich media impressions, timers, total display time, total interaction time, total interactions, video average view time, video interaction rate, video interactions, video replays video stops, video unmutes, video view rate, and video views.

Pros and Cons of VAST and VPAID

 As with any technology, VAST and VPAID have advantages and disadvantages.

 Below are pros and cons to take note of:


  • Streamlines connection between video players and ad servers in a uniform way.
  • VAST is considered the standard in the online advertising space and is well supported.
  • Reduces costs and increases return on investment (ROI).
  • Publishers sell more video ad units.
  • Gives publishers control over ad campaigns.

 VAST Cons   

  • Previous VAST versions are generally obsolete.
  • Many publishers still haven’t adopted VAST 4.0 and beyond.  
  • Fewer interactivity options.
  • Measurement of campaigns falls short.
  • Limited quality control.
  • Does not preload video ads. 


  • Interactive functionalities such as CTA overlays, surveys, and games.
  • Higher engagement from users and better conversion.
  • Strong measurement and analysis tools.
  • High video inventory demand.
  • Programmatic ad delivery (in tandem with VAST).
  • Ad preloading on video players.


  • Can slow down web pages.
  • Affect general website performance.
  • Compatibility issues (JavaScript for mobile and Flash for desktop).
  • Video failures.
  • Unsupported by smart TVs.
  • Security concerns.

VAST vs VPAID: Which Is Better for Mobile Video Ads?

Although there are differing views on which protocol to use for mobile advertising, if advertisers and publishers value interactivity and measurability then VPAID should be the preferred option.

Nevertheless, you should keep in mind that VPAID mobile inventory can be limited due to compatibility challenges. Indeed, the Brightcove video platform has noted experiencing a 25-30% failure rate on VPAID.

The IBA is currently working on replacing VPAID with the Secure Interactive Media Interface Definition (SIMID) to deal with issues such as video latency and security by adding sandboxing from the publisher player environment.

SIMID is also designed to be compatible with mobile and OTT and the IAB expects it to replace VPAID. However, despite being in development since 2017 and having been launched in 2019, it is still not clear whether that is actually happening.

A Final Word on VPAID vs VAST

VAST and VPAID are different protocols that operate to help advertisers and publishers reach their marketing goals.

While both allow for the buying and selling of video ad inventory, VAST and VPAID protocols have their advantages and disadvantages.

While a VAST tag has fewer compatibility issues when telling video players how to run video ads, VPAID offers interactive ads and greater tracking. Given that video ad spend is on the rise, marketers need to carefully weigh the trade offs of each.

Once this step has been figured out, however, your next step is to consider which might be the best video ad network for your ad campaigns.

Publift helps digital publishers get the most out of the video ads on their websites. Publift has helped its clients realize an average 55% uplift in ad revenue since 2015, through the use of cutting-edge programmatic advertising technology paired with impartial and ethical guidance.

If you’re making more than $2,000 in monthly ad revenue, contact us today to learn more about how Publift can help increase your ad revenue and best optimize the ad space available on your website or app.

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