VAST Testing
What is VAST & How to Test VAST Tags
Learn about VAST, how to test VAST tags, and best practices for video ad creatives. Explore our guides to ensure your video ads are compliant and error-free.
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VAST tag example by Adserver Online - A third-party ad server integration example
You are viewing a VAST example tag - Adserver Online Example
VAST tag example
Have your own VAST tags? Go to the VAST Validator and paste your VAST URL or XML content to validate and preview your video ads.
VAST Tag Examples
Explore our Ad Tag Example Gallery Library. A collection of ad tag examples with detailed descriptions, code snippets and live demos.
How Our Online VAST Tester Works
- Head over to our VAST Tester.
- Paste your VAST tag into the input field.
- Click the "Validate" button to start the validation process.
- Review the validation results and fix any issues using the provided feedback.
What is a VAST Tester?
A VAST tester is a tool that loads your VAST XML ad tag and simulates how a video player would interpret it. Instead of guessing whether your tags will deliver correctly, you can test them online and spot issues before launch.
VAST Video player - Ad Preview and Inspector
Content • Paused
Viewing VAST Example Tag: Adserver Online Example
Adserver Online ad server VAST tag example. Tests third-party ad server integration and tracking for CTV, OTT and OLV compatibilities.Ad Tag Source by
Features included in this example:
- Tracking and analytics
- Cross-device compatibility
- Multiple video formats supported
- CTV/OTT
- OLV
- VAST Inline linear ad
- Video delivery MP4
- Companion banner
- VAST version 3.0
This is an example of Adserver Online's VAST tag service. A real world implementation of a VAST video ad served through Adserver Online's platform.
It features a basic Ad made for Bounty Paper Towels including tracking capabilities, click through functionality and a companion banner. The ad is designed to be compatible across multiple devices, including desktop, mobile, and connected TV platforms. With a duration of 15 seconds, this ad provides a great place to learn the basics of VAST ad tags.
To test this example, click the Validate and test Ad button
Click here to view the example tag used.
VAST Tag Preview & Validator
Once you paste your VAST tag URL and click Validate, your VAST tag preview will appear here. Our VAST online validator instantly loads your ad response, showing a live video ad playback, media file details, and tracking events.
Video ad previews are powered by the Google IMA SDK.
Our VAST tester helps you:
- Debug and troubleshoot VAST errors
- Preview video ads in real-time
- Inspect media assets and tracking pixels
- Verify compliance with VAST standards
- How to fix common VAST errors detected during validation
By running your tags through the preview, you can be confident your video ads will deliver correctly before launching campaigns.
Looking to test Html5 ad tags?Try out the AdMeIn ad tag validator.
Test a tag nowWhat We Test For?
When you run a test in our VAST Tag Tester, we check your VAST or VMAP tag for the following common issues and best practices
to view the full VAST Tag test analysis
VAST Version
Checks if the VAST version is supported and valid.We currently support all versions of VAST: 2.0, 3.0, 4.0, 4.1, 4.2
Why we test this:
Different VAST versions introduce new elements and deprecate old ones. Testing ensures the XML structure and features align with the supported version, preventing compatibility issues with players and ad servers.
Media Files
Ensures media files are present and properly formatted.We support various media file types including MP4, WebM, and Ogg.
Why we test this:
Media files are the core of any video ad. Testing ensures the file type, codec, bitrate, and delivery method meet player compatibility standards, preventing playback errors and poor viewing experiences.
Ad Duration
Validates that the ad duration is specified and reasonable.We recommend a duration of 15–30 seconds for most ads.
Why we test this:
A defined duration helps players allocate correct playback time and manage ad pods efficiently. Missing or invalid durations can cause playback interruptions or failed ad requests.
Tracking Events
Checks for required tracking events and their correctness.We support various tracking events including start, firstQuartile, midpoint, and complete.
Why we test this:
Tracking events provide essential performance metrics such as completion rate and viewer engagement. Missing or incorrect events lead to inaccurate analytics and reporting discrepancies.
Click Tracking
Verifies click tracking URLs are present.Click tracking is essential for measuring ad engagement.
Why we test this:
Click tracking URLs record user interactions with the ad. Without proper click tracking, advertisers lose insight into engagement and campaign effectiveness, affecting billing and performance analysis.
Impression Tracking
Ensures impression tracking is implemented.Impression tracking helps monitor ad views and performance.
Why we test this:
Impression tracking confirms when an ad has been served and viewed. It’s a critical metric for verifying delivery, preventing fraud, and ensuring accurate reporting to advertisers and publishers.
Companion Ads
Checks for valid companion ads if present.Companion ads enhance user engagement alongside video ads.
Why we test this:
Companion ads extend the ad experience across formats and screens. Testing ensures they are correctly linked and formatted, avoiding display issues and maintaining creative consistency.
Ad System
Validates the AdSystem element.AdSystem identifies the ad server or system that provided the ad.
Why we test this:
The AdSystem element provides transparency about the ad’s origin and helps with troubleshooting, analytics, and attribution across ad delivery chains.
API Framework
Checks for correct API framework usage.Common API frameworks include VPAID and SIMID.
Why we test this:
The API framework defines how the creative interacts with the player. Testing ensures compatibility with supported frameworks, avoiding execution failures or blocked interactions on CTV and desktop environments.
Ad Sequence
Validates ad pod sequence numbers (for sequential ads).Ensures ad sequence numbers are unique and properly ordered.
Why we test this:
Ad sequence testing guarantees that ads play in the intended order within a pod, ensuring storytelling, pacing, and compliance with campaign delivery requirements.
Sequence Timing
Checks total duration and timing of ad pods.Ensures total ad pod duration is within acceptable limits.
Why we test this:
Proper sequence timing maintains a smooth viewing experience. Overly long or poorly timed ad pods can cause user drop-off, violate publisher limits, or fail ad insertion rules.
VMAP Version
Checks VMAP version (for VMAP tags).We currently support VMAP 1.0.
Why we test this:
VMAP defines how ad breaks are scheduled in long-form content. Testing ensures compliance with supported VMAP standards, preventing scheduling conflicts or playback errors in ad stitching systems.
Ad Breaks
Validates ad breaks in VMAP.Ensures ad breaks are properly defined and formatted.
Why we test this:
Ad breaks determine when and how ads appear during content playback. Validating them ensures correct structure, preventing missing mid-rolls or misaligned ad placements.
Ad Break Timing
Checks timing of ad breaks in VMAP.Ad breaks should be scheduled at appropriate intervals.
Why we test this:
Properly timed ad breaks maintain viewer engagement and balance monetization with user experience. Poorly spaced breaks can lead to audience frustration or reduced ad revenue.
VAST References
Ensures VMAP ad breaks reference valid VAST tags.We currently support VAST 2.0, 3.0, and 4.0+
Why we test this:
Each ad break in a VMAP should point to a valid VAST tag. Testing ensures referenced VAST URLs are accessible and well-formed, avoiding empty breaks or failed ad requests during playback.
Learning and Resources
Results example
You'll need to register or login to view Ad tag validation results. After you validate your VAST tag, you'll see a detailed breakdown of each section of your VAST XML. The results show which parts passed, which failed, and how to fix any issues found.
Passed example:
Passed results will be highlighted in green and indicate that the corresponding section of your VAST XML is correctly formatted and compliant with VAST specifications.
Failed example:
Failed results will be highlighted in red and indicate that there are issues with the corresponding section of your VAST XML that need to be addressed.
Warning or Optional example:
Warnings or optional results will be highlighted in gray or yellow and indicates that while the corresponding section of your VAST XML is not critical, it may still require attention for optimal performance or self reference.
Recommendations:
Recommendations will be highlighted in blue and provide actionable insights or suggestions to improve your VAST XML, even if there are no critical issues detected.
VAST Tag Generator
Streamline training, debugging, and QA by letting you generate and validate tags all in one place.
Drag-and-Drop VAST Builder
Our VAST Tag Generator now uses a true drag-and-drop interface, so you can visually assemble VAST tags, reorder components, and validate output in one streamlined workflow.
Learn about VAST XML and Structure
Built for learning and real QA use cases, the generator shows how each drag-and-drop change maps to the final XML, making it ideal for developers, ad-ops teams, and anyone troubleshooting VAST behavior.
Other tools for video ad testing
Looking to validate video ad creatives for compliance and performance issues? Try our Video Validator tool to ensure your video ads meet industry standards.
Video Validator Tool
The AdMeIn Video Validator tool allows you to test video ad creative's asset for compliance and performance issues, ensuring your ads meet industry standards before going live.
The Video Validator helps you identify potential issues that could affect your ad's delivery and effectiveness.
- Check video format compatibility
- Bitrate and resolution analysis
- Ensure proper encoding settings
- Plus much more
VAST Validators and references
Always review your VAST tags in multiple VAST testers to ensure compatibility. Here are some recommended options
Google IMA VAST tester and inspector
Validate VAST tags using Google's official IMA VAST tester and inspector tool.Google IMA VAST tester and inspector
IAB guides and best practices
Refer to IAB's official guides and best practices for VAST compliance.IAB guides and best practices
AdMeIn Help Center
Visit the AdMeIn Help Center for comprehensive guides and support.AdMeIn Help Center
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