1. Preview video ads by uploading a VAST tag
2. View the VAST content (XML)
3. View or download the video file

VAST, which stands for Video Ad Serving Template, is an XML schema used to tell video players how to play a video ad.
Just like HTML ad tags and HTML5 ads, VAST tags are generated by an ad server.

The VAST XML data contains details about the ad media type, how the ad should be rendered, and the ad's duration, tracking information, and pricing (if applicable).

We support all major VAST versions including:

• VAST 2.0: Basic video ad serving with linear ads
• VAST 3.0: Added non-linear ads, companion ads, and better error handling
• VAST 4.0: Latest version with improved viewability tracking and verification
• VAST 4.1: Enhanced measurement and universal ad ID support
• VAST 4.2: Advanced features for programmatic advertising

Our VAST tester automatically detects the version and validates compliance with the specific version's requirements.

To ensure VAST 4.0 compliance, our tester validates:

1. XML structure: Proper VAST 4.0 schema validation
2. Required elements: AdSystem, AdTitle, Impression tracking
3. Video formats: MP4, WebM, and other supported codecs
4. Tracking events: Start, complete, quartile tracking pixels
5. Error handling: Proper error URLs and fallback mechanisms
6. Viewability: VAST 4.0 viewability measurement support

Upload your VAST tag and we'll provide a detailed compliance report highlighting any issues that need to be addressed.

VAST tags support multiple video formats for maximum compatibility:

• MP4 (H.264): Most widely supported format across all devices
• WebM (VP8/VP9): Google's format, good for web browsers
• MOV (QuickTime): Apple format, primarily for iOS devices
• FLV (Flash Video): Legacy format, limited modern support
• HLS (HTTP Live Streaming): For adaptive bitrate streaming

We recommend providing multiple formats in your VAST tag for best compatibility. Our tester will verify that all video URLs are accessible and playable.

Common VAST tag issues and solutions:

Video file not found (404 error)

Check that all MediaFile URLs are accessible and return valid video files

Invalid XML structure

Validate your XML against the VAST schema and fix syntax errors

Missing tracking pixels

Ensure Impression and tracking event URLs are properly formatted

Unsupported video codec

Provide MP4 (H.264) format for maximum compatibility

Timeout issues

Optimize video file sizes and ensure fast server response times

Our VAST tester provides specific error messages and recommendations for each issue found in your tag.

Linear VAST ads:

• Play before, during, or after content (pre-roll, mid-roll, post-roll)
• Take full control of the video player
• Typically 15-30 seconds long
• Cannot be skipped (unless skip functionality is included)

Non-linear VAST ads:

• Overlay on top of content without interrupting playback
• Include banner overlays, pop-ups, or interactive elements
• Allow content to continue playing underneath
• Can be closed or dismissed by users

Our VAST tester supports both linear and non-linear ad formats and will validate the appropriate requirements for each type.

VAST wrapper tags are used to redirect to another VAST tag, creating a chain of ad serving:

1. Initial request: Video player requests VAST tag from ad server
2. Wrapper response: First server returns wrapper pointing to another VAST URL
3. Redirect: Player follows wrapper to final VAST tag
4. Final response: Ultimate VAST tag contains actual video creative

Wrappers are commonly used for:

• Ad network mediation and header bidding
• Adding additional tracking pixels
• Implementing frequency capping
• A/B testing different creatives

Our tester follows wrapper chains and validates each step, ensuring the final creative loads properly.