Yahoo DSP HTML5 banner specs

Yahoo's demand-side platform, formerly BrightRoll and then Verizon Media DSP. Takes a single HTML5 ZIP with one .html at its root, caps animation at 15 seconds, and reads the click destination from a clickTag variable the ad server populates at trafficking time, so the creative must defer to a value that may already be set under any casing.

Sourced from Yahoo DSP documentation · 20 September 2026Foldwrap exports to Yahoo DSP

Also known as Yahoo, Yahoo Advertising, Verizon Media DSP, Oath, BrightRoll, BrightRoll DSP, Verizon Media DSP, BrightRoll DSP.

Check a ZIP against Yahoo DSP Export a bundle for Yahoo DSP

Yahoo DSP banner requirements

Category	DSP
Regions	GLOBAL
Maximum ZIP size	1 MB zipped
Entry file	index.html
ZIP structure	Entry file must sit at the ZIP root
Ad size meta tag	Optional
Required markup	Yahoo requires the creative to be an HTML document with an html root element.; Yahoo requires the document to contain a head element.; Yahoo requires the document to contain a body element.
External assets	External assets discouraged
External fonts	Allowed
Secure references	Every external reference must be served over HTTPS
Click method	clickTag variable
Click variable	clickTag
Click URL at export	Left empty — the platform sets it when the ad is trafficked
Multiple click destinations	One click area per banner
Maximum animation length	15s
Animation must stop	Yes, once the limit is reached
Audio	Allowed
Video	Allowed
Backup image	Required alongside the HTML5 creative

Official requirements Also from Yahoo DSP: HTML5 Guidelines, General Specifications, Additional Site Served Requirements (packaging and clickTags), 300x250 Medium Rectangle (Desktop) file-weight table.

Yahoo DSP clickTag code

This is the click declaration Foldwrap writes into an HTML5 export for Yahoo DSP, with a placeholder destination. Copy it into your own creative if you are hand-building the banner.

Yahoo DSP clickTag

window.clickTag = window.clickTag || window.clickTAG || "https://www.example.com/landing";

Yahoo DSP sets the destination at trafficking time, so an empty value in the exported file is correct and expected.

Why Yahoo DSP rejects a banner

These are the rules Foldwrap checks a package against before it is delivered to Yahoo DSP. Each is derived from the requirements above, so a constraint Yahoo DSP does not state is not checked and is not listed.

errorAnimation runs longer than allowedShorten the timeline or reduce the loop count.
errorClick is not wired for this platformDeclare clickTag in the creative and open it on click.
errorEntry HTML is not at the ZIP rootRe-zip the contents, not the containing folder.
errorExceeds size limitCompress images, subset fonts to the glyphs actually used, and drop unused assets.
errorNo entry HTMLAdd index.html at the ZIP root.
errorReferenced asset is not in the packageRe-export the creative so every referenced asset is bundled.
errorRequired markup missing
warningBackup image not included
warningElement destinations flatten hereKeep a target that supports element destinations in the set, or set a default click URL that suits every element.
warningExternal reference the platform discouragesBundle the asset inside the ZIP if you can; Yahoo DSP publishes no list of hosts it accepts.

Foldwrap runs these checks on every package it exports for Yahoo DSP, and names the creative and the constraint when one fails.

Sources

Every figure above, with the document it came from and the date we read it.

Auto-Initiated creative assets max size: 1MB
emea.adspecs.yahooinc.com · retrieved 20 September 2026
File Weight: Measured after all code and assets are stored to a .zip file
adspecs.yahooinc.com · retrieved 20 September 2026
All creative assets (images, code, etc.) should be submitted in a single .zip file. There should be only one (1) .html file at the root of the package that starts the ad.
adspecs.yahooinc.com · retrieved 20 September 2026
There should be only one (1) .html file at the root of the package that starts the ad.
adspecs.yahooinc.com · retrieved 20 September 2026
<meta> tags can be used to identify the size of the ad creative. For example: <meta name='ad.size' content='width=300, height=250'>
adspecs.yahooinc.com · retrieved 20 September 2026 · likely
Loading files from cross domains is not permitted for security reasons (except for Whitelisted Public Libraries (see Tools and Libraries below for more information
adspecs.yahooinc.com · retrieved 20 September 2026
The .zip file must include ALL assets and reference code such as JavaScript libraries. Once the .zip file is uncompressed, the ad (an .html file) must be viewable without a network connection (all code and assets used in the ad are contained in the .zip file).
adspecs.yahooinc.com · retrieved 20 September 2026
You may use web fonts, such as Adobe Web Fonts (https://edgewebfonts.adobe.com/) or Google fonts (https://www.google.com/fonts) with the following caveats
adspecs.yahooinc.com · retrieved 20 September 2026
Must be SSL compliant
adspecs.yahooinc.com · retrieved 20 September 2026
Animation length cannot exceed 15 seconds
adspecs.yahooinc.com · retrieved 20 September 2026
Autoplay animation and/or video length cannot exceed 15 seconds
adspecs.yahooinc.com · retrieved 20 September 2026
Audio must be muted on autoplay. Onload/Autoplay audio is not permitted. Sounds played on click are allowed. All sounds are subject to approval by Yahoo
adspecs.yahooinc.com · retrieved 20 September 2026
Onload/Autoplay audio is not permitted. Sounds played on click are allowed.
adspecs.yahooinc.com · retrieved 20 September 2026
Must support MP4/H.264 and WebM/VP8 playback. OGG/Theora support is optional
adspecs.yahooinc.com · retrieved 20 September 2026
Interactivity within the unit is allowed as is ad expansions and other effects that work with page content.
adspecs.yahooinc.com · retrieved 20 September 2026
For Yahoo-served executions, backup image(s) should be included in the .zip package (it will not be counted against total file weight) when submitted.
adspecs.yahooinc.com · retrieved 20 September 2026 · likely
Backup/Static Image - JPG or PNG
adspecs.yahooinc.com · retrieved 20 September 2026
Use the clickTag variable (not case sensitive) for the click event (i.e. this can be clickTag, clickTAG, clicktag). To implement a clickTAG, please use the below: <a href="javascript:window.open(window.clickTag, '_blank')">Click Here!</a>
adspecs.yahooinc.com · retrieved 20 September 2026
Multiple clickthrough URLs are NOT supported for standard ad files being uploaded directly to our DSP at this time
adspecs.yahooinc.com · retrieved 20 September 2026
Remove any code that sets clickTAG to another url
adspecs.yahooinc.com · retrieved 20 September 2026 · likely

Frequently asked

What is the maximum file size for a Yahoo DSP HTML5 banner?

Yahoo DSP accepts an HTML5 package up to 1 MB zipped. Note what the cap measures: a bundle can compress under the limit and still be refused if the figure is taken unzipped.

How do I set the clickTag for Yahoo DSP?

Declare clickTag in the creative. Yahoo DSP replaces the value when the ad is trafficked, so exporting with an empty destination is normal and correct.

Can a Yahoo DSP banner have more than one clickable link?

No. Yahoo DSP takes a single click destination for the whole banner, so every click goes to the same page regardless of which element was clicked.

Can a Yahoo DSP banner load fonts or scripts from a CDN?

Yahoo DSP asks you to avoid loading essential parts of the creative from an external host, but publishes no list of hosts it accepts and no outright ban. Bundle what you can inside the ZIP; treat anything left outside as a risk you are choosing.

Other platforms

Compare every platform side by side, or produce a Yahoo DSP-ready bundle from an approved Figma design with Foldwrap.