Xandr (Microsoft Advertising) HTML5 banner specs

Microsoft's demand and supply platform, formerly AppNexus and then Xandr. Serves hosted HTML5 creatives from a single ZIP and supplies the click destination as a clickTag query parameter on the ad URL, which the creative reads at runtime.

Limits unverified — this page shows only what we can citeFoldwrap exports to Xandr (Microsoft Advertising)

Also known as Xandr, Microsoft Advertising, Microsoft Invest, Microsoft Monetize, AppNexus, Invest, Monetize, AppNexus.

Check a ZIP against Xandr (Microsoft Advertising)Export a bundle for Xandr (Microsoft Advertising)

Xandr (Microsoft Advertising) banner requirements

CategoryDSP
RegionsUS, EU, GLOBAL
Entry fileindex.html
ZIP structureEntry file must sit at the ZIP root
Required markupXandr requires index.html to be a complete document including the html, head and body elements.
Click methodclickTag on the ad URL
Click variableclickTag
Click URL query parameterclickTag
Click URL at exportLeft empty — the platform sets it when the ad is trafficked
Multiple click destinationsOne click area per banner

Fields Xandr (Microsoft Advertising) does not publish, or that we have not yet read from a primary document, are left off this table rather than filled with a plausible number.

Official requirements

Xandr (Microsoft Advertising) clickTag code

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

Xandr (Microsoft Advertising) clickTag
var clickTag = (function () { var m = new RegExp('[?&]' + "clickTag" + '=([^&]*)', 'i').exec(window.location.search); return m ? decodeURIComponent(m[1]) : "https://www.example.com/landing"; })();

Xandr (Microsoft Advertising) sets the destination at trafficking time, so an empty value in the exported file is correct and expected.

Why Xandr (Microsoft Advertising) rejects a banner

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

  • 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.
  • 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
  • warningElement destinations flatten hereKeep a target that supports element destinations in the set, or set a default click URL that suits every element.

Foldwrap runs these checks on every package it exports for Xandr (Microsoft Advertising), 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.

  • The ad URL returned to a publisher's page includes a `clickTag` parameter in the query string. Ad developers who prefer not to use Xandr' `getClickTag()` convenience can access the `clickTag` parameter's value with their own Javascript. In this case, the ad does not need to load the Xandr HTML5 Library.

    learn.microsoft.com · retrieved 18 September 2026

  • The zip file must contain an **index.html** file that resides at the root of the zip file and not in a subfolder.

    learn.microsoft.com · retrieved 18 September 2026

  • The **index.html** file should be a complete and valid HTML document that includes the `<html>`, `<head>`, and `<body>` entities.

    learn.microsoft.com · retrieved 18 September 2026

Frequently asked

What is the maximum file size for a Xandr (Microsoft Advertising) HTML5 banner?
Xandr (Microsoft Advertising) does not publish a file size cap for HTML5 packages that we have been able to source. Ask your account contact for the figure that applies to your placement rather than assuming an industry default.
How do I set the clickTag for Xandr (Microsoft Advertising)?
Declare clickTag in the creative. Xandr (Microsoft Advertising) replaces the value when the ad is trafficked, so exporting with an empty destination is normal and correct.
Can a Xandr (Microsoft Advertising) banner have more than one clickable link?
No. Xandr (Microsoft Advertising) takes a single click destination for the whole banner, so every click goes to the same page regardless of which element was clicked.

Other platforms

Compare every platform side by side, or produce a Xandr (Microsoft Advertising)-ready bundle from an approved Figma design with Foldwrap.