HTML5 banner ad specs by platform

File size caps, clickTag conventions, animation limits and external-asset rules for 20 ad platforms — each figure paraphrased from the platform's own documentation and dated. 18 of 20 records have had every constraint sourced from a primary document; the rest show only what we can cite and stay silent on the rest.

Check your banner ZIP freeExport banners that pass these checks
HTML5 banner requirements by ad platform. An em dash means the platform has not published that figure, or we have not yet sourced it.
FilesClickElement linksAnimationExternal assets
AdformAd server300 KB unzipped—clickTag variableclickTAGSupported30sExternal assets allowed20 September 2026
AdRollNetwork150 KB zipped—clickTag variableclickTagOne per banner30sEverything must be in the ZIP20 September 2026
Amazon DSPDSP200 KB zipped—vendor click APIOne per banner15sApproved hosts only22 September 2026
BasisDSP1 MB zipped—clickTag on the ad URLclickTagOne per banner15s—23 September 2026
Campaign Manager 360Ad server10 MB zipped100clickTag variableclickTagSupported—External assets allowed21 September 2026
ChoozleDSP10 MB zipped100clickTag on the ad URLclickTAGOne per banner——24 September 2026
Display & Video 360DSPNo stated cap100clickTag variableclickTagOne per banner30sExternal assets allowed21 September 2026
Equativ (Smart AdServer)Ad server50 MB zipped—clickTag variableclickTagOne per banner—External assets discouraged23 September 2026
Flashtalking (Innovid)Ad serverNo stated cap—vendor click APISupported—External assets discouraged23 September 2026
General usageStandards bodyNo stated cap—clickTag variableclickTagSupported—External assets allowed21 September 2026
Google Ad ManagerSSP1 MB zipped or unzipped—clickTag variableclickTagSupported—External assets discouraged21 September 2026
Google Ads (Display)Network600 KB zipped40vendor click APIOne per banner—Approved hosts only21 September 2026
Google StudioAd serverNo stated cap—vendor click APISupported30sExternal assets allowed23 September 2026
QuantcastDSP550 KB zipped—clickTag variableclickTagOne per banner30s—24 September 2026
Simpli.fiDSP250 KB zipped50click macroOne per banner—External assets allowed24 September 2026
Sizmek (Amazon Ad Server)Ad serversunsetting———One per banner——limits unverified
StackAdaptDSP750 KB zipped—clickTag variableclickTagOne per banner——limits unverified
The Trade DeskDSP10 MB zipped100clickTag on the ad URLclickTAGOne per banner15sExternal assets allowed22 September 2026
Xandr (Microsoft Advertising)DSPNo stated cap—clickTag on the ad URLclickTagOne per banner—External assets allowed21 September 2026
Yahoo DSPDSP1 MB zipped—clickTag variableclickTagOne per banner15sExternal assets discouraged20 September 2026

How to read this table

An em dash is not a zero. It means the platform publishes no figure for that constraint, or that we have not yet sourced one. We would rather print nothing than a number that gets your campaign rejected, so a cell is filled only when we can quote the document it came from.

Max ZIP size says what it measures. A cap on its own is ambiguous — 1 MB zipped and 1 MB unzipped are different numbers for the same bundle, and Google Ad Manager caps whichever of the two is larger. A creative that zips under the cap and expands past it is the most common way a package passes a naive checker and is still refused on upload.

Verified means sourced, not blessed. A dated row had every constraint read off the platform's own documentation on that date. An unverified row is not a guess — it shows only the fields we can cite and leaves the rest blank.

Can I use HTML5 banners on social platforms?

Choose the asset format for the placement. For standard image and video ads on Meta, TikTok, LinkedIn, Pinterest, Snapchat, Reddit and X, export an image or video in the placement’s required dimensions and file format. A display-banner ZIP from the matrix above is not a replacement for that asset. Video can preserve the animation, but individual clickable elements become part of the picture; set the ad’s destination in the platform.

Playable ads are a separate format.  TikTok accepts HTML5 ZIPs for playable ads, with its own SDK, packaging and campaign requirements. Meta Audience Network also offers playable ads. These placements need a dedicated playable integration; a standard HTML5 banner export does not establish compatibility.

Follow the linked official specifications for your placement. Format guidance reviewed 23 September 2026.

Common questions

What is the maximum file size for an HTML5 banner?
There is no single answer — it is set by the platform, not by the format. Among the platforms above the published caps run from 150 KB to 10 MB, and one states no cap at all. Check the row for the platform you are delivering to, and note whether the cap is measured zipped or unzipped.
Do I have to set the clickTag value before I export?
It depends on the platform. Most ad servers rewrite the clickTag at trafficking time, so an empty value in the file is correct and expected. Others never rewrite it, and an empty value ships a banner whose click area goes nowhere. Each platform page says which behaviour applies.
Can an HTML5 banner load fonts or libraries from a CDN?
On some platforms yes, on some only from an approved list of hosts, and on some not at all — everything must be inside the ZIP. It is one of the most common reasons an otherwise valid package is refused on upload, so it has its own column above.
How current is this data?
Each platform page carries the date its requirements were last read from the source, and every figure links to the document it came from. Records are re-verified periodically. This is an unofficial reference — confirm anything critical with your platform before delivery.

Every platform

Foldwrap exports native HTML5 to these platforms from one editable creative, and checks every package against the rules above before it is delivered. See how HTML5 export works.