Free HTML5 banner validator

Drop an HTML5 banner ZIP and see which ad platforms accept it. File size, clickTag, missing assets and external hosts — checked against the published rules of 16 platforms at once, each result linked to the document it came from.

Drop an HTML5 banner ZIP here

or

Checked against 16 platforms' published rules. The file is read in memory and discarded with the response — never written to disk.

Where can I ship this banner?

Most producers find out they have broken a platform's rule when the platform rejects the upload. This runs the check first. You get one row per platform, best fit first, and the constraint that decided each verdict — so "150 KB zipped" is something you learn here rather than after a failed trafficking attempt.

Every check comes from the same catalogue that powers the platform specs pages and Foldwrap's own export preflight, so a figure on this page and a figure on a platform page cannot disagree. No account, no email, no signup to see the result.

What this cannot check

Being honest about the limits of a free tool is the only way its verdict means anything. These are deliberately out of scope:

Animation duration and loop countnot readable from a finished archive without running the creative; known at export time, which is why the editor checks it and this cannot
Named exits and exit countan authoring-time concept, invisible in a finished bundle
Account eligibilityGoogle Ads' spend and account-age gate is about the account, not the file
Runtime behaviourCPU, audio and video policy, and expandable behaviour all need the creative to run
Anything on an unverified recordwe print what we can cite and stay silent on the rest

And the standing caveat: this cannot guarantee platform approval. Platforms change their specs without notice and apply placement-specific rules. It checks your package against the requirements published on the date shown on each platform's page.

Frequently asked

Is the HTML5 banner validator really free?
Yes. Drop a ZIP and the full result is shown — every platform, every check, no email and no account. The tool exists to answer the question you already have before you traffic the ad.
What happens to my banner file?
It is read into memory, checked, and discarded with the response. Nothing is written to disk, no account is required, and the only thing recorded is a one-way fingerprint of the archive plus its size and file count as buckets — never the content and never the filename.
Why does the result differ from platform to platform?
Because the platforms differ. One accepts a 10 MB package, another 150 KB; one allows external fonts, another refuses any reference outside the ZIP. One file can pass five platforms and fail four, and the matrix shows exactly which rule costs you which destination.
The result says "limits unverified" — is that a warning?
It is an honesty note, not a failure. It means we have not yet sourced every limit for that platform from its own documentation, so the verdict runs only on the fields we can cite. A green tick there means "nothing we can source is broken", not "approved".
Can it guarantee my ad will be approved?
No, and no tool can. Platforms change their specs without notice and apply placement-specific rules on top. This checks your package against the requirements published on the date shown on each platform page, and links every rule to the document it came from.

A bundle that fails a check means editing the creative and exporting again. Foldwrap builds one creative and exports a bundle per platform that passes these checks.

Export banners that pass these checks