Is Google's HTML5 Validator shut down?

Not as of October 2026: h5validator.appspot.com still loads. Google has announced its retirement more than once and postponed it, and points to validation inside Campaign Manager 360 and Display & Video 360 instead, so treat it as a tool that may disappear.

Is there a free HTML5 ad validator that does not upload my files?

Yes. The check on this page reads the ZIP or folder in your browser; the file never leaves your machine. The desktop app and the CLI also run locally.

Does passing a validator mean the ad will be approved?

No. A validator checks the package against technical specs. Account, policy, landing-page and manual review decisions happen on the platform, and runtime problems such as a blank render or Heavy Ad Intervention are not visible to a file check.

Can I check one creative for Google Ads, DV360 and CM360 at the same time?

Yes, in the Ad-Preflight desktop app. It applies each platform's own rules and shows a verdict per platform, per size, across the whole campaign folder.

HTML5 ad validator comparison

Google HTML5 Validator alternative: check one ad against every platform, without uploading it

Google's HTML5 Validator checks one platform per upload, on Google's server. Ad-Preflight checks a ZIP in your browser for free, and the desktop app gives a verdict for Google Ads, DV360, CM360 and CM360 Studio at once, fixes safe issues and runs the ad to measure it.

The short version

A creative passes the validator for one platform and is rejected by the next, or passes every validator and still goes blank or gets removed by Chrome once it runs. A file validator answers "is this ZIP well formed for platform X?". Production needs "where will this ad upload, and will it work when it runs?".

Check your creative now: ZIP, folder or ad tag

LOCALYour browser reads the file. Nothing is uploaded.

Preflight check

Drop a creative ZIP or folder here

One creative at a time. The verdict appears right here.

Choose ZIP…Choose folder…

What Google's HTML5 Validator is good at

Google's validator (h5validator.appspot.com) is free, it is Google's own reading of its rules, and it has separate pages for Campaign Manager, Display & Video 360 and Google Ads. If a creative is going to one Google platform and you only need a yes or no on the package, it is a reasonable first check.

Google has announced its retirement more than once and later postponed it, and has said validation is moving into the platforms themselves. It was still online at the end of October 2026, but it is not a tool to build a production process on.

Where a validator stops

•One platform per run. The same ZIP can be fine for DV360 and over the 600 KB Google Ads limit, so a multi-platform campaign means one upload per platform per size.
•The files go to a server. Unreleased campaigns and client work under NDA leave your machine.
•It reports, it does not repair. A missing ad.size meta or a clickTag bound to the wrong element still has to be fixed by hand and re-uploaded.
•It inspects files, it does not measure the running ad. JavaScript errors, blank renders and Chrome's Heavy Ad CPU and network limits only show up when the creative executes.

What Ad-Preflight does instead

•Free, in this page: drop a ZIP or folder and it is checked in your browser. Nothing is uploaded.
•Desktop app: tick the platforms the campaign is going to and get one stamp per platform with the reason, for example "Ready for DV360 and CM360. Not Google Ads: 970x250 is 640 KB, over its 600 KB limit."
•Safe automatic fixes for common packaging and markup problems, then upload-ready ZIPs for every size.
•Deep Audit runs each size in a real local browser and reports JavaScript errors, blank renders, network use and Heavy Ad risk.
•The same checks run from a terminal or CI pipeline through the CLI.

What Ad-Preflight checks

✓ZIP structure, file types and weight per platform
✓ad.size meta and declared dimensions
✓clickTag, exit and Enabler rules per platform
✓HTTPS references and missing assets
✓Per-platform verdict across a whole campaign (desktop app)
✓Runtime errors, blank render and Heavy Ad risk with Deep Audit

What it cannot guarantee

!It is not Google: platform rules can change before our rules are updated
!It cannot reproduce account, policy or manual review decisions
!The free browser check covers the static checks; per-platform verdicts and Deep Audit are in the desktop app

Run it in the desktop app or CLI

Designers and AdOps can drop a campaign folder into the desktop app and follow the visual report. If you work in a terminal or CI pipeline, the same checks are available through the CLI.

1.Drop the campaign folder or ZIPs into the desktop app.
2.Tick the platforms the campaign is going to.
3.Apply the safe fixes and read what is left in the verdict box.
4.Run Deep Audit, then package the upload-ready ZIPs for AdOps.

CLI equivalent

npx @ad-preflight/cli package ./my-ad --fix

Questions

Is Google's HTML5 Validator shut down?: Not as of October 2026: h5validator.appspot.com still loads. Google has announced its retirement more than once and postponed it, and points to validation inside Campaign Manager 360 and Display & Video 360 instead, so treat it as a tool that may disappear.
Is there a free HTML5 ad validator that does not upload my files?: Yes. The check on this page reads the ZIP or folder in your browser; the file never leaves your machine. The desktop app and the CLI also run locally.
Does passing a validator mean the ad will be approved?: No. A validator checks the package against technical specs. Account, policy, landing-page and manual review decisions happen on the platform, and runtime problems such as a blank render or Heavy Ad Intervention are not visible to a file check.
Can I check one creative for Google Ads, DV360 and CM360 at the same time?: Yes, in the Ad-Preflight desktop app. It applies each platform's own rules and shows a verdict per platform, per size, across the whole campaign folder.

Platform reference: Google HTML5 Validator (Campaign Manager)