Upload a flat file with a duplicate SKU or a broken parent–child link and Amazon rejects it hours later, in a processing report written for machines. This checks the file on your own computer first, in seconds, and tells you which row is wrong.
Every other tool in this category asks you to create an account and upload your product data to their servers. This one does the parsing in your browser. There is no server to upload to, because there is no server.
The file is read in the browser tab. Your SKUs, prices, and supplier data stay on your disk. Close the tab and nothing remains anywhere.
No email, no password, no onboarding call. Open the page, drop the file, read the results.
Pay once and large-file checks stay unlocked. No renewal, no expiry, nothing to cancel later.
Deliberately not a full validator. It looks for the structural mistakes that cause a rejected feed, not for every rule in Amazon's category templates.
It reports what it finds and links each finding to the row. It does not edit your file, fix anything for you, or promise that Amazon will accept the upload — only that these specific errors aren't in it.
This is a checker, not a catalog platform. If you need the things on the right, buy one of those instead — they're good at it.
You already have a flat file and want to know what's wrong with it before uploading.
You need the file built for you from a Shopify export, ERP dump, or supplier CSV.
You don't want your catalog on someone else's server, or you can't put it there.
You want AI mapping, auto-correction, and a hosted team workflow.
You upload occasionally and don't want a monthly bill for it.
You manage catalogs daily and a subscription pays for itself.
Check the first 30 rows of any file for free, as many times as you like, without an account. That's enough to see whether it finds anything useful in your data before you spend anything.
Written for the problem, not for the product. Useful whether or not you ever buy anything here.