Free Amazon seller tool

Amazon Flat File Inventory Checker — Catch Errors Before You Upload

One bad row can hold up an entire Inventory Loader upload. Paste or upload your Amazon inventory file — any Amazon inventory loader file or spreadsheet export — to catch blank SKUs, duplicate rows, bad prices, and broken columns in seconds.

Free forever No signup Private — runs in your browser
  • Free forever
  • No signup
  • Heuristic checks
  • Cleaned-file download
Free

Flat-File Preflight Validator

Amazon's processing reports tell you something failed — rarely what. This validator runs a battery of heuristic checks over your completed flat file before you upload: blank or duplicate SKUs, non-numeric or negative prices and quantities, invalid add/delete codes, image URLs that don't look like URLs, and dates that aren't really yyyymmdd. Pick your template type for stricter required-column checks, then download the whitespace-trimmed, blank-row-cleaned file.

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Flat file: pro tips

  1. Pick the right template type before validating. Generic catches universal problems, but the Inventory Loader and Listing Loader checks enforce the required columns for that template — the stricter pass is where the real upload-killers surface.
  2. Fix blank and duplicate SKUs first. One duplicate SKU can cascade into dozens of errors in Amazon's processing report, burying the one genuine problem. SKU hygiene resolves most "mysterious" flat-file failures.
  3. Upload the cleaned download, not your original file. The validator's download is whitespace-trimmed with blank rows removed, so the file Amazon sees is exactly the file you validated — no more phantom errors from trailing spaces or empty lines.

Why check your Amazon inventory file before uploading?

A single bad row — a blank SKU, a price with a dollar sign, a date in the wrong format — can hold up an entire upload, and Amazon's processing report makes you hunt for which one. On catalogs with thousands of rows, eyeballing the file is not a strategy.

This checker preflights your Amazon inventory file in seconds: duplicates that would overwrite each other, quantities that aren't numbers, columns your template requires but your file is missing. Whether you built the file by hand or started from an Amazon download inventory file export, it validates structure against the Inventory Loader format — always cross-check flagged rows against the official template before re-uploading. If you are still learning how to send inventory to Amazon, think of the flat file as the vehicle: one clean upload replaces hours of manual listing edits.

Also free: Inventory Loader Generator · Bulk Sheet Validator · Listing Copy Length Checker

How do I check my Amazon inventory file?

Paste, upload, or both:

  1. Paste your flat file into the box, or upload the CSV/TSV/TXT file — or do both at once.
  2. Pick the template type so the validator knows which columns are required (Inventory Loader expects price and quantity; Listing Loader expects price).
  3. Hit Validate to see every issue by row number — or a green all-clear.
  4. Download the cleaned file (whitespace trimmed, blank rows removed) and fix any flagged rows before you send your inventory to Amazon.

Watch how it works

Flat-File Validator FAQs

Yes — free forever, no signup. It runs entirely in your browser, so nothing you paste or upload is sent anywhere.
Any tab- or comma-delimited Amazon inventory file: Amazon inventory loader files, listing loader spreadsheets, and Amazon inventory spreadsheet exports. Pick the template type so the checker knows which columns your file needs before you send your inventory to Amazon.
A missing or unrecognized SKU header, blank SKUs, duplicate SKUs, non-numeric or negative prices, non-integer or negative quantities, add-delete codes outside the allowed set, image fields that don't look like URLs, and date fields that aren't valid yyyymmdd dates. It validates structure, not your category's required attributes — always cross-check against the template from Seller Central for your category.
It sets which columns are treated as required. Inventory Loader mode requires price and quantity columns; Listing Loader mode requires price; Generic mode only checks whatever columns it finds.
It trims leading and trailing whitespace from every cell and drops fully blank rows — the two most common causes of mysterious upload failures. Content fixes (bad prices, duplicates) are still yours to make.
Nowhere. The file is parsed and checked inside your browser tab. Your catalog data never touches our servers.

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