Amazon Flat File Validator

This Amazon flat file validator checks an Amazon inventory file template — the tab-delimited spreadsheet you upload through Seller Central — for the structural and field-level problems that trigger listing errors before you ever submit it. Paste or upload your file and see exactly which rows and columns will be rejected, in plain language, so a CPG, furniture, or MRO catalog onboards cleanly the first time.

What it checks

The validator inspects the file the way Amazon’s processing report does, but instantly and before submission:

• Template structure — confirms the three header rows (the TemplateType signature line, the human-readable labels, and the machine field names like feed_product_type, item_sku, external_product_id) are present and in the right order.
• Required fields — flags rows missing values Amazon mandates for that product type, such as item_sku, product_id / external_product_id, product_id_type, brand_name, item_name, and feed_product_type.
• Identifier validity — runs UPC, EAN, and GTIN values through check-digit math and length rules, and confirms external_product_id_type matches the value supplied (a 12-digit UPC tagged as an EAN, for example).
• Controlled values — checks fields that only accept Amazon’s valid-value lists, like condition_type, currency, fulfillment_center_id, and unit-of-measure columns.
• Numeric and format rules — catches non-numeric prices, negative quantities, malformed dimensions, and dates not in the expected format.
• Duplicate SKUs — surfaces repeated item_sku values that would collide on upload.
• Encoding and delimiter integrity — detects stray tabs, broken UTF-8 characters, and quoting that shifts columns out of alignment.

How the Amazon flat file validator works

Amazon flat files are tab-delimited text exported from the category-specific inventory template you download in Seller Central. Each template carries its own required-field set keyed off feed_product_type, so a category like industrial fasteners demands different attributes than home furniture or packaged food. The validator parses the three-row header block, maps your columns to Amazon’s machine field names, then evaluates every data row against the rules for required presence, identifier check digits, controlled vocabularies, and numeric formats.

Identifier checks use the published GS1 standards — UPC-A and EAN-13 check-digit algorithms and GTIN length rules — rather than guessing, so a transposed digit in a barcode is caught deterministically. Controlled-value checks compare your entries against Amazon’s accepted lists for that field.

The tool reports problems, it does not invent data. Where a value is missing or malformed it tells you the row, the field, and the rule it failed, leaving the fix to you or to an automated enrichment step.

Related resources

FAQ

What is an Amazon flat file? +

An Amazon flat file is a category-specific, tab-delimited spreadsheet template you download in Seller Central and use to add or update many listings at once. It carries a header block that identifies the template type and the required fields for that product category, then one row per SKU.

Why does my Amazon flat file keep getting errors? +

The most common causes are a missing or wrong feed_product_type, absent required fields like item_sku or external_product_id, an identifier whose check digit or product_id_type does not match, values that fall outside Amazon’s accepted list for a field, or encoding and delimiter damage that shifts your columns. This validator flags each of those before you submit.

Do I need to upload my file anywhere to validate it? +

No. The validator runs entirely in your browser. Your inventory file is parsed locally and never sent to a server, so there is no login and no file-size cap beyond your own device’s memory.

Will this fix the errors for me? +

It diagnoses rather than rewrites: you get the exact row, field, and failed rule for every issue, but the corrections stay under your control. For large or recurring catalogs, an automated matching and enrichment layer can resolve the underlying records so clean files are generated rather than patched by hand.

Does it work for any Amazon category? +

Yes. Because the tool reads the feed_product_type and the machine field-name row from your template, it applies the required-field and identifier rules that correspond to your file — whether that is groceries, furniture, industrial supplies, or another category.