Amazon Flat Files Explained: A Beginner's Guide

Flat files are Amazon's bulk upload format — tab-separated spreadsheets that let you create or update multiple listings at once. They're powerful but painful. One wrong cell can suppress a listing or break a variation family. Here's how they actually work.

What Is a Flat File?

A flat file is a .tsv (tab-separated values) file with a specific structure defined by Amazon for each product category. Every column represents a product attribute — SKU, title, price, bullet points, images, variations, and dozens more depending on your category.

You download the template from Seller Central, fill it in, and upload it back. Amazon processes the file and creates or updates your listings.

Required Fields (Every Category)

These fields must be populated in every flat file: - SKU: Your unique identifier for the product - Product Title: Subject to all Amazon title rules - Price: Must be competitive - Quantity: Inventory count - Product ID: UPC, EAN, or GTIN - Product Type: Determines which attributes are required - Brand: Must match your Brand Registry - Condition: New, Used, Refurbished

As of 2025, Product Type is mandatory and determines your variation themes and required attributes. Get this wrong and the entire file will be rejected.

Parent-Child Variations

This is where flat files get complicated. A variation family has one parent listing (the main product page) and multiple child listings (the individual buyable items).

In the flat file: - Parent row: Set parent_child to "Parent", add your variation_theme (Size, Colour, SizeColor, Style, Pattern) - Child rows: Set parent_child to "Child", set parent_sku to your parent's SKU, set relationship_type to "Variation", and fill in the variation values (size_name, color_name)

The parent row contains the shared title, description, and images. Child rows contain the specific size, colour, price, and quantity.

Common Errors That Break Uploads

• +Missing required fields: Amazon rejects the entire row silently
• +Wrong category template: Each category has different required fields — using the wrong template means nothing matches
• +Character encoding issues: Accented characters (é, ü, ñ) must be UTF-8 encoded or they'll corrupt
• +Exceeding character limits: Title over the category limit, bullets over 500 characters, description over 2,000
• +Duplicate SKUs: If a SKU already exists, the file will overwrite it — including deleting fields you left blank
• +Wrong variation theme: If your category doesn't support SizeColor variations, the file will fail

Flat File Tips

Always download the latest template — Amazon updates them frequently. Never edit a flat file in Excel without setting the encoding to UTF-8 (Excel loves to corrupt special characters). Test with a single SKU before uploading hundreds. Keep a backup of every file you upload.

The Easier Way

Tools like ListingForge generate flat files automatically from your listing data. Upload a product image, select your marketplaces, and download flat files in Amazon's exact format — with all the parent-child variation fields, SKUs, and marketplace-specific content already populated. No spreadsheet editing required.