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September 2, 2026 · SKU Monster

You scanned a pallet of barcodes, exported the list, and now you're staring at a spreadsheet of GTINs with no titles, no specs, and no images. Amazon and eBay both want a listing, but each has its own image rules and its own idea of "complete." Doing this SKU-by-SKU, marketplace-by-marketplace, is where liquidation and wholesale sellers lose their weekend.

This guide shows a repeatable way to turn a raw barcode list into two ready-to-upload listing sets at once, without hand-shooting a single photo or copy-pasting spec sheets.

What You'll Learn

Why Barcode Photos Fail Both Marketplaces

The photos you take on the receiving dock — box on a shelf, barcode label in frame, a bit of pallet wrap — are useless as listing images, and both marketplaces will tell you so.

Amazon requires main images to be professional, on a pure white background, showing only the product and filling roughly 85% of the frame. Images under 500 px on the long side can't be uploaded at all, and Amazon recommends 1,000+ px so the zoom feature works. It accepts JPEG, TIFF, PNG, and non-animated GIF, and it's picky about filenames: they must follow the product-identifier pattern using periods only — spaces or dashes can block the upload outright.

eBay is looser on size but still strict on presentation. It wants a minimum of 500×500 px, allows up to 9,000×9,000 px, and accepts formats including PNG, JPEG, TIFF, BMP, and GIF. Critically, eBay's guidance says listing photos should not include borders, logos, barcodes, or copyright marks — which means your barcode-heavy internal photos are exactly what eBay tells you to avoid.

The takeaway: a barcode is a great key, but a terrible image. You need something that turns the key into clean, white-background product images and structured specs that satisfy both rulebooks.

Step 1: Turn One Barcode Into Data + Images

SKU Monster is built around exactly this problem. Given a GTIN (EAN / UPC / barcode), it finds and generates clean, studio-quality, white-background product images plus structured product data — name, brand, category, and specs. It's an automated image and data pipeline, not a manual photo shoot, which is why it costs $2 per SKU instead of the $250–$1,500 per SKU that traditional product photography runs.

Start with the free lookup on the home page to see the shape of what comes back for a single barcode before you commit to a batch. When you're ready to script it, the product lookup is a single call:

GET https://sku.monster/api/v1/barcode?code=0000000000000
x-api-key: <your-key>

An illustrative response shape (generic identifier, minimal fields):

{
  "identifier": "0000000000000",
  "name": "Example Product Name",
  "brand": "Example Brand",
  "category": "Example Category",
  "specs": { "...": "..." },
  "images": [ "..." ]
}

Treat that as the shape only — your real fields come back for your real barcodes. If you need to trigger image generation explicitly for an identifier, the POST /api/v1/images and POST /api/v1/studio endpoints handle studio image jobs. Full request and response details live in the API docs.

Step 2: Bulk-Process the Whole List

One barcode is a demo. A liquidation lot is the real job. The POST /api/v1/batch endpoint bulk-processes many barcodes in a single request, so you feed it your exported GTIN list and get structured data plus generated images back for the set.

A sane bulk workflow looks like this:

  1. Export your barcode list from your inventory system into a flat list of GTINs.
  2. Send that list to POST /api/v1/batch.
  3. Store the returned name, brand, category, and specs as your single source of truth.
  4. Pull the generated white-background images for each SKU.
  5. Map those fields and images into two separate export templates — one for Amazon, one for eBay.

Because everything derives from one dataset, your Amazon title and your eBay title describe the same product with the same attributes. That consistency is what makes cross-channel profit tracking possible later — sellers repeatedly report that barcode scanning speeds up lookup and relisting, but that the real pain is cleaner inventory-to-export matching so profit tracking actually lines up. One canonical record per barcode solves that at the source.

If you sell in multiple regions, check GET /api/v1/markets for supported pricing markets and GET /api/v1/languages for translation languages before you build your templates, so you're not rebuilding the mapping later.

Step 3: Format for Each Marketplace's Rules

This is where "at the same time" gets real: the same source data, formatted two different ways.

For Amazon, take the generated white-background image as your main image. Confirm it meets the pure-white, product-only, ~85%-fill requirement and is at least 500 px (aim for 1,000+ px for zoom). Rename files to Amazon's identifier-plus-periods pattern — no spaces, no dashes — or the upload will silently fail. Amazon's guidance also recommends at least six additional images and a video for a complete listing, so plan your main image as the anchor and build supporting images around it where you have them.

For eBay, use the same clean image set, verify each is at least 500×500 px, and confirm there are no borders, logos, barcodes, or copyright marks in frame — which is exactly why you're using generated studio images instead of your dock photos. eBay accepts a wider set of formats, so you rarely need to convert.

Because SKU Monster's images are white-background and product-only by design, one image set generally clears both rulebooks with only filename and size housekeeping between them.

Step 4: Keep the Margin Math Honest

Duplicating inventory across channels multiplies fees, and eBay's structure hits volume sellers specifically. eBay gives you the first 250 listings per month free, then charges $0.35 per additional listing. Its final value fee is 13.6% of the total sale amount up to $7,500, plus 2.35% on the portion above that.

Run those numbers against your landed cost before you mass-list, not after. The advantage of a single structured record per SKU is that you can attach cost, target price, and fee assumptions to the same canonical row that feeds both channels — so when a unit sells on eBay versus Amazon, you already know which margin you captured. That's the "cleaner inventory/export matching for profit tracking" sellers keep asking for, and it starts with clean, consistent product data.

Summary

To bulk-list barcode inventory on Amazon and eBay at the same time, stop treating each SKU and each marketplace as a separate manual task. Turn every barcode into one canonical record of structured data plus clean white-background images, then format that single source into two upload templates that each satisfy their marketplace's image and filename rules. This keeps titles and specs consistent, keeps your images marketplace-ready on both platforms, and keeps your fee and margin math attached to one row per SKU. It's the difference between a weekend of copy-paste and a scripted batch run.

Ready to Try It?

Run a real barcode through the free lookup, then batch your whole list. Create your account and start listing — $2 per SKU, no subscription.

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