EAN/GTIN: how to unify the same product across Amazon and MercadoLibre

If you sell across channels, your biggest data problem isn’t lack of information: it’s that the same product shows up with different identities in each place. The fix is called EAN/GTIN.

What it is and why it matters

The GTIN (Global Trade Item Number) — of which the 13-digit EAN is the most common variant — is the universal code for a physical product. Unlike the SKU (which everyone invents their own way) or the ASIN/MLM (channel-specific), the GTIN is the same everywhere. It’s the only reliable key to say “this Amazon product and this MercadoLibre one are the same.”

The problem with unifying by SKU

• Your internal SKU may not match Amazon’s seller-sku.
• On MercadoLibre the same product can have multiple MLM and family_ids.
• A product with variants (size/color) multiplies identifiers.

Result: if you unify by SKU, you end up with duplicates, mis-summed stock and margins that don’t add up.

How to unify it right

1. Assign the correct GTIN to each physical product (including each color/size variant).
2. Map downward: one GTIN groups all the SKUs/ASIN/MLM that belong to it.
3. Define a “family” level (parent model) to group variants when needed.
4. Validate discrepancies: duplicate, missing or mismatched GTINs across channels.

The model that scales

The structure that works has three levels: family (model) → variant (physical product, joined by GTIN) → listings (each channel’s SKU/ASIN/MLM). That way a stock or price change is understood at the real-product level, not per loose listing.

In short

EAN/GTIN is the backbone of a healthy multichannel catalog. Unifying there — not by SKU — is what enables real inventory, correct margins and reports that add up. iqseller crosses your channels by GTIN automatically and shows you the discrepancies.

Want your catalog unified by GTIN? Join the beta waitlist.