How To Choose And Implement Product Identifiers For eCommerce Platforms

Product Identifier A code or value used to uniquely or consistently identify a product, such as a SKU, GTIN, UPC, EAN, or MPN. Implementing the right identifiers and governance prevents listing rejections, shipping errors, and inventory mismatches.

Implementation covers selection, assignment, data capture, and distribution of identifiers across WMS, PIM, ERP, marketplaces, and carrier labels. A practical rollout plan ensures regulatory and marketplace compliance while keeping warehouse processes efficient.

Step 1 — Decide Which Identifiers You Need

• External Visibility: GTIN/UPC/EAN for marketplaces and search engines.
• Manufacturer Data: MPN when selling branded or technical items.
• Internal Operations: SKU for warehouse location, batch, and variant tracking.

Step 2 — Obtain Or Validate Standard Identifiers

If you are a brand owner, obtain GTINs from GS1 so the numbers are registered and recognized. If reselling, validate manufacturer-supplied GTINs against GS1 or the manufacturer’s catalog. For exempt items (custom or handmade goods), document the exemption policies of each marketplace to avoid delisting.

Step 3 — Build Identifier Governance

• Ownership: Assign a data steward responsible for SKU schema, GTIN mapping, and feed quality.
• Standards: Define SKU structure, character sets, and length limits to ensure compatibility with WMS and ERP systems.
• Validation: Implement checks (format, checksum for GTIN) when onboarding new products.

Step 4 — Integrate Across Systems

Store authoritative identifier fields in your PIM or master catalog and expose them to downstream systems. Configure your WMS to print labels (with human-readable SKU and barcode for GTIN) and to scan incoming GTINs or supplier barcodes during receiving. Ensure your marketplace feeds include GTIN and MPN fields where required.

Step 5 — Labeling And Barcode Best Practices

• Barcode Quality: Verify print contrast, quiet zones, and placement for reliable scanning at pick and pack.
• Label Content: Include both SKU and GTIN on shelf and shipping labels so staff and systems can use either identifier.
• Variant Handling: Use distinct GTINs for different sizes/colors; use variant SKUs within a common parent product record.

Step 6 — Marketplace And Channel Requirements

Each channel has rules: some require GTINs for new listings, others allow MPNs or exemptions. Before launching, consult channel help pages and test sample feeds. Maintain feed logs and error handling to correct invalid or missing identifiers promptly.

Practical Implementation Example

A merchant launching a new apparel line registers GTINs via GS1 for each SKU variant. They create an SKU scheme that encodes season, style, and size, store all identifiers in their PIM, and push product feeds to marketplaces containing GTIN and MPN fields. Warehouse labels show both SKU and GTIN barcodes. On receiving, the WMS validates incoming GTINs against the PIM to confirm the item and location before binning.

Tips For Ongoing Management

• Monitor Feed Quality: Use automated reports to catch missing GTINs or format errors before they affect listings.
• Audit Regularly: Periodically reconcile physical inventory GTINs and SKUs to the master catalog.
• Train Staff: Teach receiving and picking teams to recognize and scan both SKU and GTIN labels to reduce errors.

In short, the Product Identifier is both a technical requirement and a business process. Choose global identifiers for external sales, maintain disciplined SKU governance internally, and integrate identifier validation and labeling into your operational workflows to keep listings accurate and fulfillment efficient.