Barcode, SKU & FNSKU Labeling Best Practices
Why labeling discipline — SKU, barcode and marketplace FNSKU — is the operational backbone of accurate fulfillment from China, with practical rules for getting it right.
Published October 3, 2026
Labels are the unglamorous backbone of fulfillment. A wrong label sends the right product to the wrong customer, or merges your inventory with a stranger’s. For sellers fulfilling from China — especially into marketplaces — labeling discipline isn’t clerical, it’s operational survival.
The three identifiers
- SKU — your internal stock-keeping unit; the human-readable ID you manage by.
- Barcode — the scannable encoding of the SKU, used at receive, pick and pack.
- FNSKU — Amazon’s fulfillment network SKU; required to keep your inventory separate from others’ in commingled storage.
They’re related but not interchangeable. Use each where its system expects it.
Why mislabels are expensive
A mislabeled unit can be:
- Received under the wrong SKU (inventory lies)
- Picked for the wrong order (customer gets the wrong item)
- Commingled on a marketplace (your stock ships to someone else’s buyer)
One bad label cascades into refunds across multiple orders.
Practical rules
- Print quality — high contrast, no smudging; test scans before mass application.
- Placement — flat, unobstructed, on a consistent face of the unit or carton.
- Standard per SKU — one labeling spec per SKU, documented, followed at pack-out.
- Marketplace compliance — apply FNSKU where required; don’t assume your SKU barcode suffices.
At the China warehouse
Build labeling into the pack instruction. The warehouse should apply the correct labels during pack-out, not as a separate guessing step. Verify a sample of each run scans correctly.
The takeaway
Labeling is where fulfillment accuracy is won or lost. Define one standard per SKU, print and place it correctly at pack-out, and apply marketplace IDs where required. Clean labels are clean inventory.