What is an FNSKU?
The FNSKU is an Amazon-specific barcode used to uniquely identify products in the FBA process. It helps Amazon identify items in the warehouse, sort them correctly, and assign them to the appropriate seller’s inventory.
For Amazon FBA, the following applies: Every unit sent to an Amazon fulfillment center must have a scannable barcode. Depending on the product, this can be a manufacturer’s barcode such as EAN or UPC—or an Amazon barcode such as the FNSKU.
The FNSKU is frequently used, particularly for private-label products, reseller merchandise, or products that cannot be tracked using the manufacturer's barcode.
Amazon requires a barcode - not an adhesive label
When it comes to FNSKU labeling, many sellers immediately think of a label printer. This is understandable, as FNSKU labels are widely used in day-to-day Amazon FBA operations.
What matters is not the adhesive label itself, but rather a label that is reliably readable and correctly assigned.
In practice, the traditional labeling process involves:
- Set up a label printer
- Preparing Amazon FBA Labels
- Manage label rolls
- Assign the correct SKU
- Apply labels
- Check the position and legibility
- Rework defective labels
This is usually quite manageable for small quantities. But when dealing with larger quantities, frequent SKU changes, or handling FBA preparation in-house, it becomes clear that proper barcode labeling is essential. However, the real effort often lies in the handling process.
The problem with classic FNSKU labels
The higher the quantity and the number of items, the greater the risk:
- Labels are swapped
- Labels are applied too quickly or half-heartedly
- Edges stick out
- Labels come loose in the storage process
- Labels are placed at the edge
- additional control effort arises
In addition, the product appearance often suffers. Amazon requires a minimum size of 1″ × 2″ for FNSKU codes. This results in relatively large white label areas that are immediately noticeable on cardboard or high-quality packaging.
Brands with high-quality or sustainable packaging in particular often find this annoying. Many Amazon FBA sellers are therefore looking for alternatives to the classic FNSKU label or manual Amazon FBA labeling.
In e-commerce, packaging is increasingly becoming a key factor in purchase and repeat purchase decisions. According to the Mondi & RetailX E-Commerce Study 2026, 98% of consumers expect packaging to match the quality of high-end products. 67% say that packaging features contribute to a positive unboxing experience and encourage repeat purchases.
Mobile direct printing replaces the labeling step
An alternative to traditional labels is mobile direct printing. With this method, the FNSKU code is not first printed on an adhesive label and then affixed, but is applied directly to the packaging.
With the jetStamp® 1025, barcodes, text, and other information can be printed directly onto suitable packaging—such as cardboard boxes, folding cartons, or shipping containers.
The print image is stored digitally in the device and selected based on the application. The code is then printed directly onto the packaging.
This eliminates the need for the labeling step:
- no label rolls
- no backing material
- no manual application
- no protruding label edges
- less material waste
- less rework due to incorrectly or poorly applied labels
The FNSKU code becomes an integral part of the packaging label. However, its suitability always depends on the packaging material, surface, ink, contrast, and scannability.
Why this is interesting for FBA processes
FNSKU direct printing becomes particularly appealing when labels become a nuisance in everyday life – As a rough guide, starting at about 50 units per day, depending on the process, product, and frequency of changeovers.
For example:
- for regular FBA shipments
- for medium or large quantities
- with frequent SKU changes
- at prep centers and fulfillment service providers
- for private-label products
- for high-quality or sustainable packaging
- when the use of label and backing materials needs to be reduced
The advantage: The required code is applied directly during the packaging process. No separate adhesive label. No sticking. No extra label edge.
Amazon requirements in comparison
The same applies to direct printing: The barcode must be reliably readable, correctly positioned, and uniquely assigned. Therefore, every application should be tested before use.
| Amazon request | What matters | REINER jetStamp® 1025 |
|---|---|---|
| Scannable FNSKU code | Reliable readability during the process | Barcode quality up to Grade 4.0 (A) is possible* |
| Sufficient print area (minimum size 1 × 2 inches) | Space for barcode and plain text | 1-inch print height × up to 85 mm print length |
| 1D barcode | FNSKU from Seller Central | You can print 1D barcodes from Seller Central |
| Good barcode quality | Sharp edges, good contrast | Up to 300 dpi |
| Suitable surface | Adhesion, Drying, Readability | Particularly suitable for cardboard |
*Depending on the surface, ink, contrast, and print image.
This makes the jetStamp® 1025 suitable for direct printing of Amazon FNSKU barcodes on compatible cardboard packaging, folding cartons, or shipping boxes.
Successfully tested on brown cardboard
In a field test, an FNSKU was printed directly onto brown cardboard. The Amazon FBA barcode printed directly onto the cardboard was successfully processed in the subsequent steps.
This shows that FNSKU direct printing on cardboard can be a viable alternative to traditional adhesive labels.
However, keep in mind that the result always depends on the packaging, the print area, the ink, the contrast, and the scanability. That is why we recommend doing a test print on the original packaging before use.
In addition to brown cardboard, white cardboard, folding boxes, or selected shipping packaging can also be tested, depending on the application.
Less effort in the packaging process
The FNSKU is still necessary. The adhesive label isn't always.
With mobile direct printing, Amazon sellers, prep centers, and fulfillment service providers can integrate labeling directly into the packaging process. This helps reduce label material, manual steps, and potential sources of error.
FNSKU direct printing can be an efficient alternative to the traditional Amazon FBA label, especially for recurring products, larger quantities, and suitable packaging surfaces.
Conclusion: Simplify the preparation of FNSKU labels
Anyone who regularly prepares products for Amazon FBA knows how much work FNSKU labels entail. Printing, assigning, applying, and checking—each step takes time and can lead to errors.
Direct printing can simplify this process. FNSKU codes are printed directly onto suitable packaging—without a separate adhesive label or additional backing material.
Whether your packaging is suitable depends on the material, surface, print quality, contrast, and scannability.
Check now whether your packaging is suitable for FNSKU direct printing.
Send us your application or a packaging sample. Together, we’ll determine which ink, print image, and solution are best suited for your process.
Important note before we begin:
Existing barcodes such as EAN, GTIN, or manufacturer barcodes cannot be overprinted or rendered unreadable with the jetStamp 1025, as this would prevent the creation of a reliably readable FNSKU code. In this case, an easily removable label is the only solution.
The FNSKU direct print should be made on a free, easily scannable surface of at least 27 × 55 mm.
Alternative: If there is no free printing area or existing EAN/GTIN codes need to be covered, the product can also be packaged in additional paper-based packaging (e.g. paper bag or cardboard sleeve). This surface can then be marked directly with the jetStamp 1025.
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