FBA prep centers receive, inspect, label, package, and ship seller inventory to Amazon fulfillment warehouses in compliance with FBA packaging rules. That one sentence covers the service, but the actual work inside a prep center spans a dozen distinct tasks and a surprising amount of software. Here is what sellers get when they hand off a container, pallet, or small-parcel delivery to a prep partner.
Receiving and Inbound Inspection
The first service is simple on paper and messy in practice: taking delivery of inventory from suppliers. A prep center receives containers from overseas factories, LTL pallets from US wholesalers, parcels from retail arbitrage buyers, and dropshipped cases from distributors. Each shipment gets counted against the PO, photographed, and logged into a warehouse management system. Shortages, damaged cartons, and mislabeled SKUs are documented before the seller gets charged for prep work on units that never arrived.
Claim: 86% of Amazon sellers use FBA for at least part of their inventory. Source: Jungle Scout State of the Seller Report 2024 Date: January 2024
Inspection also catches problems Amazon would otherwise flag at the fulfillment center. Expired dates, missing suffocation warnings on poly-bags, broken retail packaging, and products that do not match the ASIN all get caught here instead of becoming stranded inventory.
FNSKU Labeling and Barcode Compliance
Every unit sent to FBA needs an FNSKU label unless the seller is enrolled in commingled stickerless inventory, which most brand owners avoid. Prep centers print FNSKU labels from Seller Central, cover existing UPC or EAN codes so they do not scan at Amazon’s receiving stations, and apply the labels to the correct face of the package. For products with multiple scannable surfaces, prep teams know which codes to block and which to leave visible.
Labels sound trivial until you have 8,000 units with two existing barcodes and a factory UPC that conflicts with Amazon’s catalog. A prep center turns that into a repeatable workflow.
Poly-Bagging, Bubble Wrap, and Protective Packaging
Amazon has specific packaging requirements that trip up new sellers. Any unit with openings (bottles, apparel, loose parts) typically needs a poly-bag with a suffocation warning printed in the right font size when the bag opening is 5 inches or larger. Fragile items need bubble wrap. Liquids need double-sealing. Sharp items need safety packaging.
Claim: Amazon third-party sellers accounted for 62% of paid units sold on Amazon in Q1 2024. Source: Marketplace Pulse Date: April 2024
Prep centers stock the right bag thicknesses (typically 1.5 mil or 2 mil), pre-printed suffocation warning bags in common sizes, and bubble mailers. For sellers who want to understand the full compliance picture, see what Amazon prep covers and when to outsource.
Bundling, Kitting, and Multi-Pack Creation
Many ASINs are not single-unit listings. A seller might run a 3-pack bundle, a variety set, or a gift kit combining items from different suppliers. The prep center assembles these: combining the component SKUs, sealing them together with shrink wrap or a branded sleeve, applying a single FNSKU to the bundle, and treating the finished bundle as one sellable unit.
Kitting is where prep centers earn their per-unit margin. It is labor-intensive, hard to automate, and critical to listings that depend on bundle math for competitive pricing. Pricing for kitting typically runs separately from basic prep. For context on how 3PLs structure these fees, see how pick-and-pack pricing works.
Shipment Plan Creation and Carrier Routing
Once units are prep-ready, the prep center creates the inbound shipment plan in Seller Central: selecting the SKUs and quantities, letting Amazon split the shipment across fulfillment centers (or paying the Inbound Placement Service fee to send everything to one), printing FBA box labels, and booking the right carrier. Small shipments go via Amazon Partnered Carrier UPS. Pallet shipments go LTL through Amazon Partnered Carrier or an outside freight broker.
Claim: Amazon’s US third-party seller services revenue reached $140.1B in 2023. Source: Amazon 2023 Annual Report Date: February 2024
Good prep centers track Amazon’s placement fees and FEM (fulfillment network) assignments to minimize split shipments and reduce the Inbound Placement Service charges that Amazon rolled out in 2024.
Storage, Returns Processing, and Removal Orders
Between inbound and outbound, inventory sits somewhere. Prep centers offer short-term and long-term storage priced per cubic foot or per pallet position, usually at rates well below Amazon’s long-term storage fees. Sellers use this buffer to send inventory to FBA in waves instead of all at once, which protects against Amazon’s inventory performance limits and IPI score penalties.
Returns processing is the mirror image of inbound. Amazon ships customer returns and removal orders back to the prep center address. Staff grade each unit (new, used-like-new, used-good, damaged), repackage sellable units for a second trip to FBA, and dispose of or return the rest to the seller. This recovers inventory that would otherwise be written off.
Claim: The average FBA fulfillment fee for a standard-size 1 lb unit was $3.86 as of 2024. Source: Amazon Seller Central Fee Schedule Date: January 2024
Multi-Channel Fulfillment and Wholesale Pick-and-Pack
Most modern prep centers do more than FBA. The same facility ships direct-to-consumer orders from Shopify, Walmart Marketplace, TikTok Shop, and eBay, pulling from the same inventory pool. For brands selling into independent retail or corporate gifting, the prep center also handles wholesale pick-and-pack: pulling case-pack quantities, palletizing, and shipping LTL to retailer DCs or gifting platforms.
This is where prep infrastructure overlaps with wholesale distribution. A brand holding inventory at a prep facility can fulfill an FBA replenishment, a Shopify order, and a 50-case wholesale PO from the same stock. Catalist works with b2b wholesale platforms that include prep and fulfillment for Amazon FBA specifically because sellers increasingly want one 3PL covering every channel. For vetting criteria when choosing a facility, review what to look for in an FBA prep center.
Putting It Together
An FBA prep center is a specialized 3PL that absorbs Amazon’s packaging rules, labeling requirements, and shipment logistics so sellers can focus on sourcing and listings. The core services (receive, inspect, label, bag, kit, box, ship) are table stakes. The differentiators are software quality, location relative to ports and Amazon fulfillment centers, pricing transparency, and whether the facility can also run DTC and wholesale from the same inventory. Sellers scaling past a few hundred units per month almost always come out ahead outsourcing prep rather than renting warehouse space and hiring staff.
If you are a brand or seller looking for a prep partner that also connects you to vetted wholesale buyers across independent retail, Amazon sellers, and corporate gifting, Apply to Join Catalist.