Amazon Seller Flex (FBA Onsite): How It Works, Who Qualifies, and What It Costs

Most sellers on Amazon know FBA. Fewer know Seller Flex.

Amazon Seller Flex is an invite-only program where sellers keep inventory in their own warehouse and Amazon picks up and delivers the orders. Eligible listings carry the Prime badge. In the US, the same model goes by FBA Onsite. In Europe, SellerFlex covers heavy and bulky products.

The program isn’t widely advertised. Many sellers only hear about it once their fulfillment setup is already mature. For the right seller, it’s a good trade. You keep the inventory, and Amazon handles the delivery.

Seller Flex is not Amazon Flex. Amazon Flex is a gig program for drivers who deliver packages in their own vehicles. The two share a name and nothing else.

Here is a quick summary before the full breakdown:

• Seller Flex is invite-only and most active in India. The US version is called FBA Onsite, and Europe runs SellerFlex for heavy and bulky goods.
• Sellers without an invite can still earn the Prime badge from their own warehouse through Seller Fulfilled Prime (SFP).
• Sellers store inventory at their own facility. Amazon handles pickup and delivery
• Eligible sellers get the Amazon Prime badge on qualifying listings
• Amazon Seller Flex fees include referral fees and a per-shipment delivery fee. Amazon does not charge storage fees
• The program sits between FBA and FBM in terms of seller involvement
• Amazon Multi Seller Flex is a shared-facility variant of the same program

What Is the Amazon Seller Flex Program

Amazon’s seller flex program is a fulfillment option where sellers store inventory at their own facility and Amazon handles pickup and last-mile delivery. It sits between Fulfillment by Amazon (FBA) and FBM (Fulfillment by Merchant) in terms of seller involvement.

The Core Idea

Seller flex allows sellers to retain control over fulfillment without managing delivery independently. The seller handles storage, packing, and order readiness. 

Amazon’s logistics partners handle everything after pickup. Customers see Prime delivery timelines on eligible listings.

Where It Runs

Seller Flex is most active in India, where Amazon invites sellers based on account health, sales volume, and operational capacity.

Europe runs its own version, SellerFlex, built for heavy and bulky products. EU sellers can apply through a form on Amazon’s site, though applying doesn’t guarantee a place.

In the US, the program was renamed FBA Onsite. Access there still appears to be invite-only.

How It Fits Into a Fulfillment Strategy

The program provides a fulfillment model that works well for sellers who already have warehouse infrastructure. Instead of sending inventory to an Amazon fulfillment center, the seller keeps stock on-site. 

Managing your own warehouse gives sellers visibility over their inventory that FBA does not, making it easier to reduce amazon backorder situations and maintain product availability. The trade off is that the seller takes on more operational responsibility day to day.

What Is Amazon Multi Seller Flex

Amazon Multi Seller Flex follows the same logistics model with one difference. Multiple sellers operate from a shared or co-located facility. Storage space and operational infrastructure are divided across sellers rather than owned by one. 

The fulfillment process and Amazon’s pickup mechanics work identically to standard Seller Flex.

Seller Flex in the US: FBA Onsite

US sellers search for this program under two names. Both describe the same model.

Amazon started testing Seller Flex in the US in October 2017 with fewer than 50 invited sellers. By early 2018, Bloomberg and CNBC reported that Amazon had renamed it FBA Onsite and was recruiting more sellers. Participants ran Amazon’s warehouse management software inside their own facilities.

Amazon has never published a public US program page for FBA Onsite. Only the seller login portal shows up in search. That suggests access is still by invitation, and likely limited. Amazon also uses the FBA Onsite name in Brazil.

For a US seller with a warehouse and no invite, Seller Fulfilled Prime is usually the closer fit. The comparison below shows how the two differ.

How Fulfillment Works in Seller Flex

Seller Flex runs on a pickup model. Amazon comes to the seller. The seller does not ship into a fulfillment center.

Step 1: Order Comes In

A customer places an order. Amazon routes it to the seller’s Seller Flex site. The seller sees it in Seller Central or through the flex app. From here, the clock starts. The pickup window is fixed. Orders need to be packed and ready before it closes.

Step 2: Seller Packs and Labels

The seller picks the item, packs it, and generates the shipping label through Amazon’s warehouse management system. Labels must follow Amazon’s specifications. Any mismatch at this stage causes problems downstream. Good inventory management across all active SKUs is what keeps this step clean and fast.

Step 3: Pickup Happens at the Seller’s Facility

Amazon’s delivery associate arrives at the seller’s warehouse. They scan the package and take it into Amazon’s transportation network. From this point, the seller has no further role in moving the order. The scan logs the handoff in Amazon’s system, so both sides can see when the package left.

Step 4: Amazon Delivers to the Customer

Amazon completes delivery. Amazon handles customer communication, tracking updates, and any delivery exceptions. The seller does not manage any of this.

Step 5: Metrics Update

Once the order is fulfilled, Amazon updates the seller’s account health data. On-time pickup rate, order defect rate, and cancellation rate all move based on how each order was handled. A missed pickup window or a packing error shows up here. A missed pickup window lowers the on-time pickup rate right away. Repeated misses put Prime eligibility at risk and can trigger an Amazon review of the account.

Amazon Seller Flex vs FBA vs SFP vs Easy Ship

The four programs split the work differently. The real question is who holds the inventory and who moves the box.

Factor	FBA	Seller Flex	SFP	Easy Ship
Inventory stored at	Amazon FC	Seller’s warehouse	Seller’s warehouse or 3PL	Seller’s warehouse
Prime badge	Yes	Yes (when eligible)	Yes, after passing a trial	Limited
Who packs orders	Amazon	Seller	Seller or 3PL	Seller
Who delivers	Amazon	Amazon	Amazon-approved SFP carriers	Amazon
Invite required	No	Yes	No. Open enrollment plus a trial	No
Storage fees	Amazon charges	Seller bears own cost	Seller or 3PL cost	Seller bears own cost
Seller responsibility	Ship to FC	Pack and prep for pickup	Pack, ship, and meet Prime delivery speed	Pack and prep for pickup

FBA 

FBA makes sense for sellers who want hands-off fulfillment. Amazon stores, picks, packs, and ships. The FBA adoption rate helps illustrate how widely this fulfillment model is used. The trade-off is that the seller loses control over storage and pays Amazon’s storage rates.

Seller Flex 

Seller Flex makes sense for sellers who already have warehouse infrastructure and want to retain control over inventory while still accessing Amazon’s delivery network and the Prime badge.

The choice between these programs is a core part of any seller’s fulfillment strategy. For sellers comparing options across such a large marketplace, understanding how many third party sellers are on Amazon can provide useful context. Some sellers use a hybrid approach: keeping standard-size products in FBA while using Seller Flex for big and bulky products.

Those SKUs tend to be bulky items with higher handling needs, or fragile items that need closer oversight during packing. Different product types fit different fulfillment programs depending on size, category restrictions, and margin.

Easy Ship 

It allows Amazon to pick up and deliver from the seller’s location, but Prime eligibility is more limited. It also does not carry the same operational infrastructure requirements as Seller Flex.

Seller Flex vs FBM

FBM (Fulfillment by Merchant) means the seller handles storage, packing, and delivery entirely. There is no Amazon logistics involvement. Seller Flex uses the same seller-side storage model but hands delivery off to Amazon’s transportation network. The result is Amazon Prime badge access and Amazon-managed last-mile delivery. Standard FBM provides neither.

Seller Flex vs Seller Fulfilled Prime

Both programs keep inventory out of Amazon’s warehouses and put the Prime badge on your listings. The difference is who moves the box after it’s packed.

In Seller Flex, Amazon’s carriers pick up at your dock. In SFP, you or your 3PL ship with Amazon-approved carriers and own the delivery promise.

SFP is open to US sellers without an invite. Getting in means passing a trial of at least 100 Prime packages while hitting Amazon’s delivery-speed and tracking targets. Amazon blocks trial graduations during peak, from October 18 to December 31 in 2026. A trial started now finishes in the new year.

Most US sellers who search for Seller Flex already have stock outside FBA and want the badge. For them, SFP is the program they can actually join. AMZ Prep’s Seller Fulfilled Prime fulfillment runs that model for brands that would rather not staff their own warehouse.

Choosing between Seller Flex and Easy Ship

For sellers with strong account health and a proper warehouse setup, Seller Flex offers Prime badge access and better delivery SLAs. Easy Ship is more accessible but carries fewer advantages in terms of Prime visibility.

Sellers with strong logistics capabilities and existing warehouse operations are best positioned to benefit from Seller Flex. For sellers without that infrastructure, FBA or Easy Ship may be a better starting point.

Amazon Seller Flex Eligibility Requirements

Amazon Seller Flex eligibility is not open to all sellers. The program is invitation-based. Amazon evaluates sellers before extending an invite.

The general criteria include:

• Strong account health across order defect rate, cancellation rate, and late shipment rate
• Established sales history on the platform
• Demonstrated ability to handle volume consistently
• A dedicated warehouse or storage facility that meets Amazon’s operational requirements
• Staff availability to manage packed orders within Amazon’s pickup windows
• Barcode scanning equipment and connectivity for Seller Central integration

Infrastructure requirements

Beyond account metrics, sellers need physical infrastructure. A spare room or home storage setup does not qualify. Amazon expects a proper operational environment with space, staff, and process. 

Managing your own warehouse at the required level means consistent staffing, reliable scanning, and the ability to handle volume spikes without missing pickup windows.

Seller rating is also a factor. Amazon looks at overall account standing, not just recent order metrics. A history of strong performance across business operations signals that the seller can sustain Seller Flex’s requirements over time.

Seller Flex for lower-volume sellers

The program is better suited for sellers who already have warehouse operations in place. It requires ongoing investment in space, staffing, and equipment. Very early-stage sellers or those fulfilling low order volumes are unlikely to receive an invite or sustain the operational demands.

Amazon Multi Seller Flex eligibility follows the same base criteria. The difference is that qualifying sellers share a facility rather than operating their own standalone warehouse.

Who Benefits Most from Seller Flex

Seller Flex works best for a specific type of seller. It is not the right fit for everyone.

It suits sellers who:

• Already operate a dedicated warehouse with trained staff
• Sell heavy and bulky products or fragile products that benefit from closer packing oversight
• Want the Amazon Prime badge without sending inventory to an Amazon FC
• Have consistent monthly order volume that justifies the infrastructure investment
• Are building a hybrid approach across FBA and managing your own fulfillment for specific SKUs

It is a poor fit for sellers without dedicated warehouse space, very early-stage sellers, or those with low and inconsistent order volume.

Amazon Seller Flex Fees and Charges

Amazon Seller Flex fees follow a structure similar to other Amazon fulfillment programs, with some key differences.

Referral fees 

Referral fees apply to every order. These are category-based percentages and are the same regardless of whether the seller uses FBA, Easy Ship, or Seller Flex.

Shipping fees 

Shipping fees under Amazon Seller Flex charges are based on the weight and dimensions of the shipment. Amazon applies a per-shipment delivery fee for orders fulfilled through the program. This covers the pickup and delivery service Amazon’s logistics partners provide.

Europe publishes a SellerFlex rate card. Collections need at least 10 units per pickup in the UK, France, Italy, and Spain, and 16 in Germany.

Storage fees 

Storage fees work differently in Seller Flex. Because inventory stays at the seller’s warehouse, Amazon does not charge storage fees. The seller bears their own warehousing costs like rent, utilities, staffing. This can be an advantage for sellers who already have warehouse space and want to avoid Amazon’s storage rate increases during peak periods.

Variable closing fees 

Closing fees may apply to specific categories such as media products. These are charged per unit and are consistent across fulfillment programs.

In India, GST treatment on Seller Flex charges varies by business structure and category. Verifying current tax applicability with a qualified advisor is recommended.

Fee structures across Amazon programs are subject to change. Always confirm current rates inside Amazon Seller Central before building cost projections and stay informed with the latest Amazon Seller Updates 2026 to keep up with fee revisions, policy changes, and fulfillment program updates.

Returns in Amazon Seller Flex

Amazon Seller Flex returns follow Amazon’s standard customer return policy. When a customer initiates a return, Amazon manages the customer-facing communication and the return authorization process.

Returned items are sent back to the seller’s facility. They do not go to an Amazon fulfillment center. The seller receives the returned inventory and is responsible for inspecting it, determining whether it is sellable, and restocking or disposing of it accordingly.

This creates both an operational task and a tracking requirement. High return rates in Seller Flex affect account health metrics the same way they do in FBA. Order defect rate includes customer complaints, A-to-Z claims, and chargebacks. Return patterns can push all three up.

Sellers operating under Seller Flex need a process for handling inbound returns. This includes a physical inspection workflow, a disposition decision, and a restock or removal step. Without it, returned inventory accumulates without visibility and can create operational bottlenecks.

How to Join Seller Flex

In India and the US, there’s no open application. Amazon picks candidates from internal data and sends invitations through Seller Central. Europe works differently. EU sellers with qualifying heavy and bulky products can apply through Amazon’s SellerFlex form.

Sellers can check the Growth Opportunities section of Seller Central and watch for notifications from their account team.

The Seller Flex site within Seller Central is where program details, onboarding steps, and invite status are communicated once Amazon has identified the seller as a candidate. If an invite appears, it typically comes with instructions on next steps and a timeline for onboarding.

Amazon doesn’t publish Seller Flex thresholds. Its standard account health targets are a sensible floor:

• Maintain an order defect rate under 1%
• Keep late shipment rate low
• Keep pre-fulfillment cancellation rate under 2.5%
• Build consistent monthly sales volume
• Have warehouse space and staff ready to operate at Amazon’s standards

Once an invite arrives, Amazon will assess the facility before activating the account. Being operationally ready at that point speeds up the process significantly.

To receive an invitation, there is no shortcut. Amazon uses internal performance data to identify candidates. Maintaining clean metrics consistently over time is the most reliable path.

If the invite does not appear in Seller Central, sellers can contact Amazon through Seller Support. Amazon support can confirm eligibility status and advise on what account improvements may be needed before the program becomes available.

One clarification worth noting: Amazon Flex is a different program entirely. The Amazon Flex program is a delivery driver program for individuals who deliver packages using their own vehicle. Drivers accept delivery blocks through the flex app. Seller Flex and the Amazon Flex program are separate with no overlap.

Seller Flex and the Prime Badge

Yes. Sellers approved for Amazon Seller Flex can display the Prime badge on eligible listings.

Prime eligibility through Seller Flex is tied to delivery performance. Amazon monitors on-time delivery rates and order quality. Sellers who consistently meet Amazon’s thresholds maintain Prime status on their listings. Those who fall below the required rates risk losing Prime eligibility on their Seller Flex orders.

The Prime badge carries real conversion weight. For sellers whose product categories see high purchase intent from Prime members, maintaining that badge is a meaningful commercial advantage particularly in a program that also allows the seller to retain control over their storage setup.

Conclusion

Amazon Seller Flex works when the operational foundation is already in place. A warehouse, a trained team, reliable scanning equipment, and a clean account health record, these are not things to build after the invite arrives. They need to be running before Amazon looks your way.

For sellers building a long-term fulfillment strategy, Seller Flex is one part of the picture. Some brands take a hybrid approach: keeping standard-size items in FBA while using Seller Flex for specialty SKUs or heavy and bulky products that benefit from closer handling. The right mix depends on product category, margin, and existing operational capacity.

Sellers without an invite still have a route to Prime from their own stock. Seller Fulfilled Prime is open to US sellers who pass the trial.

If Seller Flex is on your radar, the most productive next step is a full account health review in Seller Central. Know where your defect rate, cancellation rate, and late shipment rate sit today. That is the data Amazon will use to evaluate you.

Frequently Asked Questions