Short answer: Good Amazon FBM inventory management means every order moves through one connected chain: the order arrives from Amazon, it is checked against real stock, any shortfall triggers a purchase, purchased goods are received and counted, and the order is picked, packed and shipped with tracking sent back to Amazon. When those steps live in separate spreadsheets, stock counts drift, orders wait for someone to notice them, and profit becomes a guess. When they live in one system connected to Amazon's data, each step updates the next automatically.
This guide walks through that chain stage by stage, explains where spreadsheets usually break, and introduces HutsyBoard, the marketplace-to-warehouse platform we built for this workflow.
What FBM means for your operation
With Fulfilled by Merchant (FBM), you, not Amazon, store, pack and ship the orders. Amazon's FBM page also lists your responsibilities after the sale: using Buyer-Seller Messaging for customer service, and responding to return requests within 24 hours.
Amazon tracks how well you do this. Its FBM guidance points sellers to the Account Health dashboard, where you can monitor rates for order defects, late shipments, pre-fulfillment cancellations and valid tracking. Amazon sets the targets for these metrics and can change them, so check your own dashboard for the current numbers.
In practice, almost every one of those metrics comes back to operations:
- Late shipments happen when orders sit unnoticed or stock is not where the system says it is.
- Pre-fulfillment cancellations happen when you sell units you do not actually have.
- Missing or invalid tracking happens when shipping and order records are not connected.
That is why FBM is an inventory and process problem before it is a shipping problem.
Why spreadsheets break down
Spreadsheets are a reasonable way to start. They stop working as soon as several people, suppliers or sales channels are involved:
- They are always out of date. A sheet shows stock as of the last time someone updated it, not as of the last order.
- They do not enforce a process. Nothing stops someone from marking goods as received without counting them, or from buying the same item twice.
- They lose the evidence. Supplier invoices, receipts and photos end up in email threads and chat apps, not attached to the purchase they relate to.
- They hide profit. Unit cost, shipping cost and Amazon fees sit in different files, so true profit per order is rarely calculated, and almost never in time to act on.
None of this is a people problem. It is a systems problem.
The order-to-shipped chain, stage by stage
1. Orders come in from Amazon
Every FBM workflow starts with the order. Amazon provides the Selling Partner API (SP-API), which its developer documentation describes as "a REST-based API that helps sellers and vendors access their data on orders, shipments, payments, inventory, and other business information." Access uses OAuth authorization, so the seller grants a tool permission without sharing Seller Central passwords.
What good looks like: new orders appear in your operations system automatically, with no exports or copy-paste.
2. Orders are checked against stock, and shortfalls are flagged
Each order should be matched against stock you actually have on hand. Anything you cannot fill from current stock is a shortfall, and it needs action today, not at the end of the week.
What good looks like: one view showing which orders can ship now and which are waiting on stock, by SKU and quantity.
3. Shortfalls become purchases, with proof
If you buy from suppliers to fill orders or replenish stock, each purchase should be linked to the need that triggered it. The supplier's invoice or receipt should be attached to the purchase record. This keeps costs accurate, helps resolve supplier disputes, and means invoices are ready if a marketplace ever asks for them.
What good looks like: every purchase has a supplier, cost, quantity, the orders or SKUs it covers, and attached proof.
4. Goods are received and counted
Receiving is where most stock errors begin. If goods arrive and someone types a number into a sheet, mistakes go straight into your stock count. Scanning items at receiving, for example with QR codes tied to the purchase, confirms what actually arrived against what was ordered.
What good looks like: receiving updates stock automatically, and differences between ordered and received quantities are flagged straight away.
5. Inventory stays accurate across channels
If the same warehouse serves Amazon and other marketplaces, stock must reflect all of them. Otherwise one channel sells units another has already sold, which leads to cancellations, and cancellations affect account health.
What good looks like: one stock record per SKU per location, updated by receiving, orders and adjustments, not by memory.
6. Pick, pack and ship
Pickers need a clear list of what to pull, packers need to know what goes in each box, and the shipping step needs to produce a label and send tracking back to the marketplace. Amazon's Buy Shipping service lets sellers buy labels at pre-negotiated carrier rates and, according to Amazon, gives added protection for delivery claims.
What good looks like: each order moves through picked, packed and shipped statuses, and tracking reaches Amazon without manual entry.
7. Profit is measured per order
Once an order ships, you should be able to see what it earned: sale price minus product cost, shipping and marketplace fees. Without this view, you find out which SKUs lose money only after weeks of shipping them.
What good looks like: profit by order and by SKU, built from the same records used to run the operation.
Where HutsyBoard fits
We built HutsyBoard (hutsyboard.com) to run this chain in one place. It is a marketplace-to-warehouse platform for Amazon FBM and multichannel sellers. In plain terms, it covers:
- Amazon connection via SP-API OAuth: connect your Amazon seller account through Amazon's authorization flow rather than by sharing credentials.
- Orders and shortfall: see incoming orders and which ones you cannot yet fill from stock.
- Purchasing with supplier proof: create purchases against shortfalls and attach supplier evidence to each one.
- QR receiving: scan inbound goods so received quantities update stock directly.
- Inventory: a single stock record that orders, purchases and receiving all update.
- FBM pick, pack and ship: move orders through warehouse steps to shipment.
- Profit: see what orders earn, based on the costs recorded along the way.
You can read the full product overview on the HutsyBoard product page.
What software will not do for you
A platform makes the process visible and harder to skip, but it does not replace judgment. You still need reliable suppliers, sensible pricing, enough stock and a team that follows the process. HutsyBoard is an operating tool. It does not promise sales, profit or account health outcomes. Amazon's policies and metric targets can change at any time, and your process should adapt when they do.
Where ECOMHUTSY fits
ECOMHUTSY has run e-commerce operations since 2016. We have processed $150M+ in e-commerce sales and work with 100+ active clients across 50+ countries. HutsyBoard is built around the same operational problems our team of 100+ e-commerce professionals deals with every day: orders that need stock, stock that needs purchasing, and purchases that need proof.
If you want help beyond the software, our Amazon automation and seller services teams can work with you on process design and day-to-day operations. Those services are priced after a consultation.
Frequently asked questions
What is the difference between FBM and FBA inventory management?
With FBA, Amazon stores and ships your products, so you mainly manage replenishment into Amazon's network. With FBM, you manage the whole chain: purchasing, receiving, storage, picking, packing, shipping, customer service and returns.
Can I run FBM from a 3PL instead of my own warehouse?
Yes, FBM only means the seller, not Amazon, is responsible for fulfilment. Many sellers use a 3PL. The same rule applies: stock records and order statuses must stay connected so tracking and counts stay accurate.
Does HutsyBoard need my Amazon password?
No. HutsyBoard connects through Amazon's Selling Partner API using OAuth authorization, which is Amazon's standard way for sellers to grant tools access without sharing login details.
Can HutsyBoard handle channels other than Amazon?
HutsyBoard is built for Amazon FBM and multichannel marketplace-to-warehouse operations. For details on supported channels and setup, see the HutsyBoard product page or ask us during a consultation.
See if it fits your operation
Tell us how your orders, purchasing and warehouse run today. We will walk through where the gaps are and whether HutsyBoard, our services, or both make sense for you.
Amazon programs, metrics and policies change. This article reflects publicly available Amazon information as of October 2026. Always check Seller Central for current requirements.
Sources
- Amazon, Fulfilled by Merchant (FBM): https://sell.amazon.com/programs/fulfilled-by-merchant
- Amazon Developer Docs, What is the Selling Partner API?: https://developer-docs.amazon/sp-api/docs/what-is-the-selling-partner-api
- Amazon Developer Docs, Authorize public applications (SP-API OAuth): https://developer-docs.amazon/sp-api/docs/authorize-public-applications
