Inventory Tracking Amazon Fulfillment: How to Stay In Stock Without Losing Control

Amazon is a sales engine, but it is also an inventory discipline test. If your inventory tracking is sloppy, Amazon will surface it fast through stockouts, suppressed listings, late shipment metrics, and angry customers who expect Prime-like reliability. Inventory tracking Amazon fulfillment is about keeping one truthful view of inventory across inbound shipments, reserved units, sellable units, and everything that is moving through the warehouse.

Brands often assume Amazon inventory is just "send it in and it sells." Then they discover the messy middle. Inventory is in transit, checked in, reserved, stranded, or sitting in your own warehouse while Amazon is out of stock. Meanwhile, your D2C store is selling too, and now channels are competing for the same units. The goal is not to make Amazon simple. The goal is to make your inventory truth stable enough that Amazon does not surprise you.

Why Amazon makes inventory tracking harder than a typical storefront

Amazon adds complexity because it introduces more inventory statuses and more timing risk. Inbound shipments can take time to be received. Inventory can be reserved for orders. Inventory can be stranded due to listing issues. Returns can flow back in ways that do not match your normal process. If you only track a single on-hand number, you will keep making wrong decisions.

The key is to track inventory by status and location across systems, so you know what is actually available to sell, what is committed, and what is delayed. This is the same principle that drives strong warehouse management: inventory truth is not only quantity, it is also where, and what state.

The warehouse has to be the source of truth, or Amazon will amplify bad data

It is tempting to treat Amazon as the center of the world. Operationally, the warehouse is the center of the world because it is where inventory is physically handled and verified. If your warehouse system does not capture inventory moves reliably, you will spend your time reconciling Amazon counts against your own counts, and neither will feel trustworthy.

Bryan Wright, CTO and COO of G10 Fulfillment, described the standard that keeps warehouse truth stable: "A good WMS tracks inventory through the warehouse at every point that you touch it." That matters for Amazon because inventory is constantly moving between inbound, storage, pick, pack, and outbound. If the WMS is not tracking every touchpoint, you cannot maintain a clean record of what you actually have available to allocate to Amazon, and when.

Bryan also gave a vivid example of what deep tracking can look like when inventory stays visible even during movement: "At any point in time, I know that Bobby has this product on fork 10 right now, and if I needed to go find that product, I just got to go find Bobby on fork 10." That kind of visibility matters when Amazon demand spikes and you need to locate product quickly for a replenishment shipment or a channel reallocation.

Scan-based execution is what keeps Amazon allocations honest

Amazon planning is only as good as your inventory data. If inventory moves without scans, the system cannot update in real time, and your allocations will be wrong. That leads to two painful outcomes. You either starve Amazon and lose sales, or you overcommit inventory to Amazon and short your D2C channel.

Connor Perkins, Director of Fulfillment at G10 Fulfillment, described the baseline that makes allocation decisions credible: "You want everything to be scanned in the warehouse, nothing done on paper." Paper creates invisible work. Invisible work creates missing transactions. Missing transactions create inventory drift, and drift is what turns Amazon replenishment into a guessing game.

Connor also described the cost brands pay when execution is weak. They were "losing money by shipping wrong items or wrong quantities of items." For Amazon, wrong shipments and wrong labeling can trigger compliance issues and extra costs. For your own D2C business, those errors create returns and replacements. Scan-based execution reduces both by making picks and packs verifiable.

Inventory status is the secret to avoiding Amazon stockouts and D2C oversells

Amazon inventory planning fails when you treat all inventory as equally available. Inventory that is in receiving is not the same as inventory in a pick face. Inventory allocated to a retailer PO is not the same as inventory available for Amazon replenishment. Returns inventory is not the same as new inventory. If your systems cannot separate those states, you will keep promising inventory that is not actually usable.

This is also why real time matters. If inventory is being picked for D2C orders, your available-to-allocate inventory is shrinking. If your Amazon shipment is being built, your available inventory is shrinking. Real time tracking helps you adjust before you oversell in one channel or miss replenishment windows in another.

Omnichannel pressure is what makes Amazon tracking a business-wide problem

Most brands selling on Amazon are not only selling on Amazon. They are also selling on Shopify, wholesale, or retail. That means a single pool of inventory is serving different commitments. If your inventory tracking is delayed, channels will fight over the same units.

Jen Myers, Chief Marketing Officer at G10 Fulfillment, described the multi-system challenge in plain terms: "You want to make sure your inventory is tracked across those two different systems, to make sure that there's enough inventory." Amazon is one of those systems. Your warehouse is another. If they disagree, you will keep discovering stockouts after they happen.

When tracking is strong, you can allocate inventory intentionally. You can decide how much inventory belongs in Amazon replenishment, how much belongs in D2C, and how much is reserved for wholesale. When tracking is weak, allocation becomes reactive and painful.

Customer visibility reduces the interruptions that cause errors

Amazon is not the only customer. Your own customers still need answers, and your team still needs to plan. When inventory status is unclear, questions become tickets. Tickets interrupt warehouse work. Interrupted work leads to missed scans and errors, which makes inventory less accurate.

Maureen Milligan, Director of Operations and Projects at G10 Fulfillment, described the benefit of real-time access: "What these real-time portals provide our customers is 100% visibility." She also described what that enables: "They can actually watch those progressions going on." When your team can see order progress and inventory movement, they can make better replenishment decisions for Amazon without constantly interrupting the warehouse.

Ship accuracy protects metrics and reduces expensive corrections

Amazon is unforgiving about mistakes. Wrong items, wrong quantities, and messy corrections cost time and money. Strong inventory tracking supports strong execution because it keeps locations truthful and makes verification normal.

Joel Malmquist, VP of Customer Experience at G10 Fulfillment, described an outcome that reflects disciplined execution: "We have over 99.9% ship accuracy of these orders." High ship accuracy reduces the number of corrections you need to push across systems, which helps keep Amazon replenishment planning stable and reduces the churn that creates stranded inventory situations.

How to evaluate a 3PL for Amazon inventory tracking

Ask how the 3PL tracks inventory by status and location. Ask whether internal moves and replenishment are scan-based, not only receiving and shipping. Ask whether you can access transaction history for investigations. Ask how quickly the system can locate product if you need to build an urgent Amazon replenishment shipment.

Bryan described the traceability you should insist on: "We have portals that show you the data. We have history that shows you all of that tracking." That history is what lets you prove what happened when counts are disputed, and it is what helps you diagnose why Amazon inventory and warehouse inventory might diverge.

How G10 supports inventory tracking for Amazon fulfillment

G10 focuses on scan-based execution, transaction-level tracking, and customer-facing visibility so Amazon replenishment decisions are based on real warehouse truth. Connor summarized the baseline: "Having a 3PL and WMS that is 100% scan-based is crucial." Bryan described the tracking foundation behind reliable allocation: "A good WMS tracks inventory through the warehouse at every point that you touch it." Maureen connected visibility to fewer surprises: "What these real-time portals provide our customers is 100% visibility."

If you want to stay in stock on Amazon without losing control of your inventory elsewhere, inventory tracking has to be more than a single on-hand number. It has to be real time, status-aware, and supported by scan-based execution. When those pieces are in place, you can replenish Amazon intentionally, protect your D2C channel, and stop learning about stockouts after they already cost you sales.