An operations and growth partner for Amazon-first US brands

Amazon-first brands tend to look alike from the inside. Amazon brings in most of the revenue. Operations run on spreadsheets, four or five SaaS tools and a couple of virtual assistants, and someone senior still reconciles stock, fees and ad spend by hand before each reorder. This page is for those teams. It covers where the money usually leaks and which Seller Central report shows each leak, what changes when you add channels, and what you keep when we build the system that closes the gaps.

Is this page for you?

It is if a founder or head of ecommerce owns the numbers, Amazon is most of the revenue, and the next stage means more channels on the same small team. The page is written for US brands selling on US marketplaces, and the 20+ marketplaces we have shipped integrations for include Amazon, Walmart, Shopify, eBay, TikTok Shop, Target Plus, Wayfair, Etsy and Temu. If one of the lower rows in the table sounds more like you, another option is the better fit, and we would rather say so now. If Shopify, not Amazon, is where most of your revenue lands, start with what we build for Shopify brands.

Run a Shopify-first brand, an Amazon agency or a 3PL instead? Who we help has a page for each.

Where do Amazon-first brands usually leak revenue?

Most leaks already show up in reports Amazon gives you. The trouble is that nobody opens ten reports every week and compares them. Most of the reports below sit on the fulfillment reports page in Seller Central (Reports, then Fulfillment), and Amazon's list of FBA business reports (checked September 25, 2026) describes each one. Work down the table once a month and you will know where the money goes before you pay anyone to fix it.

The Amazon-first leak checklist

Three rows have deadlines. Amazon's Restock Inventory report marks a SKU as low stock when its days of supply is less than your lead time, and says that by then orders from your supplier may need to be expedited, so treat the report's recommended ship date as the earlier signal. The stranded inventory report page says units with no listing or removal order within 30 days of Amazon's notice are designated unsellable. For units lost or damaged in a fulfillment center, the claim window is 60 days from the day the loss is reported in the Inventory Ledger report or the Inventory Defect and Reimbursement portal (all checked September 25, 2026).

Two rows are fees you may already be paying. The FBA Inventory report estimates the aged inventory surcharge for each age band on the next charge date, and shows whether the Low-Inventory-Level Fee applied in the current week. The Fee Preview report lists the size tier, dimensions and weight Amazon uses to estimate your FBA fees, from data that can be up to 72 hours old (both checked September 25, 2026). If that size tier is bigger than your own measurements support, the higher fulfillment fee can apply to every unit Amazon ships until the measurement is corrected.

When Amazon does pay, check the amount. Its FBA inventory reimbursement policy pays the sourcing cost for sellable units lost or damaged before a customer orders, up to $5,000 per unit. If you have not entered your cost on the Manage Your Sourcing Cost page, Amazon uses its own estimate instead. The Reimbursements report itemizes each reimbursement with its reason and amount per unit, so you can compare every line with what the units cost you (both checked September 25, 2026).

Three rows decide whether shoppers see you. Amazon's suppressed listings page says customers cannot find a suppressed listing in search. Its Becoming the Featured Offer page says an out-of-stock offer cannot become featured, and that Business Reports show your Featured Offer percentage. The Amazon Ads FAQ adds that a Sponsored Products ad does not display when the product is out of stock or is not the Featured Offer. Spend on a SKU already below its lead time pulls the stockout closer, and then the ad goes dark anyway. Amazon's Sponsored Products guide names the Advertised product report, where that spend shows up; read it next to Restock Inventory (all checked September 25, 2026).

How we automate the checklist. The software we build requests the same data through Amazon's Selling Partner API. Amazon's FBA report types include GET_RESTOCK_INVENTORY_RECOMMENDATIONS_REPORT, GET_FBA_INVENTORY_PLANNING_DATA (with the same aged-inventory and low-inventory-level fields), GET_LEDGER_DETAIL_VIEW_DATA and GET_FBA_REIMBURSEMENTS_DATA. Its analytics report types add GET_SALES_AND_TRAFFIC_REPORT, which carries buy box percentage by date and ASIN and needs the Brand Analytics role (checked September 25, 2026). Those four FBA reports can only be requested, not scheduled, so the system requests them on its own timetable and keeps every copy. That matters because the Inventory Ledger holds 18 months of history, and your own copy can go back further.

To put a dollar figure on the first row, use the stockout cost calculator. It multiplies average daily units by days out of stock and unit contribution margin, adds any ad spend that kept running, and tells you which Seller Central report each input comes from. The result is an estimate from your inputs, and nothing you enter is stored or sent. The full set of problems, with how to fix each one, lives under operations gaps.

What changes when you add Walmart, TikTok Shop or Target Plus?

Every new channel brings its own catalog rules, stock feed, order flow and scorecard, and all of them draw on stock your Amazon buyers also need. The table sums up what three common next channels ask of an Amazon-first operation, from each company's own pages (checked September 25, 2026), and what your system has to add to keep up.

The stock is shared across every channel, and on Walmart and Target Plus running out or shipping late counts against you. One catalog, one stock position across FBA, 3PLs and your warehouse, and one order flow turn each new channel into a configuration job rather than a new team. Our marketplace expansion service covers which channel to add first, the marketplaces hub has a guide per channel, and our AI agents take on the routine work across them. For the staffing side, read running more marketplaces with the team you have.

Why pay anyone when Amazon's new tools are free?

It is a fair question, and sometimes the answer is that you should not. On September 24, 2026, Amazon announced multichannel selling tools in Seller Central (checked September 25, 2026). At launch they connect eBay, Shopify, TikTok and Walmart accounts, import and link those listings, show multichannel sales and orders, and fulfill across channels. Amazon says the tools will roll out gradually to sellers in the US store over the coming months, at no additional cost. If you sell on Amazon plus one of those channels and your stock sits at Amazon, start there. It may be all you need, and trying it costs nothing.

Then look at where your operation goes beyond that list. Target Plus is not among the first four channels, and Target's rule against competitor fulfillment services means its orders ship from outside Amazon's network. Amazon's announcement also does not mention stock held at a 3PL or in your own warehouse, purchase orders to suppliers or an ERP. If those are part of how you run, you need a system that sees all of them and follows rules your team sets. Our breakdown of the new Seller Central tools tracks what they cover at launch and what Amazon has only announced.

An accelerator, an agency or an owned system: what do you keep?

The three common ways to get outside help leave different things with the brand. A reseller accelerator buys your stock and sells it. Pattern's 3P Accelerator page says "We purchase your inventory upfront", that Pattern then handles ads, content, fulfillment and customer service, and that brands set the strategy and have the final say on major decisions (checked September 25, 2026). Pattern resells the stock, so the retail sale is Pattern's and the brand is paid for its inventory. If you would rather sell wholesale and hand off the channel, that is the better choice; our comparison with Pattern explains its 3P and 1P models.

A full-service agency works inside your accounts and bills for people and time. The accounts stay yours, but the work stops when the contract does, and reports built in the agency's own tools may leave with it. An owned system works the other way round: the software runs on your own accounts, your team sets the rules, and the next section lists exactly what stays yours. The five-model comparison sets out who keeps the seller role, the margin, the data and the ad account in each model.

What do we deploy, and what stays yours?

Ecomsellertool is a tech agency that helps Amazon-first US brands close the operations gaps that leak revenue. We deploy Ecomsellertool Growth OS on your own seller and ad accounts, build the custom modules and AI agents your operation needs on top, and connect new channels to the same system. Routine actions run within the rules you approve, and your team makes the calls that matter.

Growth OS is the base: listings and catalog sync, orders and shipping, inventory and replenishment, 3PL reconciliation, margin-aware advertising, FBA reimbursements and reporting. Custom work covers what is specific to you, such as a supplier feed, the 3PL you already use or an agent that drafts purchase orders for approval.

We tell you which steps follow fixed rules and which use a model. Reorder points, claim windows and ad spend caps are rules your team sets. A model does the work rules handle badly, such as forecasting demand from noisy sales history, reading supplier emails and invoices, and drafting the note that explains each alert; each agent page lists its rule steps and model steps. Purchase orders, budget changes, reimbursement claims, appeals and customer replies come back to a person on your team, with the evidence and a proposed next step.

What you keep

In one sentence: You keep your accounts, your data and the custom code we build; the Growth OS base is licensed to you. The exit terms are just as plain. Your accounts, data and custom code stay with you; the Growth OS base continues under its license terms. For how we license software today, see the single-company license terms we use for our white-label products.

What have we built for brands like yours?

For Truskin, a skincare brand selling across several marketplaces, we built a custom Amazon advertising and reporting portal. It connects the Selling Partner API and the Amazon Ads API, builds dashboards from any field in the reports, and refreshes the last 60 days of data because Amazon restates figures daily. It also maps campaign ASINs for Sponsored Brands and Sponsored Display, so spend and sales land on the right product, and lets the team tag campaigns by intent, such as branded, defense or conquesting.

For Lavley, a gifting brand, we built a sales analytics and goal-setting suite on Amazon data. It combines listings, FBA inventory, orders, finance and advertising reports, and lets the team enter cost of goods with a history of every change, so profit is calculated from real costs. Goals are set by brand and product type for units, gross revenue, net profit and net margin, and analytics run by brand, ASIN, year, quarter, month and week.

Both systems read the brand's own seller and advertising data through Amazon's APIs. Across all our work, we have built on Amazon's seller APIs since 2017, shipped 50+ tools, served 100+ teams and built integrations for 20+ marketplaces. About us explains who we are and how we work, and brand facts lists the facts we publish about ourselves.

What does it cost, and how do you start?

The first step costs nothing. For the free 24-hour diagnostic you leave your email, we send you a Login with Amazon link, and you approve access on Amazon's own page, with no password shared. Within 24 hours of connecting, on business days, we email a report of what is going wrong in the account, with a dollar estimate where the data supports it. We only read data; we never change listings, prices, stock or ads. The report is yours whether or not you work with us.

After that, you pay for the build. We scope custom modules and agents in an architecture doc with a fixed price and go-live date, and the Growth OS base is licensed to you on terms agreed before the build. We do not publish a price list, because the price depends on how many channels, warehouses and custom modules your operation has. To weigh the cost against payroll, see Growth OS against an in-house team, which uses US wage data from the Bureau of Labor Statistics.

1. Diagnose. Connect Amazon for the free 24-hour diagnostic, or upload reports for the Quick Scan if you would rather not connect.
2. Scope. On a call, we pick the gaps worth closing first and write them into the architecture doc, with a price and a go-live date for each module.
3. Deploy. Growth OS goes live on your accounts, and custom modules and agents follow on their dates.
4. Add channels. Walmart, TikTok Shop or Target Plus connect to the same catalog, stock position and order flow.

Prefer to talk first? Schedule a call from the card below with the people who build the systems.