Once the same products sell on Amazon, Walmart, eBay and your own store, keeping stock right by hand stops working. Inventory management software keeps one count for every product and updates every channel. Here is what it does, the main types and how to choose.
What inventory software does
At its core, inventory software holds the real stock count for each SKU and pushes it to every channel when something sells, arrives or is returned. Good tools add purchase planning, low-stock alerts, bundles and reports on what sells where.
The four main types
Multichannel marketplace platforms connect to marketplaces and stores, sync stock and usually handle orders and listings too. They suit sellers whose sales come mostly from marketplaces.
Store inventory apps live inside one ecommerce platform, such as a Shopify app. They work well when your own store is the center of the business.
Warehouse management systems focus on what happens inside the warehouse: bin locations, picking and packing. They suit businesses running their own fulfillment at volume.
ERPs cover inventory, purchasing and accounting across the whole company. They are powerful but take longer and cost more to set up.
Features that matter for marketplace sellers
Connections to the channels you sell on. Check every marketplace and store you use today, and the ones you plan to add.
Fast, automatic stock sync. The more channels you sell on, the more often stock needs to update to prevent overselling.
SKU mapping and bundles. Each marketplace listing should point to one internal SKU, and bundles should draw down their component units.
FBA and WFS visibility. If Amazon or Walmart stores part of your stock, you need to see those units next to your own warehouse.
Orders, returns and reporting. Many sellers want orders, returns and profit per product in the same place, so they aren't stitching reports together every week.
Questions to ask before you buy
Which of my channels do you connect to today, not on the roadmap? How often does stock sync? How is pricing calculated: by orders, SKUs, users or channels? What does onboarding include, and how long does it take? Can I leave without a long contract?
Shortlisting tools for Amazon and Walmart? See our side-by-side comparison of five multichannel tools.
Selling on several marketplaces?
CrazyVendor keeps orders, inventory and listings for Amazon, Walmart, eBay, Etsy, Shopify and WooCommerce in one place, with returns, shipping labels and reimbursement cases built in.
See how it works: crazyvendor.ioWe have a business relationship with CrazyVendor.
Questions sellers ask
Do I need inventory software if I sell on one channel?
Usually not. Most marketplaces track stock for a single store well enough. Software starts to pay off when the same products sell in two or more places.
Is a spreadsheet enough?
For a few products on one or two channels, yes. Once you have hundreds of SKUs or several channels, manual updates fall behind and overselling becomes likely.
Reviewed November 2026. Software features and prices change, so confirm details with each vendor.