If you sell regulated, high-value, or warranty-backed goods — electronics, medical devices, cosmetics, anything with a recall or authenticity requirement — "how many do we have" was never enough. You needed to know which one, and where it went. Until now SKU.io tracked quantities but not the individual units behind them. Serial Number Tracking closes that gap — and now follows each unit end to end: opt in per product, capture a serial as stock arrives, choose the exact units when you fulfill, print them on your pick lists and packing slips, and trace any serial's full history.

Adjusting stock used to be a leap of faith. When you removed units — for damage, loss, a recount, or a correction — you couldn't see what that stock was already promised to. Take a few units, and a customer's order could quietly slip into backorder with nobody the wiser. Add stock, and you had no idea which waiting orders it would unblock. Now every inventory adjustment shows its impact before you commit — the exact orders it will fill or backorder — so nothing happens behind your back.

When a product comes in five colours, "Red", "Blue" and "Green" in a dropdown tell you almost nothing — is that red a crimson or a brick? And for anything with a pattern or texture, a word can't describe it at all. Shoppers pick with their eyes, and so do the marketplaces you list on. SKU.io now supports swatches — give each option of a product attribute a colour chip or a small image, and that swatch shows up on your variant products and flows out to the channels that support variant swatches, like Walmart and Shopify. No more guessing which "Red" is which.

Shopify's profit and margin reports are only as good as the Cost per item you enter on each product — and that number goes stale the moment your costs change. Keeping it up to date by hand across a whole catalog is tedious, easy to forget, and the reason so many Shopify profit reports quietly drift out of line with reality. SKU.io now syncs your costs to Shopify for you. Turn on Cost Sync for a Shopify store and SKU.io pushes each mapped product's real average cost into Shopify's "Cost per item" field — so Shopify's own profit reports, and any margin app that reads that field, finally show the truth.

When your FBA inventory hits zero, the ASIN goes dark: the Buy Box disappears, rankings decay, and sales stop until your next shipment checks in — often weeks later. The standard workaround is a "backup" merchant-fulfilled offer on the same ASIN, but keeping it live all the time means it can steal the Buy Box while FBA still has stock, and zeroing it in and out by hand doesn't scale past a handful of SKUs. FBM Backup Mode automates the whole dance: SKU.io publishes 0 to your merchant-fulfilled (FBM) listing while a linked FBA offer still has sellable stock, then publishes the real quantity the moment FBA runs out — and re-suppresses it automatically when FBA is replenished. Your offer never flips fulfillment type and never leaves the ASIN; it just waits its turn.

If you sell on Magento 2 (Adobe Commerce), keeping your store and your inventory system in agreement has meant CSV exports, copy-paste order entry, and stock levels that drift out of date the moment they're published. The new Magento 2 integration connects your store to SKU.io as a first-class sales channel: orders, products, customers, and transactions flow into a dedicated workspace, SKU.io sales orders are created from Magento orders in bulk or automatically, and on-hand quantities push back to your store's inventory sources on a schedule.

Until now, listings only ever flowed into SKU.io. To actually put a product up for sale you still had to log into each channel's seller portal — eBay Seller Hub, Shopify admin, Amazon Seller Central, Walmart — and re-key the same title, description, images, price, and attributes, once per channel. And because every marketplace requires different fields per category, you often didn't discover a missing attribute until the channel rejected the listing.

Multichannel Listing & PIM closes that gap. SKU.io now doubles as a Product Information Management hub that can publish new listings to and update existing listings on every connected sales channel — so your catalog is the single source of truth and each channel stays in sync with it.

Real business relationships are never one person. Your supplier has a sales rep who quotes, an AR specialist who chases invoices, and a shipping coordinator who books freight — but until now, SKU.io gave you a single "contact name" field and left the rest to sticky notes and inbox archaeology. Contacts replaces that flat field with a full contact book on every supplier, customer, and warehouse: unlimited people, each with a role, email, phone, title, and notes, one of them starred as the primary. Contacts show up right in your supplier, customer, and warehouse lists, flow through import and export like any other data in SKU.io, and their personal details are encrypted at rest.

Every merchant that sells online lives with returns, and the awkward ones are the blemished and open-box items: a watch comes back with a scratched bezel, you can't sell it as new, so it drifts into a corner and quietly loses value until someone finally gets around to listing it somewhere. That "someone" was a job — a person opening each product, writing a listing, setting a price, and babysitting it. Automatic eBay listing for blemished SKUs hands that whole job to SKU.io. The moment a return is received and marked as a new blemished SKU, SKU.io can publish it to eBay as an auction — with the item's condition written into the listing — and then keep relisting it, stepping the price down on a schedule you choose, until it sells.

If your fulfillment lives in a third-party warehouse, your operational truth lives in someone else's system. Orders get shipped in the WMS, inventory moves in the WMS, returns land in the WMS — and SKU.io only finds out if someone re-keys it, or if you commissioned a bespoke integration for that one provider. Switch 3PLs, add a second warehouse, or work with a partner running a different platform, and you start over. The new Trackstar integration removes that per-provider tax. Trackstar is a unified API that sits in front of dozens of warehouse systems — ShipBob, ShipHero, Extensiv and more — so a single connection in SKU.io keeps your orders, inventory, products, inbound shipments, returns, shipping methods and bills in sync no matter which WMS is actually doing the work.