Every marketplace wants your products described its own way, in its own format, refreshed on its own schedule. Maintaining four separate product lists is how prices drift, titles go stale, and out-of-stock items keep selling on a channel you forgot to update. The fix is one catalog that feeds every channel — so you edit an item once and it is right everywhere. Here is how it works, and why it matters more than the channels themselves.
What is a product feed?
A product feed is your catalog expressed in the exact shape a destination expects. Your online store publishes a live feed URL that Google Merchant Center (for Google Shopping) and Meta Commerce Manager (for Facebook and Instagram) read; for the Amazon and eBay marketplace channels, Amazon Seller Central and eBay take a flat file formatted to their spec. Get the format wrong and listings are rejected; keep it in sync and your inventory and prices update on the channel’s own schedule without you touching it again.
How does one catalog reach all four?
From a single product list, Retailer OS generates each one in the right format:
- Google Shopping and Meta (Facebook + Instagram) — a product feed your online store publishes at a live URL; paste it into Google Merchant Center or Meta Commerce Manager and it re-fetches on a schedule. It comes with the online store: a feed, not a marketplace channel or a separate add-on.
- Amazon Seller — a flat file (TSV) formatted to Amazon’s spec, ready to upload.
- eBay — a File Exchange CSV.
- Per-channel title overrides for the platforms that want different copy, with each platform’s character limits respected.
Because the feeds are generated, not hand-built, the schema stays honest — tabs, newlines, and carriage returns are escaped per each spec — so listings are not rejected for a stray character. That reliability is the unglamorous part that actually keeps you selling.
Why does one source of truth matter?
Because the alternative is four lists slowly disagreeing. When every feed comes from the same catalog that runs your store and your online shop, a price change or a stock update happens once and propagates everywhere. No re-keying, no channel quietly selling something you no longer have, no Sunday spent reconciling. This is the same connected-system principle that makes multi-channel retail sustainable instead of a second full-time job.
Where should you start?
Start where your customers already are. If they find you through search, get your online store’s Google Shopping feed clean first; if you want marketplace reach, add Amazon or eBay. Each marketplace channel is an add-on ($99.99/month) rather than a rebuild, so you can grow one at a time; see how that is priced on the pricing page, and what else connects on the integrations page.
You should not manage four catalogs for four destinations. Manage one, and let each marketplace and feed get it in the format it wants. See the platform →
Last updated July 15, 2026