Case
One stock figure for the warehouse, the website and the marketplaces
Every channel takes quantity and prices from one source, and a discrepancy becomes an error you can see rather than a normal part of the work.
≈ an approximate estimate of my actual process
Before
At first the current stock figure lived in the accounting system. It reached the website and the marketplaces separately, partly as files: when Rozetka and Prom, the two big Ukrainian marketplaces, were added, listings, prices and quantities were uploaded there once a day, at best.
Because of that, between a sale and the channel's update there was a window in which the marketplace still allowed someone to buy what was already gone. What follows is either a call saying "sorry, we have run out" or a cancellation, and a cancellation damages the seller's rating.
The alternative was just as bad — deliberately understating the available stock "just in case" and not selling what is actually there.
Prices lived their own separate life: one figure in the price list, another on the website, a third on the marketplace, because the files were uploaded on different days.
How I automated it
The accounting system became the source of quantity and price.
Changes are passed to the channels. Reservations are counted too, so the same unit is never available for two orders.
If a channel did not accept the update, the system reports an error — no answer does not count as a successful sync.
A new channel is connected the same way: its price and availability rules are described separately, and the source stays the same.
After
The quantity in the warehouse, on the website and on the marketplaces is the same. Files remain as a fallback rather than as daily work.
What it gave
Selling stock that does not exist, and holding stock back by hand, stopped being a normal part of the process.
Nobody has to prepare daily files any more, and a sync problem is visible as an error of its own before a customer runs into it.
What would be different in your company
A channel can be a website, Rozetka, Prom, another shop or a partner's warehouse. What is needed is a workable way to exchange data — an API, a feed or another supported interface.
Each channel can have its own rules: the full stock, one particular warehouse, or a reserve buffer.
Show me a similar processTechnical details
Python, accounting system API, website and marketplace APIs, an update queue, failure alerts