Launching on a marketplace is often presented as a commercial formality: open an account, upload your catalogue, collect the money. In practice the subject is technical, and that is where projects go off the rails.
We integrate the APIs of platforms such as Mirakl and Shopify for our clients, and the same difficulties recur from one project to the next. Here they are, so you can anticipate them rather than discover them in production.
A marketplace is a second system, not another shop window
As soon as you sell in two places, you have two possible truths for every piece of information: a price, a stock level, a lead time, an order status. The whole integration effort consists of deciding which one is authoritative, and making the other align with it automatically.
Without that explicit decision, management happens by hand. It holds for a few weeks, then a discrepancy appears: a product sold twice, a promotional price left online. Such incidents cost penalties and reputation on platforms that rate their sellers.
The catalogue, the first point of friction
Every platform imposes its own reference model: categories, mandatory attributes, image formats, units. Your internal catalogue never maps onto it exactly. So a mapping has to be written, maintained when the platform changes its model, and rejected products dealt with.
It is thankless but decisive work: a product refused at import does not sell, and the rejection is often silent if nobody reads the error responses. A serious integration reports those rejections to a human, it does not merely send.
Stock and orders: real time does not exist
No synchronisation is instantaneous. Between the moment stock changes on your side and the moment the marketplace accounts for it, time passes. On slow-moving products that delay is harmless; on high-demand items it produces oversells.
You handle that with safety margins and update priorities, not by hoping for real time. In the other direction, orders coming from the marketplace must join exactly the same path as the others, otherwise your fulfilment splits in two and errors follow.
What the APIs actually allow
Before promising a feature, we check what the platform exposes. The Mirakl and Shopify APIs are rich, but they have limits: capped call volumes, non-editable fields, events that are not notified and have to be polled. Those constraints define what is possible.
That is why we study the API before quoting. An integration that works on day one is not a reliable integration: reliability is decided in error handling, recovery after incidents and edge cases, and that has to be designed from the start.
Frequently asked questions
Do I need an e-commerce site to sell on a marketplace?
Not necessarily, but you do need a source of truth for your catalogue and stock. That can be your business management system rather than a shop. Selling only on marketplaces does, however, leave you dependent on their rules and commission.
How long does a marketplace integration take?
It depends entirely on the state of your data and on what the platform exposes. A clean, structured catalogue changes everything; a catalogue that needs normalising is often the bulk of the work. We assess it after reviewing your data.
Can several marketplaces be synchronised at once?
Yes, and it is common. The difficulty grows less with the number of platforms than with the number of different reference models to maintain. Hence the importance of building one central mapping rather than an isolated integration per platform.