Selling on a marketplace is no longer a side option: it is close to a required step in growing an online business. But you are selling in someone else's shop, under their rules. Here is what you need to master, platform by platform.
Why marketplaces attract so many sellers
Online retail keeps growing, driven by multi-seller platforms that make customers easy to reach and offer visibility that is hard to build alone.
Worldwide, the hundred largest marketplaces handle roughly $3.8 trillion in trade, a market that has doubled in six years. In Europe, marketplaces account for around 70% of cross-border e-commerce revenue, more than €247 billion, with Amazon and eBay taking over half of that.
Three things explain that growth:
- Ready-made infrastructure: fulfilment, payments and customer service already exist, which lowers the barrier to launching sharply.
- Immediate access to a large audience: millions of daily visitors, already intending to buy.
- Consumer trust: the platform's reputation reassures, particularly buyers who do not yet order from independent shops.
That growth should not hide the competition. Marketplaces attract thousands of sellers, from sole traders to international brands. Those who do not learn the rules, do not optimise their listings or ignore each platform's requirements simply miss out.
What to understand before you start
Many sellers start with good intentions but no grasp of the rules. That explains most of the early exits.
On your own e-commerce site you keep control: how products appear, the marketing, the customer relationship, the terms of sale. Selling on a marketplace means joining an existing ecosystem with its own conventions and constraints.
A marketplace is not your website. You are selling in someone else's shop, under rules you need to know inside out.
Amazon, Leroy Merlin, Decathlon: three different logics
Amazon: the shared listing
On Amazon, products are grouped onto a single listing. Several sellers can offer the same item, which means you do not fully control the product page. Visibility then depends on price, fulfilment performance, account history and customer service quality. Selling well on Amazon starts with understanding those mechanics.
Leroy Merlin: your own listing, within a frame
The model differs. Each seller usually has their own listings but must respect a strict framework on content, technical data and compliance. Integration is more technical; in exchange the presentation is more your own.
Decathlon: selection at the door
The approach is more selective still. Entry follows an approval process with high expectations on product quality, fulfilment and brand image. It is less about volume and more about partnership.
Rules, commissions and constraints
| Platform | Indicative commission | Fulfilment | Watch out for |
|---|---|---|---|
| Amazon | roughly 12 to 15% by category | Seller, or delegated to Amazon | Shared listing, price war |
| Leroy Merlin | roughly 14% by category | Seller | Product data quality, deadlines |
| Decathlon | variable, negotiated | Seller | Approval process, compliance |
These rates are indicative: they vary by category and change regularly. Always check the current schedule when you apply.
Beyond costs, every marketplace enforces precise performance metrics. A poor response rate, late deliveries or sloppy returns handling degrade visibility quickly and can bring penalties on the account.
Is your catalogue ready for these three platforms?
We audit your catalogue and your logistics constraints, then hand back a prioritised list of marketplaces with the preparation each one needs.
Request a free auditWhy many sellers give up too soon
Every year plenty of sellers open an account, list a few products and then stop. In most cases the problem is not a lack of opportunity but a lack of method.
Many assume the marketplace will generate sales by itself. They meet a harder reality: fierce competition, listings nobody sees, margins that were never properly calculated and complex rules. Without structure the first results are slow, and discouragement follows.
The six skills you need together
Running a marketplace account means doing several jobs at once. That is what beginners discover too late.
- Account management: configuring the seller account, whether Seller Central or a retailer's dashboard, tracking the required metrics and following the rules to avoid penalties.
- Listing creation and optimisation: titles, attributes, bullet points, images and enhanced content, following the structure each category expects.
- Search visibility: understanding each platform's internal engine, which does not follow Google's rules, and working the keywords that actually convert.
- Fulfilment and order handling: syncing stock, meeting the delivery times you promised, handling returns without wrecking your metrics.
- Customer service and disputes: replying within the required time, defusing before escalation, documenting every incident.
- Margin analysis: working out net margin per SKU, commission and fulfilment included, so you know what to push.
Why it is hard alone
None of these skills is impossible on its own. The difficulty is holding all six, and the fact that a weakness in any one of them blocks everything else.
Training and support
I came across marketplaces in 2022, at a company selling a wide mix of products: kitchen timers, foot warmers, wheelbarrows. That variety taught me one thing above all: marketplaces are open to every kind of seller, but working them demands method, rigour and an understanding of each platform's own rules.
Today we support and train:
- independent sellers launching on marketplaces;
- companies wanting to structure or improve their sales;
- people changing career who want the skills to work independently.
The approach is deliberately cross-platform. Whichever one you sell on, the objective is the same: understand how marketplaces work, structure the seller accounts, improve product visibility and make the business durable.
This is not theory. It addresses concrete problems: learning the dashboards and the rules, structuring an account, creating and optimising listings, reading performance, laying foundations you can build on. The work happens on your catalogue and your real platforms, not on generic screenshots.
Taking your marketplace project further
Whether you are launching or professionalising, the goal is to give you what you need to sell methodically while staying independent.
Want training to sell on Amazon, Leroy Merlin, Decathlon or other marketplaces, or to structure your team's work? Let's talk. The first conversation takes thirty minutes and commits you to nothing.