Add a marketplace to your existing eCommerce store

Open your catalog to third-party vendors without rebuilding the store that already works. Keep your stack, your code, and your margins.

Two hard ways to add third-party selling to your store

Replatform onto a SaaS marketplace

Rebuild what already works, rent the engine, and give up a share of every sale. Your per-country rules and roadmap move to the back of someone else's queue.

Bolt it on with plugins and custom code

Payouts, split payments, settlement, BuyBox, returns, and disputes – each one becomes yours to maintain the moment traffic grows.

Add a parallel marketplace layer next to your first-party store

Mercur adds marketplace functionality, while your core commerce engine stays untouched. You add third-party selling on top, on infrastructure you control. No migration and no replatforming.

Zero GMV fees

The license is your only platform cost. Your success isn't taxed.

Own the source

Open source, full source for licensees – an engine you can read, audit, and extend.

Your infrastructure

Any cloud, on-premise, or air-gapped. Data residency is your decision.

80% already inside

You customize the last 20%. Upgrades never overwrite your work.

Your storefront

StorefrontProductsBrand

CartCheckoutCustomers

Mercur

Third-party vendorsOffers & BuyBoxPayouts

Shared layer

You bring your own vendors – the suppliers and partners you already work with. No network to rent, no marketplace to share.

What changes in your store once you add a marketplace?

With Mercur, product pages show competing offers, one checkout covers every vendor, and one customer order becomes a separate order, payment, and payout per vendor.

Onboard a vendor

A configurable application, KYC and KYB through your payment provider, and a hard rule: no verification, no payout.

Vendor onboarding, step 1 of 5: the store details form a new vendor fills in before verification

List the catalog

Bulk import by file or API with a mapping wizard. Listings dedupe by EAN, so three versions of one phone become one product with competing offers.

A vendor's product record in the panel: description, media, attributes and the variant table

Win the sale

Offers compete on price and availability. The BuyBox picks the winner and shows every vendor standing behind it.

A storefront product page: two verified vendors offering the same phone, sorted by lowest total price including delivery, with the winning offer selected

Take a mixed cart

One checkout across your own products and third-party offers, with shipping costed per vendor.

One storefront cart split into parcels – two third-party vendors and the store's own – each with its own estimated delivery, under a single checkout

Split the order

The cart breaks into a separate order and payment per vendor, on its own.

The admin order list: one group ID expanding into a separate order per vendor, each with its own payment and fulfillment state

Fulfill and track

Logistics classes, lead times, lockers, and multi-shipment – with a status flow where only the admin marks an order received.

Creating a fulfillment: stock location, shipping method and the line items going into this shipment

Settle and pay out

An append-only ledger, real Pending, Payable, and Paid balances, statements, and invoices. The balance a vendor sees is the money they get.

The settlement ledger for one vendor: Pending, Payable and Paid balances above the ledger movement rows, with statements and payouts alongside

Handle returns and disputes

Per-line returns on your policy window, refunds that match the books, and disputes that hold a payout until they close.

The admin dispute list: each dispute carries its seller, order, reason and state, and the one still open holds the vendor payout

And the part most platforms leave to a spreadsheet: every data export is logged. When someone walks out with the vendor list, there is a record.

How Mercur compares with SaaS marketplace platforms

	SaaS Marketplace	Mercur
Core technology	Closed, vendor-only	Open source (MIT), public
Enterprise code	Black box	Full source for licensees
Integrations	Separate products	Built into one platform
Customization	Tickets and workarounds	Your own layer, official extension points
Deployment	Vendor cloud only	Any cloud or on-premise
Cost model	A percentage of your GMV	Zero GMV fees
Exit	Lock-in	You keep what you paid for
Developer pool	Certified specialists	Any web developer

Built to fit the stack you have

Connect is the integration layer built into the platform on the same login and upgrade path.

Two separate pipelines

Product content and offers sync on separate tracks. A price or stock change goes out the moment it happens, independent of catalog imports.

Errors you can act on

Row-level reports show which row failed and why, while the rest of the import finishes.

AI-native product import

A vendor's file rarely matches your catalog format. The AI proposes the mapping and your vendor confirms it.

Connect the systems you already use

Your ERP, PIM, OMS, and storefront platforms like Magento connect through one framework.

Connect sits at the centre as the hub: the storefront above it, ERP and PIM to either side, and Magento and an OMS below.

Connect is part of Mercur Enterprise.

What the integration process looks like

Four steps, with a team that has shipped marketplaces in production.

Discovery

Map your stack, your 1P and 3P model, and your compliance needs.

Architecture

Design the integration, data residency, and where it runs.

MVP

Stand up the marketplace on one vertical: split cart, commissions, payouts, offers.

Rollout

Onboard vendors and grow.

Questions procurement will ask

Straight answers, in the order they come up.

See how leading brands build their marketplace

Talk to the team behind Mercur – how it works, how other brands build with it, and where it fits for you.