The most complex online commerce systems
Advanced custom commerce is not “just a storefront”—it orchestrates many suppliers, pricing rules, cross-border tax and logistics in real time when packaged SaaS stops matching how you actually sell.
Off-the-shelf SaaS and open-source stacks cover many shops well. A different conversation starts when business rules, legal, finance and logistics must work together under heavy load — that is where custom software in MACH architecture (microservices, API-first, cloud, headless) usually wins.
Below are five classes of systems we build as custom work: from marketplace engines to multi-tenant SaaS. Each page explains scope, risks and how we typically compose the stack (Next.js, MedusaJS, NestJS, PostgreSQL, event-driven integrations).
Full service: headless & B2B commerce
Complex commerce archetypes — five system types
Multi-vendor B2B marketplace
Many suppliers, one platform: company hierarchies, contracts, split checkout, trade credit and financial integrations.
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CPQ & product configurators
BOM rules, configuration validation, live pricing from commodities, quotes and outputs for production.
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Cross-border composable commerce
OMS, multi-warehouse routing, VAT, duties and restrictions in real time behind headless storefronts.
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Quick commerce & dark stores
Real-time inventory and cart, warehouse geofencing, courier dispatch and scaling for demand spikes.
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Multi-tenant SaaS commerce
A “store factory”: data isolation, shared codebase, strict SLAs for drops and traffic surges.
Read moreFrequently asked questions
- When should you choose custom ecommerce instead of Shopify or Magento?
- When your model needs many suppliers in one cart, deep B2B pricing and contracts, CPQ with BOM, live cross-border tax and duties, or realtime geofencing like quick commerce—packaged SaaS often cannot encode that logic without expensive workarounds.
- What is split checkout in a B2B marketplace?
- It splits one customer order into fulfilments, payments and settlements per supplier—while keeping a single buyer experience. That needs a coherent order core, finance integrations and usually event queues.
- What does MACH architecture mean for ecommerce?
- MACH is microservices, API-first, cloud and headless: a storefront (e.g. Next.js) separated from order engines and domain services (e.g. NestJS, PostgreSQL) that you can swap and scale independently.
- How is this cluster different from your headless & B2B commerce service page?
- Our headless commerce page covers the broad practice of storefronts and ERP/PIM work. Here we focus on the hardest shapes: multi-vendor marketplaces, manufacturing CPQ, OMS-heavy cross-border, quick commerce and multi-tenant SaaS—with emphasis on backends and integrations.
- Do you always use MedusaJS?
- No—MedusaJS is a strong fit where the commerce layer matches the product. For extreme marketplaces, CPQ or multi-tenancy we often extend or replace parts with dedicated NestJS services and a relational core.
Content last updated: March 18, 2026
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