B2B ecommerce platform: MedusaJS and Next.js (implementation costs)

TL;DR - Quick summary
- B2B is not B2C: Retail stacks break on contract pricing, credit limits and multi-step approvals. Headless (MACH) architecture fixes that boundary.
- MedusaJS v2 backend: Open-source Node.js commerce core for custom flows without SaaS-style take rates (e.g. Shopify Plus).
- Next.js frontend: Fast panels so wholesale buyers can load huge carts without the browser freezing.
- Delivery certainty: GMI Software is a Polish partner offering fixed-price B2B programmes after DDT (Discovery, Design & Technology).
The problem: your B2C stack blocks wholesale
Leaders often force retail platforms into wholesale reality: carts needing manager approval, ERP-driven price lists - plugins bend until they snap.
Result: 8-second loads, brittle warehouse sync, sales ops retyping orders. With 16+ years and 120+ projects across Poland and Europe, GMI Software recommends a dedicated B2B engine you control.
MedusaJS vs Magento and Shopify Plus
Your core sets operating cost for **five to ten years**:
- SaaS (e.g. Shopify Plus): Strong in B2C. In B2B expect lock-in and fees on large tickets. Deep checkout changes for trade credit are often blocked.
- Monoliths (e.g. Magento): Flexible but heavy to run; upgrades risk the whole stack.
- MedusaJS v2 (GMI’s pick): Headless Node.js, no per-order platform tax, full source control. Modular rules mirror offline procedures.
Why Next.js for wholesale panels
Medusa is the engine; buyers touch Next.js. A 2026 B2B portal pairs ERP-grade logic (e.g. Berg System CRM) with consumer-grade responsiveness (e.g. SFD at 100,000+ downloads and 4.9★).
- Speed: React Server Components and disciplined data fetching keep thousand-row tables snappy.
- Reliability: Long cart-building sessions survive browser hiccups.
- Omnichannel: The same Medusa APIs later power a React Native field app without a second backend.
What does a GMI B2B platform cost?
Enterprise budgets are real, but headless lets you phase delivery:
- Budget: Custom MedusaJS B2B, Next.js console, deep PIM / WMS / ERP APIs - typically PLN 160,000-300,000 depending on rules.
- Timeline: Production MVP usually three to six months.
Cost drift is the fear. DDT maps architecture, data and journeys before code. That is how we can offer a fixed-price guarantee among the few Polish houses that commit that way.
Frequently asked questions
- Why is MedusaJS stronger for B2B than Shopify Plus?
- MedusaJS avoids per-order platform fees that hurt B2B margin and reduces lock-in. As Node.js open source you can reshape checkout for trade credit, deferred invoicing and bespoke approval flows.
- How much does a headless MedusaJS + Next.js B2B platform cost?
- At GMI Software these builds usually fall between PLN 160,000 and 300,000 depending on pricing logic and ERP scope. Free preliminary estimate within 48 hours.
- How do you integrate MedusaJS with ERP (e.g. Comarch, SAP, Subiekt)?
- MedusaJS is API-first. We add dedicated services (e.g. NestJS) that sync stock, contract prices and invoices bidirectionally in near real time.
- Is Next.js suitable for complex wholesale B2B storefronts?
- Yes - the App Router and React Server Components keep heavy tables and large catalogues responsive, avoiding classic SPA jank.
- Do I own the code after GMI ships my B2B platform?
- Yes - after milestones are paid you receive full rights to front and back code. You own the platform and its roadmap.
Content updated: March 31, 2026