Composable commerce and OMS in 2026. How to automate logistics and fulfilment?
TL;DR - Quick summary
- Margin protection: A dedicated OMS in composable stacks optimizes carrier spend by routing each line from the cheapest eligible warehouse or store.
- Beyond SaaS limits: Subscription platforms like Shopify Plus hard-code fulfilment rules. GMI Software implements OMS on open MedusaJS v2 so you can own split-shipment logic.
- Resilient architecture: NestJS microservices talk asynchronously (event-driven), so Black Friday spikes do not lock your WMS.
- Proof at scale: Our commerce work scales in production. The SFD app we built exceeds 100,000 downloads with a 4.9★ App Store rating while handling complex purchase paths.
The problem: one order spanning three warehouses paralyses ops
You run a central DC, a 3PL partner and 10 stores. A shopper buys three SKUs. Legacy monoliths (Magento, PrestaShop) treat that as a single inseparable order.
SKU A ships from the hub, B from the 3PL and C only exists in Kraków. Legacy tooling forces support to cancel, split manually and rebook three parcels-time lost, angry buyers and triple carrier fees that erase margin.
Hiring more logisticians is not the fix. GMI Software in Gdansk (16+ years) ships composable commerce with a dedicated OMS that decides fulfilment in roughly 0.1s without human triage.
Monolithic OMS vs composable commerce
Why enterprises leave all-in-one suites for modular composable stacks:
- Monolithic commerce (classic Magento): Cart, payments, OMS and shipping share one deployable. Impact: A rule like “ship from the Gdansk store, skip the hub” touches core checkout and risks breaking payments.
- Composable commerce (MACH): Next.js storefront, Stripe payments and fulfilment services are independent. Impact: OMS acts as an intelligent router, reads ERP stock and fans work out to warehouses without rewiring the entire storefront.
How we engineer a distributed OMS (GMI stack)
Logistics punishes sloppy code. We keep OMS off the critical path with a proven stack:
- Transactional core (MedusaJS v2): MedusaJS is built for composable patterns on Node.js, giving full control over order lifecycle without per-order SaaS take rates and with 100% code ownership.
- Order routing microservices (NestJS): Complex rules live in dedicated NestJS services that query inventory in milliseconds and command WMS systems.
- Async plumbing (Redis / AWS SQS): Checkout publishes to SQS instead of waiting on carriers. Integrations finish in the background.
- Mobile extensions (React Native): Pickers and drivers get React Native (Expo) apps on the same APIs, typically 30-40% cheaper than dual native builds-similar to logistics rollouts such as EMKA Mobile.
Composable OMS pricing and how we guarantee cost
Headless commerce plus custom OMS is foundation spend, not a skin-deep redesign.
- Composable budget: A greenfield Next.js + MedusaJS platform with advanced multi-warehouse OMS usually lands PLN 200,000-350,000, depending on ERP/WMS integrations.
- MVP timeline: Logistics rewrites and production go-lives average four to eight months.
ERP surprises are why commerce-logistics programs overrun budgets. GMI Software is the only Polish software house pairing MedusaJS composable programs with a fixed-price guarantee after DDT (Discovery, Design & Technology). We map every shipping scenario with your ops team before coding and absorb delivery risk inside the agreed scope.
Frequently asked questions
- What is composable commerce in e-commerce?
- It is a MACH-aligned pattern: compose best-of-breed services-search, payments, OMS-linked via APIs instead of one monolithic suite.
- What does an order management system (OMS) do?
- The OMS ingests paid carts, locates inventory across DCs, 3PL or stores, optimizes parcel economics and sends instructions to WMS and carriers.
- Why do SaaS platforms like Shopify struggle with complex fulfilment?
- Closed SaaS stacks optimize for one-store, one-warehouse flows. Forcing multi-carrier splits by cube weight usually means expensive apps, slower storefronts and extra take-rate fees per order.
- How does MedusaJS v2 help with order management?
- MedusaJS v2 is headless-first with deep order lifecycle hooks. Because it is open Node.js, GMI engineers can extend the core with bespoke B2B rules and warehouse allocation algorithms.
- How should we prepare for a composable OMS rollout with GMI Software?
- We start with DDT workshops. For three to five weeks GMI analysts and architects work with your logistics team to diagram every shipping edge case, then issue a fixed-price quote.
Content updated: March 31, 2026