Medusa

Medusa is an open-source commerce platform for building custom digital commerce applications in Node.js and TypeScript. The @medusajs/medusa package is the core of the framework, wiring together dozens of first-party modules (cart, order, payment, pricing, inventory, fulfillment, tax, customer, and more) into a coherent commerce backend with a REST API and an admin dashboard.

Rather than a rigid, monolithic storefront, Medusa is built as a modular framework: each commerce domain is an independent module, orchestrated through workflows and linked via its module system, so teams can extend, replace, or add capabilities without forking the core. This makes it a foundation for bespoke e-commerce, marketplaces, B2B, and other commerce experiences.

What You Get

• A complete commerce backend with cart, order, payment, pricing, inventory, and fulfillment modules
• A built-in admin dashboard and REST API for managing commerce data
• A module system for adding, replacing, or extending commerce domains
• Workflow orchestration for composing multi-step commerce operations
• First-party integrations for auth, notifications, file storage, caching, and locking

Common Use Cases

• Building a custom online store or headless storefront backend
• Creating a marketplace or B2B commerce application with bespoke logic
• Extending a commerce backend with custom modules and workflows

Under The Hood

Architecture - The @medusajs/medusa package is the composition root of a large monorepo: it depends on the @medusajs/framework runtime plus dozens of domain modules (@medusajs/cart, order, payment, pricing, inventory, fulfillment, tax, customer, etc.) and @medusajs/core-flows, wiring them through the module system and orchestration engine into an application with a REST API and the @medusajs/dashboard admin UI. Tech Stack - TypeScript across the board, organized with Turborepo and Yarn workspaces; modules use a consistent data/service layer, with Redis and Postgres options for caching, locking, event bus, and workflow engines provided as swappable packages. Code Quality - The repo is heavily tested with Jest, includes integration-tests/ and per-package suites, CODEOWNERS, contribution and security policies, and a rigorous release/changelog process, reflecting mature engineering practices. API Design - Medusa exposes ergonomic building blocks: modules with typed service interfaces, a workflow SDK for composing operations, and a link module for cross-module relations, letting developers extend commerce behavior without patching the core.