With over 35,000 GitHub stars and 460 contributors, Medusa is the headless commerce framework that gives development teams full ownership of their e-commerce backend without license fees, per-transaction charges, or revenue sharing. The modular architecture ships over 18 domain modules covering products, collections, categories, inventory, pricing, carts, orders, payments, fulfillment, promotions, customers, users, API keys, and stock locations, each independently usable and replaceable. REST and GraphQL APIs expose every commerce operation to any frontend framework — official starters exist for Next.js with community options for Nuxt, Remix, and Gatsby. The React-based admin dashboard provides out-of-the-box order management, product maintenance, promotions configuration, B2B accounts, and multi-warehouse inventory, extensible via the Admin SDK for custom views and workflows. The workflow engine orchestrates long-running commerce processes like checkout, fulfillment, and returns with compensating transactions for reliability. Over 200 official and community plugins integrate Stripe, PayPal, Klarna, Algolia, Meilisearch, SendGrid, Mailchimp, Contentful, Sanity, and Klaviyo. Native multi-region and multi-currency support handles tax-inclusive pricing, region-specific payment and fulfillment providers, and localized storefronts from a single backend. Enterprises including Viessmann, Makro PRO, and INSPIRED Pet Nutrition run Medusa in production. Self-hosting deploys via Docker or directly on Node.js with PostgreSQL and Redis. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.

Magento's extensibility without PHP, Shopify's polish without the platform tax: EverShop is the TypeScript-first e-commerce platform built on that promise. Architected as a modular monolith on Node.js, it organizes every piece of business logic - catalog, checkout, customers, your custom extensions - into modules that plug in without touching core code, extended through a disciplined set of mechanisms: registry processors for transforming data across modules, hooks that wrap function calls, async event subscribers (product created, order placed), and route middleware. The storefront and the fully-featured admin panel are both React with server-side rendering and hydration, giving fast first paint and SEO-friendly pages, while a typed GraphQL API (plus REST endpoints) serves exactly the data each view needs - the same API that powers headless and PWA builds. Standard commerce is covered: product management with variants and attributes, category navigation, cart and checkout, order and customer management, coupons, and a theme system built on React components and Tailwind for deep storefront customization. PostgreSQL is the default database, deployment is Docker-friendly with near-zero configuration, and the GPL-3.0 license means the entire stack - types, resolvers, and checkout flow included - is yours to read and modify.

Backed by 23,000+ GitHub stars and trusted by global brands processing millions of orders, Saleor delivers the open-source headless commerce API that replaces monolithic ecommerce platforms with a composable, GraphQL-native architecture where APIs are the only way to interact with the system. The core engine built on Python and Django handles catalog management, order processing, payment orchestration, inventory tracking, and fulfillment workflows while remaining completely decoupled from any frontend technology. Native multichannel support enables per-channel control of pricing, currencies, warehouses, product availability, and payment methods, managing Instagram, Amazon, regional websites, and retail POS from a single backend. The extensibility layer provides 160+ webhooks spanning synchronous payment callbacks, asynchronous event notifications via Google Cloud Pub/Sub and AWS SQS, and subscription queries that shape webhook payloads to deliver only the data your services need. Dashboard UI Extensions offer 45+ mount points for embedding custom interfaces via iframes without forking, while the Apps system allows building payment gateways, PIM integrations, loyalty programs, and discount logic in any language. The React-based administration dashboard provides product management, order processing, customer segmentation, and analytics with multi-language and multi-currency support. OIDC integration connects existing identity providers for single sign-on across the merchant organization. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. BSD 3-Clause licensed.