This deep dive explores the concept of headless commerce and introduces vendor, an open-source, enterprise-ready framework designed for complex B2B sales and multi-vendor marketplaces. Unlike traditional all-in-one platforms, headless commerce decouples the front-end (customer interface) from the back-end (commerce logic) using APIs, offering greater flexibility. Vendor, built with TypeScript and Node.js, provides a robust commerce framework and a customizable admin dashboard. Its key advantage lies in its extensible plug-in architecture, allowing businesses to tailor the platform to unique needs, such as intricate B2B pricing, multi-step approval chains, marketplace management, and custom D2C experiences. The platform emphasizes developer experience with tools like GraphQL for efficient data fetching and a CLI for automation. Vendor offers full ownership and control, with a GPL v3 license for the core and optional commercial licenses for enterprise support. The project boasts a healthy ecosystem with significant GitHub stars, forks, and a large contributor base, alongside an active developer community. Ultimately, vendor represents a shift towards flexible, developer-centric solutions for businesses whose models outgrow standardized platforms, potentially becoming the new default in e-commerce.