ERPNext

Full open-source ERP with a first-class CRM, selling and support suite.

ERPNext is a comprehensive open-source ERP built on the Frappe framework in Python with a JavaScript frontend and a MariaDB/PostgreSQL backend. Beyond accounting and inventory it ships a complete CRM module covering leads, opportunities, quotations, sales orders, and a help-desk, all sharing one metadata-driven data model. It is notable for its low-code DocType system, broad business coverage, and large self-hosting community.