Dolibarr

An ERP and CRM suite aimed at small and mid-sized businesses, Dolibarr covers customers, suppliers, products, stock, invoicing, accounting, and basic project tracking in one PHP application. Modules can be enabled as needed, several companies can be handled from the same install, and documents such as quotes, orders, and invoices are generated from shared data.

Small teams use it to replace a stack of separate tools for sales, purchasing, and bookkeeping.

Installing it on your own server keeps commercial and financial records inside your network, avoids recurring per-user subscriptions, and lets you manage database and file backups.