Dolibarr is an open source PHP backend management system and ERP. It has a unique object-oriented programming model where objects like products and orders inherit from a common object. Modules in Dolibarr have context available for the user, configuration, and languages. Key constructs for developing modules include the module descriptor configuration file, directory tree structure, admin management parameters, constants, rights/permissions, menu and tab systems, views, substitution variables, and SQL models. Best practices for module development include sanitizing menu IDs to prevent XSRF attacks, keeping modules simple, consulting documentation, reviewing example modules, properly attributing licensing, and developing honorably without plagiarism.