Proprietary software is rarely web-based. Usually, it requires setting up a local server (or multiple servers) at the enterprise automated. This way all the information (as well as the license keys) is stored in a local network. On the contrary, open source ERP software is usually web-based. It is developed on stacks that often include Java, Ruby or PHP along with MySQL or PostgreSQL. 

It is worth mentioning that project owners often mention ERP when they need only one type of management (one key feature) to be developed. When they say "ERP", they mean automation of any kind, like just inventory management or HR management. A work scope tied up with such projects makes them very suitable for custom development from the ground up. 

Key features 

• Inventory management 

• Human resources 

• Order processing 

• Project management 

• Manufacturing 

• Financial accounting 

• Billing and payment 

• Customer relationship management