Opentaps is a web based ERP

Enterprise resource planning

Enterprise resource planning systems integrate internal and external management information across an entire organization, embracing finance/accounting, manufacturing, sales and service, customer relationship management, etc. ERP systems automate this activity with an integrated software application...

 and CRM

Customer relationship management

Customer relationship management is a widely implemented strategy for managing a company’s interactions with customers, clients and sales prospects. It involves using technology to organize, automate, and synchronize business processes—principally sales activities, but also those for marketing,...

 for small to medium sized businesses based on Apache Open for Business

Apache OFBiz

Apache Open For Business is an open source enterprise resource planning system. It provides a suite of enterprise applications that integrate and automate many of the business processes of an enterprise....

. Its functions include eCommerce, Point-of-Sales, inventory, warehouse, order, customer management and general ledger. It also offers built-in business intelligence tools and mobility integration, including with Microsoft Outlook, Google Calendar, and mobile phones.
Opentaps has a web based UI (user interface).