ChargeOver - ChargeOver automates recurring billing, subscription billing, & payment acceptance. A SaaS that integrates with Xero, Quickbooks, & has an API. Free trial.

Odoo - An all-integrated business app suite to unleash your growth potential.

fusebill - Fusebill is the leading recurring billing and subscription management software for businesses. Try Fusebill for subscription billing made easy!

Epicor Kinetic - Epicor ERP is a global enterprise resource planning solution.

MinuteDock - Web-based time tracking software designed to integrate with the Xero accounting package.

Adempiere - ADempiere is a commons-based peer-production of Open Source ERP Applications.