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

VOGSY - Professional service automation tool built on Google G Suite

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

Office Timesheets - Professional Services Automation

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

Timewatch - Timewatch offers time tracking, expense management, resource scheduling and professional services automation solutions.