Bill.com - Bill.com provides ACH payments processing, automates your accounts payable and accounts receivable processes.

BillGrid.com - BillGrid is an easy to use online invoicing, billing and expense management system that will save you time with tracking clients projects, expenses, invoices and payments.

Sage Intacct - Intacct is a cloud-based accounting and financial management system that is designed for the businesses of all levels.

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

Tipalti - Tipalti is a supplier payments automation solution to streamline all phases of the AP and payment management workflow.

Elorus - A super-easy online invoicing & time tracking software