Ariba - Ariba is a software and information technology services platform providing companies with collaborative business commerce solutions.

FusionInvoice - Self hosted invoicing for freelancers and small businesses

Precoro - Precoro is a robust procure-to-pay system for your business. Automated purchasing, simple sourcing and spend analytics — all in one easy-to-use platform!

Invoice Ninja - Invoice Ninja is a free, open-source solution for invoicing and billing customers.

Procurify - Reinvent the way organizations spend to make the purchasing process more accessible, manageable and convenient.

Bahaquote - Bahaquote offers complete online invoicing and billing software designed to seamlessly integrate with any business.