Simple Invoices is an open source billing application. Simple Invoices was initially released in 2007. Simple Invoices is a billing (aka invoicing) application that focuses on simplicity while still providing advanced features.

Why should I use Simple Invoices?

• Absolutely free, no monthly subscription
• Browser based application you can use from anywhere
• It's open source, developed by the community and it's yours
• Easily track your finances, send invoices as PDF's and hundreds of other great features