InvoiceNinja

Invoice Ninja is the #1 open-source platform to create and email invoices, track payments and expenses, and time billable tasks and projects for clients.

Features:

• Invoices & Auto-Billing
• Online Payments
• Quotations & Proposals
• Streamline Workflows
• Time-Track Work
• Expenses & Reporting

Invoice Ninja is 100% open source, and supported by a growing community of developers around the world.