Invoice Ninja

Invoice Ninja is an invoicing and billing application designed for freelancers and businesses running on Linux environments. The software provides tools to generate professional invoices, send them directly to clients, and process online payments through various payment gateways. Users can track project expenses, monitor billable hours using a built-in timer, and convert task lists into formal invoices. The platform includes client management features to store contact information and payment histories, alongside reporting dashboards to review financial metrics and outstanding balances.