Konik provides an easy way to create, read, and validate ZUGFeRD invoices. It features an easy and understandable API, extensive documentation with examples, logical invoice validation with JSR303, validation of invoices against ZUGFeRD profiles, validation of invoices against specific country invoice regulations, easy invoice appending or extracting in and from PDFs, and multiple PDF Carriages from different vendors.
MacFreelance is an application for invoicing, billing and managing clients. It generates professional invoices, monitors time spent on projects, tracks mileage and payments, performs tax calculations, and generate detailed reports. It supports multiple companies to bill from, fixed or timed charges and billing in hours, minutes, days, weeks, or months, project quotes, global currency support and tax calculations, and integration with Address Book, iCal, and Spotlight.