Application service provider featuring application programming interface (API) software in the fields of integrated direct health care administration, patient care, and healthcare management for patient invoicing and billing, for payment tracking, management, and discounting, for appointment calendaring and scheduling, health plan membership enrollment, patient communications, managing appointment and payment reminders, appointment and payment tracking, recording and managing patient medical history, accounting, reporting financial and payment transactions, employee payroll management, patient insurance eligibility management, inventory management, creating and managing patient profiles, and automated workflow in the nature of automated patient communications and billing management