Karny is a free digital credit book designed to help manage your business and credit and debit transactions with your customers and suppliers. The app is 100% free, safe, and secure, allowing you to keep track of all your transactions with a third party and record them securely. You can also remind your clients of their situation by sending them reminders via WhatsApp or SMS to receive payments.

Karny's interface is simple and intuitive, making it easy to use. The app's key features include the ability to create a credit book using your phone number, register clients, record transactions, and track balances in real-time. You can also send reminders via WhatsApp or SMS, and your clients can view their invoices online without having to download the app. Karny is suitable for all types of businesses, small and medium-sized, making sales on credit, providing a free alternative to cash register and Point of Sale (POS) software.