Cashier-BTC

Cashier-BTC is a self-hosted Bitcoin payment gateway, which directly aligns with the 'Payment Processing' and 'Online Payments' features. It provides a REST API for integration, fulfilling 'Developer API Integration' and 'Developer Tools'. The API also includes functionality for 'request_payment' which acts as 'Invoicing' and 'Invoice Creation & Sending'. While it focuses on Bitcoin, the core functionalities of a payment platform are present. The 'in-person-payments' feature is inferred from the general nature of a payment gateway that could be integrated into POS systems, although not explicitly stated for in-person card processing.