Frappe is an open-source web application framework designed for building custom applications quickly and efficiently. It provides a robust set of tools and features, including a user-friendly interface, a powerful database, and built-in support for REST APIs. Developers can create applications tailored to specific business needs without starting from scratch. The framework is particularly known for its integration with ERPNext, a popular enterprise resource planning software. This allows users to manage various business processes seamlessly, such as accounting, inventory, and customer relationship management, all within a single platform.