Flow-based programming is a paradigm that defines applications as networks of black box processes that exchange data via message passing through predefined connections. Processes have ports for communication and are connected externally without awareness of each other. This approach improves workflow visualization and allows processes to be reused. GoFlow is a Golang library that implements this model by defining components as processes with input/output ports and connecting them to build an application graph. It supports various concurrency models and locking for state management.