The document discusses how Internet of Things (IoT) uses an edge layer to connect smart devices to servers due to the large number and varying quality of connections from devices. It describes how MuleSoft provides a reference architecture covering the client, edge, and server layers for IoT applications. MuleSoft fits into IoT by enabling its engine to be embedded in devices, ensuring data integrity and orchestration between sensors and backend systems by acting as an intermediary that connects devices using various protocols.