Mule is an integration platform that allows systems, services, APIs and devices to connect through a single runtime engine. It handles message routing, data mapping, orchestration, reliability, security and scalability between integrated nodes. Mule can connect other systems and applications, managing communication and allowing monitoring of the application ecosystem. It offers features like deploying on-premises or cloud applications, using connectors for SaaS integration, building and exposing APIs, consuming APIs, creating web services, interfaces for mobile apps, integrating B2B solutions, moving apps to cloud, and connecting e-commerce activities.