Deltacloud API is a cloud-agnostic provisioning and management API that allows users to manage resources like virtual machines, storage, and images across different cloud infrastructures through a single REST-based interface. It aims to avoid vendor lock-in by providing an abstraction layer that can integrate with APIs from multiple public and private cloud providers. The Deltacloud API supports common operations like launching, managing, and terminating virtual machine instances as well as extended resources like storage volumes and load balancers. It uses a RESTful design to provide a language-agnostic interface and has client libraries available in several programming languages.