Juniper Extension Toolkit (JET), an evolution of the Junos SDK, provides a modern, programmatic interface for developers of third-party applications on Junos devices. It focuses on providing a standards-based interface to the Juniper Networks Junos operating system (Junos OS) and Junos OS Evolved for customizing management and control plane functionality. JET also includes a toolchain along with libraries and other tools to enable developers to write on-device JET applications.