Ryu comprises a web server function synonymous with Web Server Gateway Interface (WSGI), which acts as an interface that can be used to introduce newer REST APIs into an application. Some of the northbound APIs are:

• ofctl_rest.py, which presents a set REST API for updating and collecting switch statistics
• rest_conf_switch.py, which is centered around APIs for the switch configuration
• rest_topology.py, centered around the link configuration
• rest.py, which provides a set of REST APIs for network registration and management of the endpoint (primarily MAC address and OpenFlow port number)
• rest_nw_id.py, used to know the specific port which is reserved or used for GRE
• rest_router.py, used for obtaining, modifying, or deleting address data and routing data