RAN slicing is one of the key enabler to enable virtualization of a BS and its delivery as a service with dierent levels of network isolation and sharing so as to accommodate the needs of mobile network operators and verticals. In this demonstration, we show a prototype of a RAN slicing runtime system to enable exible slice customization on the top of a disaggregated RAN infrastructure  with dierent levels of isolation and sharing in terms of resources and network functions, while retaining the quality of service (QoS) for dierent slice instances. Furthermore, a novel plug & play network application chaining framework empowered by a network software development kit (SDK) is demonstrated to show how the multi-service programmability on per-slice basis can be achieved. Our demonstration is based on the OpenAirInterface , Mosaic-5G FlexRAN  and LL-MEC  platforms. Finally, we highlight how the the proposed approach can be extended to an end-to-end network slicing scenario.