As the 5G standards mature and awareness of the capabilities of the technology increases, industry verticals are becoming more eager to test new services and develop them to the level of maturity required for market adoption. Network slicing, i.e. multiple virtual networks running on a common infrastructure, is considered a key mechanism to serve the multitude of tenants (e.g. vertical industries) targeted by forthcoming fifth generation (5G) systems, in a flexible and cost-efficient manner. It is predicted that one of the most popular models for customers will be the Network Slice as a Service (NSaaS) model. This model allows a Network Service Customer to order and configure a Network Slice and offered it as a service. This work presents Openlice a Service based, opens-ource OSS for delivering NSaaS following emerging standards from SDOs. We strongly believe that such open source solutions make it easier for organizations to enable complex scenarios especially in the are of Non-Public Networks.