The ESCAPE Open-source Scientific Software and Service Repository (OSSR) is an open-access repository to share scientific software and services to the science community and enable open science. It will house astro-particle-physics-related scientific software and services for data processing and analysis, as well as test data sets, documentation, tutorials, presentations and training activities. It will enable a true multi-messengerdata-driven cooperative approach based on the FAIR principles, guaranteeing an open innovation environment for science interoperability and software re-usage.