SolAR is an open source framework dedicated to augmented reality (AR). It is promoted by the XR4ALL project and hosted on GITHub. It offers a C++ and C# SDK to easily and quickly develop and use custom computer vision solutions addressing mixed reality applications. It provides developers with a full chain from low-level vision components development to high-level computer vision pipelines and XR service development. Currently focusing on camera pose estimation, it will be soon be extended to support also dense 3D reconstruction and scene understanding. The SolAR framework is open-source and released under Apache license 2.0, and this allows it to be used for research as well as for commercial purposes addressing various domains (smart factory, smart home, real estate, health, etc.). SolAR aims at stimulating the interaction between all XR actors for the benefit of end users.