A common software for future colliders: The Key4hep turnkey software stack

Software tools are foundational for the development of future collider experiments. Detector optimization and physics performance studies crucially depend on the availability of performant and reliable software libraries for Monte Carlo generation, detector simulation, reconstruction, and analysis. The Key4hep project aims at providing infrastructure, interfaces, and a common stack of easy-to-use software tools for future, or even present, High Energy Physics projects. Key4hep is to a large extent based on software tools that are already very actively used in the community - like ROOT, Geant4 and DD4hep - or those that are currently under active development like EDM4hep or ACTS. The Key4hep project is supported by, among others, the HEP Software Foundation, CERN, DESY, IHEP and the AIDAinnova project and has active developers from all large future collider projects: CEPC, CLIC, FCC, and ILC. In this talk we present an overview of the Key4hep project and describe the adaptation processes of the different future experiments, thereby showing that Key4hep is a viable long term solution as baseline software for high energy experiments that will facilitate the scientific exchange and make similar studies easier and more efficient.