The FHI-aims software package is an all-electron, full-potential electronic structure code utilizing numeric atom-centered basis functions for its electronic structure calculations. The localized basis set enables the accurate treatment of all electrons on the same footing in periodic and non-periodic systems without relying on the approximation for the core states, such as pseudopotentials. Importantly, the basis sets enable high numerical accuracy on par with the best available all-electron reference methods while remaining scalable to system sizes up to several thousands of atoms. In order to achieve this for bulk solids, surfaces or other low-dimensional systems and molecules, the choice of basis functions is crucial. The workload of the simulations is efficiently distributable for parallel computing using the MPI communication protocol. The code is routinely used on platforms ranging from laptops to distributed-parallel supercomputers with ten thousand CPUs, and the scalability of the code has been tested up to 100,000's of CPUs.