The GROMACS project started in 1995 as one of the first-ever parallel simulation codes, the international development team is lead by the KTH partner, and the project is strongly focused on simulation efficiency and generality. It is the only package to support all common force fields and it has a very wide range of simulation algorithms. This combined with the very liberal (and business-friendly) licensing is likely a major factor why it is used as a simulation, minimization and energy evaluation library by several other applications e.g. in bioinformatics or distributed computing projects such as Folding@Home. The code is portable to a very wide range of platforms (including embedded ones), it includes manually tuned assembly kernels for a dozen different architecture instruction sets and accelerator support both for CUDA GPUs and Xeon Phi processors. The package uses state-of-the-art neutral territory domain decomposition and multi-level parallelization to enable scaling both to tens of thousands of nodes on supercomputers and efficient high-throughput computing with accelerators (Pall et al. 2014).