UNSIO is an API that performs input/output operations in a generic way and supports different kinds of nbody files format such as NEMO, Gadget binaries 1 and 2, Gadget hdf5, Ramses. It allows users to write only one analysis program that works on all known files format supported by UNSIO. It also comes with an integrated sqlite3 database to retrieve data automatically among terabytes of hard disks.