HERMES is an oncoming constellation of 6 3U CubeSats which will provide an all-sky monitor for gamma-ray bursts and other astrophysical transients. Each Cubesat is equipped with a detector based on GAGG scintillator crystals and Silicon Drift Detectors. This design, also known as "Si-swich", allows to detect photons over a wide energy range spanning 2 keV to 2 MeV. At IAPS, we are working on the assembly and the calibration of the HERMES payloads. To date, 4 out of 6 instruments have been completed. The HERMES satellite constellation will be deployed to near-equatorial orbits during 2024. HERMES is a collaboration that encompasses both domestic and international scientists and institutions. For example, the miniaturized computer which serves the HERMES payload is supplied by the Astronomisches Institut Tuebingen (IAAT).