Argotec HACK OBC offers unprecedent flexibility thanks to its design developed from scratch to be modular and easily reconfigurable. Different standard modules, based on both state-of-the-art SoCs and FPGAs, can be assembled without the need of external harness to face a wide variety of applications, from spacecraft management to hardware acceleration. The design leverages a mix of rad-hard, defense-grade and automotive components carefully selected to enable the execution of demanding edge-computing tasks while ensuring a reliability level significantly higher than standard CubeSat avionics. Each HACK module is designed to be powered by a single +5V DC rail and has standardized thermal and mechanical interfaces, allowing the installation both as single unit or as part of a complex OBC subsystem. The standard configuration, which includes one Core Board and one aXelerator Module, has a volume of about 0.5U and offers unmatched performance and interfaces.