Prometeo is a multi-particle code developed at ENEA within the framework of scientific programs aimed at studying and developing Free Electron Laser (FEL) sources. The code has been used either as a research tool to understand the dynamics of FELs operating in different configurations and as a practical tool to design FEL devices. In this paper we describe the structure of the code and its capability in describing either Oscillator and Single pass configuration. We compare Prometeo performances with those of other existing codes and finally comment on its role in designing high-gain devices as the SPARC source
