ddfermi -- a drift-diffusion simulation tool. ddfermi is an open-source software prototype which simulates drift diffusion processes in classical and organic semiconductors. Key features: finite volume discretization of the semiconductor equations (van Roosbroeck system); thermodynamically consistent Scharfetter-Gummel flux discretizations; general statistics: Fermi-Dirac, Gauss-Fermi, Blakemore and Boltzmann; multidimensional devices; based on pdelib and interfaced via Python or Lua.