DPsim is a solver library for dynamic power system simulation. It supports the electromagnetic transient (EMT), quasi-static and dynamic phasor (DP) domain for simulation. A powerflow solver is included for standalone usage or to initialize dynamic simulations. It provides a Python module which can be embedded in any Python 3 application / scripts. The simulation core is implemented in highly-efficient C++ code. It supports real-time execution with time-steps down to 50 uS. It can load models in the IEC61970 Common Information Model (CIM) / Common Grid Model Exchange Standard (CGMES) XML format. It can be interfaced to a variety of protocols and interfaces via VILLASnode. https://github.com/sogno-platform/dpsim