Pydelay - a python tool for solving delay differential equations. pydelay is a program which translates a system of delay differential equations (DDEs) into simulation C-code and compiles and runs the code (using scipy weave). This way it is easy to quickly implement a system of DDEs but you still have the speed of C. The Homepage can be found here: It is largely inspired by PyDSTool. The algorithm used is based on the Bogacki-Shampine method [1] which is also implemented in Matlab’s dde23 [2]. We also want to mention PyDDE – a different python program for solving DDEs.