chipKit was created in In May 2011 by Microchip Technology and Digilent by the release of two boards, the chipKIT UNO32 and the chipKIT MAX32. The boards used Microchip PIC32 Microcontrollers and brought 32bit performance to a platform compatible with Arduino.
chipKIT boards are designed to be form factor compatible with existing Arduino™ boards and the pin-out has been designed to match the modeled board as closely as possible.
chipKit boards use PIC32 MCUs which are 3.3V devices, not 5V, but with all pins on the chipKIT boards being 5V tolerant.
chipKit uses its own IDE software called MPIDE, but this is a fork from the Arduino IDE software.