The latest generation of DEPFET active pixel sensors produced in MOS technology with two metal and two poly-silicon layers has been designed in different shapes and sizes for a variety of applications in X-ray imaging and particle tracking at ILC and SuperBelle. The DEPFET is a field effect transistor with an additional implant underneath the channel and integrated on a fully depleted substrate. It combines the functions of a detector and the first amplification stage in one single device.This paper describes the application of the DEPFET for vertex detectors at collider experiments. Since the DEPFET has recently become the baseline technology for the upgradation of the SuperBelle Vertex detector, emphasis will be given to the performance of a DEPFET based pixel vertex detector, the radiation hardness and the thinning technology.