Electron polarimetry benefits from the ability to use processes with well-known analyzing powers, hence enabling high precision measurements. Several techniques are employed to measure electron beam polarization, including Mott, Møller, and Compton polarimetry. Each technique has particular advantages and disadvantages, depending on the application. This chapter will focus on the techniques used to measure electron beam polarization, with particular emphasis on the challenges and requirements for achieving high precision. The development of a conceptual design of a Compton polarimeter for the future Electron Ion Collider will also be discussed.