We present a coherent X-ray scattering technique that allows in situ measurements of electrode surface dynamics. This technique can measure the transient dynamics of phase relaxation from one phase to another upon changing electrochemical conditions or temperature. It can also measure the dynamics of microstates even if the electrode is apparently static in macroscopic states. We will discuss the underlying physics of the X-ray speckle correlation spectroscopy and present our recent study of Au (1 0 0) surface in vacuum, water, and electrolytes. (C) 2012 Elsevier Ltd. All rights reserved.