JEM-X: three years in space

We report on the technical and scientific performance of JEM-X, the X-ray monitor on ESA's INTEGRAL mission. INTEGRAL has now been in orbit for more than three years, and the mission is foreseen to be extended until the end of 2010. Overall, JEM-X performs very well, and can be expected to continue to do so for the duration of the mission. We discuss in some detail the operational experiences and the problems encountered with the microstrip detectors caused by the space environment and give one example of the interesting scientific results obtained. The analysis software is still being improved on, and we discuss briefly the significance of these improvements.