X-ray based structural biology has advanced the understanding of biological macromolecules, such as proteins and nucleic acids, by providing atomic level detail. Biological macromolecules, however, are not static and have intricate interactions with many binding partners, including ions, small molecules, and other macromolecules. Recent advances in X-ray sources, with the development of X-ray Free Electron Lasers and fourth-generation synchrotrons, have contributed to the exciting development of time-resolved techniques that allow for structural dynamics to be directly measured. In particular, microfluidic mixers are extremely versatile and well posed to rapidly combine multiple species for reaction initiation. The freshly mixed sample can then be directly delivered, at pre-set time delays, to the X-ray beam to probe its structure as the reaction progresses. Here, I present several successful applications of time-resolved X-ray experiments with diverse biological samples, various structural biology techniques, multiple X-ray sources, and different types of microfluidic mixers. These developments expand the types of time-resolved experiments that can be performed, and overcome previous limitations related to X-ray source type and the size of the species that can be mixed.