The Single Particles, Clusters, and Biomolecules & Serial Femtosecond Crystallography (SPB/SFX) instrument of the European XFEL is primarily concerned with three-dimensional diffractive imaging, and three-dimensional structure determination, of micrometre-scale and smaller objects, at atomic or near-atomic resolution.

A particular emphasis is placed on biological objects—including crystals of macromolecules and macromolecular complexes as well as viruses, organelles, and cells—though the instrument will also be capable of investigating non-biological samples using similar techniques. Furthermore, the SPB/SFX instrument aims to study structural dynamics in these biological systems on the millisecond to femtosecond timescale.

The SPB/SFX instrument consists of two experiment endstations (upstream and downstream), based on the combined contributions of European XFEL and the Serial Femtosecond Crystallography (SFX) user consortium.