We will perform a new laboratory-based search of hypothetical axions and axion-like particles in the sub-keV mass range. The axion is a particle originally hypothesised to solve the charge-parity (CP) problem of quantum chromodynamic, but variants, called axion-like particles (ALPs), also arise abundantly in string theory. While lighter axions may constitute the dark matter, it has been suggested that ALPs of ~keV mass could also be related to anomalous phenomena such as solar coronal heating and x-rays from the dark side of the moon, so they are well motivated and of interest from many perspectives. Laboratory-based searches of keV mass ALPs have so far only been performed at 3rd generation synchrotron facilities; however, with the advent of XFELs, much brighter photon pulses are becoming available together with noise-free photon-counting detectors, allowing for the proposed experiments to surpass the previous detection sensitivity by several orders of magnitude.