  We present the Living Swift-XRT Point Source catalogue (LSXPS) and real-time
transient detector. This system allows us for the first time to carry out
low-latency searches for new transient X-ray events fainter than those
available to the current generation of wide-field imagers, and report their
detection in near real-time. Previously, such events could only be found in
delayed searches, e.g. of archival data; our low-latency analysis now enables
rapid and ongoing follow up of these events, enabling the probing of timescales
previously inaccessible. The LSXPS is, uniquely among X-ray catalogues, updated
in near real-time, making this the first up-to-date record of the point sources
detected by a sensitive X-ray telescope: the Swift-X-ray Telescope (XRT). The
associated upper limit calculator likewise makes use of all available data
allowing contemporary upper limits to be rapidly produced on-demand. These
facilities, which enable the low-latency transient system are also fully
available to the community, providing a powerful resource for time-domain and
multi-messenger astrophysics.
