  The Kerr spacetime is a fundamental solution of general relativity (GR),
describing the gravitational field around a rotating, uncharged black hole
(BH). Kerr spacetime has been crucial in modern astrophysics and it serves as a
foundation for the study of gravitational waves (GWs). Possible deviations in
Kerr geometry may indicate deviations from GR predictions. In this work, we
consider the Johannsen-Psaltis metric, which is a beyond-Kerr metric
characterized by a single free parameter, and then we probe this theory
framework using several GWs observations from the third Gravitational-wave
Transient Catalog (GWTC-3). We find that, for most of the events analyzed,
there are no significant deviations from the null hypothesis, i.e. the Kerr
metric. Our main findings demonstrate alignment and certain enhancements when
compared to previous estimates documented in the literature.
