Testing the Standard Model with rare decays at the LHCb

The study of rare decays of B, D and K mesons (as well as $\tau$ leptons) can provide either very stringent tests for the Standard Model or excellent opportunities to search for hints of new physics beyond the SM. A review of the recent results of studies of such rare decays from analysis of $pp$ collision data recorded at the LHCb experiment at CERN, is presented. All decays channels studied so far are in agreement with SM predictions.