Flavour-Changing Neutral-Current (FCNC) processes are exceptionally sensitive to New Physics (NP) effects and in particular to particles that could exist beyond the Standard Model (SM) but are too massive to be directly produced at present colliders. These particles can appear as virtual contributions that may induce significant effects on branching fractions and angular observables. A review of the present flavour anomalies observed by the LHCb experiment in the context of FCNC processes proceeding through $b\rightarrow s \ell^{+} \ell^{-}$ transitions is given. The results discussed are obtained from data collected at $\sqrt{s}=7$ and $8$ $\mathrm{TeV}$ during Run 1, corresponding to 3 $\mathrm{fb^{-1}}$ of integrated luminosity. Results exploiting the data from Run 2 collected at $\sqrt{s}=13$ $\mathrm{TeV}$ and corresponding to 2$ \ \mathrm{fb^{-1}}$ of integrated luminosity, are also included.