I will review the localisation of 2d N = (2, 2) supersymmetric gauge theories with a vector U(1) R-symmetry on the round 2-sphere, leading to a matrix integral expression for the partition function, in the so called "Coulomb branch" representation. For gauge theories which are completely Higgsed in the presence of a Fayet-Iliopoulos term, an alternative localization scheme yields the "Higgs branch" representation of the same partition function as the product of vortex times antivortex partition functions, weighted by semiclassical factors and summed over isolated vacua on the Higgs branch. Finally, I will briefly overview the potential of these exact results for the study of type II string compactifications and supersymmetric gauge theories in various dimensions. Based on arXiv:1206.2356 with F. Benini.