Strongly coupled quantum field theories (QFTs) are notoriously hard to study. Supersymmetry (S), if present, provides powerful tools to access non-perturbative physics exactly. Stringy constructions of SQFTs - such as Hanany-Witten style brane systems - help us uncover their physics even in regimes completely inaccessible via current field theory methods. After some introduction I will focus on 5d N=1 theories realised on fivebrane webs ending on sevenbranes in the presence of an O7+ orientifold plane in Type IIB String Theory. In particular SO(K) theories with matter in the vector representation and SU(K) theories with matter in the fundamental and second rank symmetric representation, and their infinite coupling UV completions. We will see how to use so called magnetic quivers to study the moduli spaces and partial Higgsings of these theories.