Gauge invariance and non-Gaussianity in Inflation

We clarify the role of gauge invariance for the computation of quantum non-Gaussian correlators in inflation. A gauge invariant generating functional for n-point functions is given and the special status of the spatially flat gauge is pointed out. We also comment on the relation between gauge transformations, field redefinitions, the choice of $t=\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{s}\mathrm{t}$ hypersurfaces and the use of boundary terms in computations of non-Gaussianity.