I will review how integrability can be used to understand the spectral problem (including massless modes) of Type IIB string theory on AdS3 x S3 x T4 with R-R flux. I will then show how integrability emerges in the dual CFT2. This provides arguably the first non-BPS test of the planar AdS3/CFT2 correspondence in the literature and gives strong evidence in identifying particular points in the moduli space of the dual theories.