Building on arXiv:0912.1723 [1], in this paper we investigate the AdS 3 /CFT 2 correspondence using integrability techniques. We present an all-loop Bethe Ansatz (BA) for strings on AdS 3 × S 3 × S 3 × S 1 , with symmetry d(2, 1; α) 2 , valid for all values of α. This construction relies on a novel, α-dependent generalisation of the Zhukovsky map. We investigate the weakly-coupled limit of this BA and of the all-loop BA for strings on AdS 3 × S 3 × T 4 . We construct integrable short-range spin-chains and Hamiltonians that correspond to these weakly-coupled BAs. The spin-chains are alternating and homogenous, respectively. The alternating spinchain can be regarded as giving some of the first hints about the unknown CFT 2 dual to string theory on AdS 3 ×S 3 ×S 3 ×S 1 . We show that, in the α → 1 limit, the integrable structure of the d(2, 1; α) 2 model is non-singular and keeps track of not just massive but also massless modes. This provides a way of incorporating massless modes into the integrability machinery of the AdS 3 /CFT 2 correspondence.