In this paper we describe the design and implementation of feqb, a tool that synthesizes sound equality tests for inductive data types in the dependent type theory of the Coq system. Our procedure scales to large inductive data types, as in hundreds of constructors, since the terms and proofs it synthesizes are linear in the size of the inductive type. Moreover it supports some forms of dependently typed arguments and sigma types pairing data with proofs of decidable properties. Finally feqb handles deeply nested containers without requiring any human intervention.