Kind 2 is an open-source, multi-engine, SMT-based automatic model checker for safety properties of finite-state or infinite-state synchronous reactive systems expressed as in an extension of the Lustre language. In its basic configuration it takes as input a Lustre file annotated with properties to be proven invariant, and outputs for each property either a confirmation or a counterexample, i.e., a sequence inputs that falsifies the property. More advanced features include contract-based compositional verification, proof generation for proven properties, and contract-based test generation.