Abstract: A component die validation built-in self-test (VBIST) engine is presented. In an aspect, a component die includes component circuitry for performing a component function, interface circuitry for communicating with another die, and a VBIST circuit. The VBIST circuit includes a traffic generator that generates test data streams, a tracker that receives and validates test data streams, and a configurable switching matrix for coupling the traffic generator to at least one of the component circuitry, the interface circuitry, or the tracker, and for coupling at least one of the component circuitry, the interface circuitry, or the traffic generator to the tracker. The VBIST circuit can send traffic to and from the component circuitry directly, or indirectly via the interface circuitry in loopback mode, and can be used for memory initialization and test.