Systems Integration & Test Engineers focus on assembling system components and validating that integrated systems function correctly as a whole. Their responsibilities include integration planning, interface testing, system-level test execution, fault isolation, and performance validation. They work closely with design, verification, and operations teams to identify integration issues and ensure readiness for deployment. These engineers use test environments, simulation tools, and automated testing frameworks across hardware and software systems. They operate in aerospace, transportation, defense, industrial automation, and complex digital platforms. Globally, demand remains strong as increasingly integrated systems require rigorous end-to-end testing to ensure reliability and operational success.