Develop, maintain, and optimize scalable automation frameworks using technologies such as Selenium, Java, TestNG, Cucumber, REST Assured (or equivalent API automation frameworks), and to support cross-browser, cross-device, parallel, and environment-agnostic test execution. Design, develop, execute, and maintain manual and automated test cases, test scripts, and test suites for web, and web service/API applications based on business requirements, user stories, acceptance criteria, and technical specifications.