Shift-left testing is an approach that integrates testing earlier in the software development lifecycle, aiming to identify and fix defects at the earliest stages to save time and resources. This method encourages collaboration among developers, QA, and operations teams, fostering a more streamlined and efficient process. In practice, shift-left testing often involves techniques such as unit testing, behavior-driven development (BDD), and test-driven development (TDD), which allow developers to anticipate potential issues early on. It also emphasizes the importance of involving testers from the beginning, utilizing automation, and ensuring comprehensive test coverage. In the context of microservices, this approach enables individual components to be tested independently before integration, ensuring functionality and reducing the risk of defects. The strategy also includes security testing to detect vulnerabilities early, ultimately leading to improved software quality, reduced development costs, and enhanced collaboration within teams. As organizations seek efficiency in development, shift-left testing has become increasingly popular for its ability to enhance software quality and reduce time-to-market.