In the IT project, the traditional testing method is creating test scenarios/cases according to the business flow, manually defining, and testing whether the output value is correct for each input value. Besides, massive test data is also required to perform the test accurately. So far, the traditional IT project has opened the system after manual iterating scenarios/cases tests that are empirically considered sufficient. However, due to time and resources limitation, this method cannot consider all possible cases in the real world. Thus, we cannot test all scenarios and eliminate all potential defects through this traditional testing method. As a result, unexpected errors or exceptional situations often occur even after the system goes live, which can lead to severe failure. This paper demonstrates a real transaction-based automatic testing solution called ‘PerfecTwin’ with real-world examples. PerfecTwin highlights to overcome the limitation of the traditional manual test by automatically verifying the TO-BE system with the AS-IS system’s actual transaction, which can allow eliminating all the defects before the system goes live.