Automation is a novel approach that can enhance production capacity, work quality, and working environment, while minimizing labor disputes by automating all handling parameters. Formal methods are scientific techniques used to design complex mathematical systems. They involve specifying requirements and verifying software systems. The card swipe machine is a widely used point-ofsale terminal in supermarkets, medical centers, and shopping malls. Customers can easily make payments through these machines, which also provide detailed receipts of all transactions, including reversed transactions. This resolves cash management issues, improves customer service, and supports marketing. While multiple conventional machines are available in the market, they lack visual representations, making it difficult to understand their working mechanism without graphical representations. Deterministic finite automata (DFA) is a mathematical model that has limited states and moves from one state to another based on input and transition functions. This study proposes the use of the JFLAP software to create a mathematical model of card swipe machine transactions. The proposed model allows for viewing each processing step in a card swipe machine, offering a new approach to understanding their working mechanism.