A comprehensive class diagram for a personal finance management system modeling core entities: User, Account, Transaction, Category, Budget, Goal, and Debt with their relationships and methods. The User class serves as the central entity, with one-to-many relationships to Account, Transaction, Budget, Goal, and Debt, while Transaction and Budget reference Category through foreign keys. Key operations include login/logout for User, syncBalance for Account, addTransaction and editTransaction for Transaction, calculateRemaining for Budget, updateProgress for Goal, and calculatePayoff for Debt. This architecture demonstrates proper entity modeling, primary and foreign key design, and method organization essential for building scalable fintech applications. Fork this diagram on Diagrams.so to customize entities, add new relationships, or export as .drawio, .svg, or .png for documentation and team collaboration. The design supports common personal finance workflows including multi-account management, transaction categorization, budget tracking, and debt payoff planning.