Health Savings Accounts (HSAs) are tax-advantaged savings accounts for medical expenses. Employees contribute pre-tax salary to HSAs, use funds for eligible medical costs, and keep unused balance for future years. Unlike FSAs (which expire), HSA funds roll over indefinitely. HSA platforms manage eligibility, contributions, claims processing, and tax reporting. They integrate with payroll systems (automatic deductions), health insurance systems (HDHP verification), and banking systems (card transactions, fund transfers).