Swimlanes.io is a free webapp for making sequence diagrams. You simply edit the text on the left and the diagram is updated in real time. You can download your sequence diagrams as images or distribute with a link.
autonumber Title: ATM Flow _: ** Withdraw cash ** USER -> ATM: Insert card ATM -> BANK: Verify card ...: {fas-spinner} _: ** Card validation process ** if: if the card is valid ATM <-- BANK: Card ok USER <- ATM: Request PIN USER -> ATM: Enter PIN else: **else** ATM <-- BANK: Card invalid USER <- ATM: Eject card end _: ** PIN validation process ** USER --> ATM: Enter PIN ATM -> BANK: Verify PIN if: if PIN valid ATM <-- BANK: PIN ok USER <- ATM: Enter amount else: **else** ATM <- BANK: PIN invalid USER <- ATM: Eject card end _: ** Transaction process** USER --> ATM: Enters amount ATM -> BANK: Initiate transaction BANK -> BANK ACCOUNT: Sufficient funds? note: Check particular bank account has sufficient funds before doing the transaction if: if funds sufficient BANK <-- BANK ACCOUNT: Has funds BANK -> BANK ACCOUNT: Withdraw amount BANK <-- BANK ACCOUNT: withdraw success ATM <-- BANK: Transaction complete USER <- ATM: Dispense Cash else: **else** BANK <-- BANK ACCOUNT: Insufficient fund ATM <-- BANK: Transaction unsuccessful end USER <- ATM: Eject card