The unprotected happy path

This payment process charges a credit card and sends a receipt. Run it — it works perfectly.

But what happens when the card is declined? Or when the payment API times out? Or when the card number is invalid?

Run it and see

Press ▶ Play and watch the process complete successfully. In simulation mode, tasks always succeed.

In production, "Charge credit card" can fail. If it does and we have no error handling, the process instance gets stuck. No error path, no notification, no retry — just a process sitting there indefinitely.

> 💡 A process that only models success is called a "happy path only" design. It's one of the most common BPMN mistakes. Always ask: what can go wrong here?