Simulator

Drive every failure path on demand. Sandbox only — these endpoints do not exist in live.

Set NEXT_PUBLIC_API_URL and NEXT_PUBLIC_SANDBOX_KEY to point this screen at a running sandbox API. Buttons are disabled until then.
Payment intent
Deposit behaviours
Funds the intent precisely
Short of the total — lands in underpaid, never silently settles
Excess — funds the intent, flags the difference
No deposit; the funding clock expires the intent
Money arrives and trips review; the clock stops
The ordinary ACH return
The weeks-later reversal
Settlement
On-chain confirmation
The path merchants forget to handle
Activity
Fire a behaviour to watch the state machine move.