Cashier terminal — shield the till.

Pick a checkout scenario below. The terminal posts the same POST /v1/transactions request a real retail integration would send, with a real card BIN, a real amount, and a real merchant id. ShieldTrade runs it through Capability Resolution → PSP Preflight (the deterministic card-BIN / amount / merchant evaluator) → Policy Engine and returns the same ALLOW / BLOCK / WARN decision the cashier would see on a real terminal.

Run a scenario to see the live decision.

What you are looking at

Decision is the only authoritative output. It is set by Hard Gate 2 (deterministic PSP preflight) and Tenant Policy.
Preflight reason is the deterministic verdict from the PSP preflight evaluator: CARD_BIN_DECLINED, AMOUNT_OVER_THRESHOLD, AMOUNT_HARD_LIMIT, or PSP_PREFLIGHT_PASS.
Hard Gate 2 BLOCK cannot be overridden by risk, ML, or operator approval. The cashier screen cannot display ALLOW when the evaluator returns BLOCK.
No card data leaves the terminal except the BIN. The demo forwards a masked string ("card:****-****-****-4242") plus metadata; the PSP preflight reads only the first 6 digits.