Live decision Counterfactual explorer Sandbox checkout Policy battle Adversary arena Network view Model card

Score it, explain it, find the yes.

Pick a real test-set payment or build your own. The same request returns a coarse buyer view and a full analyst view.

Sample payments
Custom payment

Choose a payment to see the decision.

What would make this a yes?

Move only what a buyer can change: how much is paid now, when, and with which card. Everything else (device, history, graph signals) stays fixed.

Paid now100%
Goes through later0 h
Funding source
Original
—
With your changes
—

Approval line: —. Scores are the model's calibrated fraud probability; counterfactuals describe the model, not causal truth.

Engine's cheapest options

Decision to PayPal, end to end.

The engine scores the buyer before PayPal opens, then runs its plan on the authorization: capture, verify, review, or a "yes, if". PayPal sandbox only: use a sandbox personal account, no real money moves.

1 · Product
2 · Who is buying
3 · What the buyer sees

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What the merchant sees

When the world changes, friction matters.

Every policy replays the same test stream. Halfway through, attackers learn to pass one-time passcodes and step-up's catch rate drops from 85% to 40%.

An attacker that keeps probing.

A black-box attacker controls amount (keeping at least half), timing (up to 24h) and funding source. Each round, its successful attacks are added to training.

E6 · evasion by retraining round (line: clean PR-AUC)
E7 · evasion vs. query budget on the deployed model

Perturbations happen in feature space, which is a simplification; real attackers face stricter constraints. Exact scores and counterfactuals are analyst-only and rate-limited for this reason.

One device, many cards.

Shared-entity features count how many distinct cards have touched a device, email domain or billing region so far, causally, in time order. This is the ring behind the "ring" sample.

Model card.

Detector quality, calibration, the value of graph features, counterfactual quality and a fairness check, all on the held-out, later-in-time test split.

E1 · detector (test)
E2 · reliability after isotonic calibration
E3 · graph features & E4 · counterfactuals
Fairness · false-positive rate by segment