Cardinal Protection API
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cardinal://protect · api reference
Check payment risk before authorisation.
Send the proposed payment details to one endpoint. Use the returned action: ALLOW, REVIEW, or BLOCK.
Endpoint
Call Cardinal from a trusted server environment. Your API key authenticates the request, so it must never be shipped to a browser.
Store this key server-side. For web products, call Cardinal from your own backend and forward the verdict to the browser.
curl -X POST https://api.cardinalweb3.com/api/check-transaction \
-H "Content-Type: application/json" \
-H "x-api-key: <your-cardinal-api-key>" \
-d '{
"from_address": "0x1230000000000000000000000000000000000456",
"to_address": "0x0000000000000000000000000000000000000001",
"chain": "ethereum",
"token": "USDC",
"amount": 2500,
"transaction_type": "safe_send",
"expected_to_address": "0x0000000000000000000000000000000000000001",
"counterparty_name": "Atlas Building Materials FZE",
"intent_reference": "PO-DXB-2048",
"contract_verified": true,
"permissions": []
}'Verdict
Do not build product behavior from the score alone. Use recommended_action as the gate and use findings to explain the decision.
`risk_score` helps explain confidence. `recommended_action` decides whether the application continues, requests a review, or blocks before wallet approval.
{
"request_id": "req_8b2a...",
"risk_score": 18,
"risk_level": "LOW",
"network_valid": true,
"warnings": [],
"findings": [],
"recommended_action": "ALLOW",
"proof_of_decision": {
"status": "VERIFIED",
"record_version": "0.1",
"intent": {
"comparison": "MATCH",
"expected_to_address": "0x0000000000000000000000000000000000000001",
"proposed_to_address": "0x0000000000000000000000000000000000000001"
},
"evidence_codes": []
},
"checked_at": "2026-06-22T06:50:00.000Z"
}Payload
The request should be boring and explicit. Cardinal turns these transaction facts into explainable risk findings.