Machines pay per call. Receipts included.
Every endpoint below answers a plain request with HTTP 402 and an x402 v2 challenge: pay the stated USDC amount on Base to UnyKorn's treasury, retry with the payment header, get the answer and a settlement receipt. No account, no card, no signature, no custodian. The same catalog is machine-readable at /.well-known/x402.json.
Catalog (USDC on Base, eip155:8453)
| Endpoint | Price | What you get |
|---|---|---|
POST blockchainfraud.org/api/x402/screen | $0.25 | Address screen: OFAC sanctions list + Blockchain Fraud registry + format checks. Deterministic JSON. |
GET nil33.com/api/x402/kya/{name}.nil | $0.05 | Signed Know Your Athlete assertion (ES256 JWS), no throttle. Free rate-limited twin: /api/v1/verify/{name}.nil |
POST nil33.com/api/x402/shield | $0.10 | Contract Shield red-flag scan of pasted contract text. Pattern check, not legal review. |
POST nil33.com/api/x402/ask | $0.02 | NIL33 assistant answer with citations, no throttle. Free rate-limited twin: /api/ask |
GET nil33.com/api/x402/verify/{CODE} | $0.01 | NIL33 account record from the ledger. |
State, plainly
The challenge
Every endpoint returns a correct x402 v2 challenge (scheme exact, network eip155:8453, USDC, payTo the UnyKorn treasury, resource, price). Agents can discover and price the calls today.
Settlement on Base mainnet
Settlement runs through UnyKorn's own Genesis402 facilitator with the operator's key set; the manifest at /.well-known/x402.json reports settlement: live (checked 2026-10-07). No settled call has been published as a receipt on this site yet, so we say configured rather than proven. Flag F-48.
ERC-8004 identity of the payee
The payTo wallet is UnyKorn's Genesis402 rail, ERC-8004 agent #95721 on Base, with a public reputation record. A public on-chain identity, not a certification. Details on the transparency stack.
Free twins
Verification, the ledger, the assistant, and the browser scam check stay free with rate limits. The paid tier is the same call without the throttle, with a receipt.
How to pay (x402 v2)
GET https://nil33.com/api/x402/kya/jane-smith.nil
→ 402 {{ "x402Version": 2, "accepts": [{{ "scheme": "exact", "network": "eip155:8453", "maxAmountRequired": "50000", "asset": "0x8335…2913", "payTo": "0x7d9a…56DB", "resource": "…", "maxTimeoutSeconds": 60 }}] }}
# sign an EIP-3009 transferWithAuthorization for 0.05 USDC to payTo (any x402 client library does this)
GET … with header X-PAYMENT: <base64 x402 payload>
→ 200 {{ …assertion…, "settlement": {{ "transaction": "0x…", "network": "eip155:8453" }} }} + header X-PAYMENT-RESPONSE
The estate rail
UnyKorn also runs its own facilitator and gateway for the Genesis / Apostle Chain estate at genesis402.com (developer docs at dev.genesis402.com), priced internally in ATP. The endpoints on this page are priced in USDC so any counterparty can pay; ATP stays the internal unit.
Software and services only. Not a bank, broker-dealer, custodian, or adviser. No tokens. Prices are configuration and may change; the manifest is authoritative.