Counterparty check

Counterparty check in one call. Send a company or person name, a domain, an EVM wallet address, or any mix; returns one report with a status per check: OFAC sanctions (name and wallet), SEC EDGAR and GLEIF company records (name), domain registration, DNS and TLS, and email authentication (domain); each check that returns data cites sources and retrieval times. Use before paying or onboarding a party. A screening aid, not a compliance determination. Failed calls are not charged.

$0.03per successful call

USDC on Basepaid over x402

Freewhen a call fails

Try one call free

5 free calls a day per address, no payment. Demo inputs travel in the web address, which logs can record, so use the paid route for anything private.

The result appears here.

Example

Request body for POST /v1/counterparty-check:

{
  "name": "Banco Nacional de Cuba"
}

Response:

{
  "query": {
    "name": "Banco Nacional de Cuba",
    "domain": null,
    "address": null
  },
  "complete": true,
  "summary": {
    "sanctions_name": "match",
    "sanctions_address": "not_applicable",
    "sec": "unknown",
    "gleif": "unknown",
    "domain": "not_applicable",
    "email_auth": "not_applicable"
  },
  "checks": {
    "sanctions_name": {
      "status": "match",
      "result": {
        "query": "Banco Nacional de Cuba",
        "query_type": "name",
        "matches": [
          {
            "uid": "306",
            "name": "BANCO NACIONAL DE CUBA",
            "matched_name": "BANCO NACIONAL DE CUBA",
            "type": "entity",
            "programs": [
              "CUBA"
            ],
            "list": "OFAC SDN",
            "score": 1.0,
            "remarks": "a.k.a. 'BNC'."
          }
        ],
        "lists": [
          "OFAC SDN",
          "OFAC Consolidated (non-SDN)"
        ],
        "list_downloaded_at": "2026-10-22T03:15:04+00:00",
        "screened_at": "2026-10-22T09:00:00+00:00"
      },
      "provenance": {
        "lists": [
          {
            "name": "OFAC SDN",
            "files": [
              "SDN.CSV",
              "ALT.CSV",
              "SDN.XML"
            ],
            "entries": 19471,
            "refreshed_at": "2026-10-22T03:15:04+00:00"
          },
          {
            "name": "OFAC Consolidated (non-SDN)",
            "files": [
              "CONS_PRIM.CSV",
              "CONS_ALT.CSV"
            ],
            "entries": 486,
            "refreshed_at": "2026-10-22T03:15:04+00:00"
          }
        ],
        "crypto_addresses": {
          "covered": true,
          "addresses": 1050,
          "match": "exact",
          "from": "Digital Currency Address ids in SDN.XML (OFAC SDN list)"
        },
        "sources": [
          {
            "file": "SDN.CSV",
            "url": "https://sanctionslistservice.ofac.treas.gov/api/PublicationPreview/exports/SDN.CSV",
            "retrieved_at": "2026-10-22T03:15:04+00:00",
            "sha256": "6167e477d8a33cc18eeec1149e65fd0ce7430722256e0feb0277173fefdb153a"
          },
          {
            "file": "ALT.CSV",
            "url": "https://sanctionslistservice.ofac.treas.gov/api/PublicationPreview/exports/ALT.CSV",
            "retrieved_at": "2026-10-22T03:15:04+00:00",
            "sha256": "4d48fba6cf5f7d6abfb35e695f453297870a7a56568ceae968f06d04701b0047"
          },
          {
            "file": "CONS_PRIM.CSV",
            "url": "https://sanctionslistservice.ofac.treas.gov/api/PublicationPreview/exports/CONS_PRIM.CSV",
            "retrieved_at": "2026-10-22T03:15:04+00:00",
            "sha256": "a6e9c460a6f6d9bda9b3b2e6d909437a32b7629dede0e897bc382a24d86b499e"
          },
          {
            "file": "CONS_ALT.CSV",
            "url": "https://sanctionslistservice.ofac.treas.gov/api/PublicationPreview/exports/CONS_ALT.CSV",
            "retrieved_at": "2026-10-22T03:15:04+00:00",
            "sha256": "90adf60559576e89ce40ca68fd4256632930887d9351139e29b7f1c36bc684fc"
          },
          {
            "file": "SDN.XML",
            "url": "https://sanctionslistservice.ofac.treas.gov/api/PublicationPreview/exports/SDN.XML",
            "retrieved_at": "2026-10-22T03:15:04+00:00",
            "sha256": "bf92a04e60b4b2362d45490e5142e47b687c2ebb5898da6bc71b697602016e6e"
          }
        ],
        "freshness": "lists downloaded daily; screening is refused when any list is over 3 days old"
      }
    },
    "sanctions_address": {
      "status": "not_applicable",
      "detail": "send address to screen a wallet"
    },
    "sec": {
      "status": "unknown",
      "detail": "no matching SEC filer"
    },
    "gleif": {
      "status": "unknown",
      "detail": "no LEI record matched; many companies have no LEI, so this does not show that the company does not exist",
      "result": {
        "records": [],
        "source": "GLEIF LEI data (CC0). Not endorsed by GLEIF."
      },
      "provenance": {
        "sources": [
          {
            "url": "https://api.gleif.org/api/v1/lei-records?filter%5Bentity.legalName%5D=Banco+Nacional+de+Cuba&page%5Bsize%5D=3",
            "retrieved_at": "2026-10-22T09:00:00+00:00",
            "sha256": "dbfa44832c3e12f5ab23a2519dde3bcbe2873c99898682196d3fd06e529b910a"
          },
          {
            "url": "https://api.gleif.org/api/v1/fuzzycompletions?field=entity.legalName&q=Banco+Nacional+de+Cuba",
            "retrieved_at": "2026-10-22T09:00:00+00:00",
            "sha256": "ea1e4b0997719419e0479e692a4c3f83badeef53dd283d0e9eec8dddc353919d"
          }
        ],
        "freshness": "read live from the GLEIF API and cached up to 24 hours"
      }
    },
    "domain": {
      "status": "not_applicable",
      "detail": "send domain to check registration, DNS and TLS"
    },
    "email_auth": {
      "status": "not_applicable",
      "detail": "send domain to check SPF, DMARC and DKIM"
    }
  },
  "checked_at": "2026-10-22T09:00:00+00:00",
  "notice": "Screening aid, not a compliance determination. No match does not clear a party. Source: US Treasury OFAC lists (US government work)."
}

Call it with x402

Any x402 client works: call, read the price in the 402, pay, call again. With curl you see the terms:

curl -i -X POST https://quantagentshop.com/v1/counterparty-check \
  -H 'content-type: application/json' \
  -d '{"name": "Banco Nacional de Cuba"}'

HTTP/1.1 402 Payment Required
PAYMENT-REQUIRED: (the terms below, base64)

{"x402Version": 2, "error": "payment_required", "accepts": [{"scheme": "exact", "network": "eip155:8453", "amount": "30000", "payTo": "0x4d8d8D4f04512029172e0176744Eec4AE5238309", ...}], ...}

# amount is in millionths of a USDC. Pay one of accepts, then send the same request again with the PAYMENT-SIGNATURE header.

In JavaScript, @x402/fetch pays and retries for you:

// npm install @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { ExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const signer = privateKeyToAccount(process.env.EVM_PRIVATE_KEY); // a wallet holding a little USDC
const client = new x402Client().register("eip155:*", new ExactEvmScheme(signer));
const fetchWithPayment = wrapFetchWithPayment(fetch, client);

const res = await fetchWithPayment("https://quantagentshop.com/v1/counterparty-check", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({"name": "Banco Nacional de Cuba"}),
});
console.log(await res.json());

Use it over MCP

Add the remote MCP server, then call quantagentshop_counterparty_check. The free quantagentshop_quote tool gives the price and pay-to address and checks your arguments before you pay.

{
  "mcpServers": {
    "quantagentshop": {
      "url": "https://quantagentshop.com/mcp"
    }
  }
}

Terms, privacy and sources are on the policies page; live figures on the status page.