Screen a payee before paying: wallet risk check API (OFAC)

$0.01 per call · failed calls are never charged · no account or subscription: pay per call with a card key or USDC

Screen a payee before paying, trading or onboarding: one call vets an address on Base, Ethereum, Arbitrum or Optimism with an OFAC SDN match, account type and activity, USD holdings and, on Base, wallet or contract risk checks; add the payee's domain for its age and trust flags. One block, review or pass verdict with reasons. Screening aid, not legal advice or a security audit. Use before paying, trading with or onboarding an address.

When to use it

Screen a payee's EVM address before sending funds
Combine sanctions, account type, activity and USD holdings into one block, review or pass verdict
Let an agent decide whether to pay an address it was given

Guide: OFAC wallet screening API

Run it free (25 free calls) Buy credits by card (from $1) Example result (JSON)

Inputs

Name	Type	Description
`address` (required)	string	0x address to check
`chain`	string	Network: base (default), eth, arb or op. One of: `base`, `eth`, `arb`, `op`.
`domain`	string	Optional: the payee's domain or website URL, e.g. ethereum.org; adds domain age and trust flags

Request

Over HTTP, with a card key from /credits:

curl -H "Authorization: Bearer adt_…" "https://tools.funwords.eu/check/counterparty?address=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

Or one of your 25 free calls, no key:

curl "https://tools.funwords.eu/check/counterparty?address=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045&trial=1"

Without a key, the same URL answers 402 Payment Required with x402 and MPP terms, so an agent with a wallet pays per call in USDC (Base, Polygon, Arbitrum or Solana over x402; Base or Tempo over MPP) and retries.

Example result

{
  "address": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
  "chain": "base",
  "verdict": "pass",
  "reasons": [],
  "sanctions": {
    "listed": false,
    "matches": [],
    "listDate": "2026-10-17T20:15:00.000Z"
  },
  "account": {
    "type": "eoa",
    "riskLevel": "low",
    "riskFlags": [],
    "accountNonce": 1234
  },
  "contract": null,
  "domain": {
    "name": "ethereum.org",
    "trust": "high",
    "ageDays": 4100,
    "registeredAt": "2015-03-21T00:00:00Z",
    "flags": []
  },
  "holdings": {
    "totalUsd": 1234.56,
    "tokensChecked": 9
  },
  "limitations": [],
  "note": "Screening aid only: confirm any sanctions match against the official OFAC record; heuristics are not a security audit."
}

From an AI agent (MCP)

Add the MCP server to Claude, Cursor or any MCP client. This tool is check_counterparty, and the first 25 successful calls are free:

https://tools.funwords.eu/mcp

Questions

Which networks?

Base, Ethereum, Arbitrum and Optimism.

What does the verdict mean?

Block, review or pass, with the reasons that produced it. It is a screening aid, not a security audit.

How do I pay?

Each successful call costs $0.01; failed calls are not charged. The first 25 calls are free. Then pay with card credits (from $1; the key goes in an Authorization header or, for clients that can only fetch a URL, as api_key= in the URL) or per call in USDC over x402 or MPP. No account is needed.