Built by us

PayGuard: OFAC sanctions check for crypto addresses

Before your agent or app sends money, check whether the receiving address is on the US Treasury OFAC SDN list. One call, no API key: pay per call in USDC on Base, Polygon, Arbitrum One or Solana over x402, use prepaid credits, or use the free preview and MCP server.

What it does

• Matches an address against every digital currency address published in the OFAC SDN list (official SDN.XML from sanctionslistservice.ofac.treas.gov). Our /v1/list check on 2026-10-23 showed 1,050 addresses across 106 SDN entries, list date 2026-10-21.
• Returns sanctioned true or false. The paid tier adds the matching SDN entity, its sanctions programs, the list date, the listed currency and a checksum check.
• Handles EVM, BTC, TRX, SOL, LTC, XMR and more. Matching is exact: EVM 0x and bech32 / cashaddr addresses are case-insensitive, base58 formats are case-sensitive.
• Every response carries the list date, so you can see how fresh the data is. Invalid input gets HTTP 400 before any payment is asked for.

Try it free

The preview tier is free and needs no wallet. Paste an address:

Or from a terminal:

# Lazarus Group address from the SDN list -> "sanctioned": true
curl -s "https://api.youraitools.co/payguard/v1/preview?address=0x098B716B8Aaf21512996dC57EB0615e2383E2f96"
# USDC contract on Base -> "sanctioned": false
curl -s "https://api.youraitools.co/payguard/v1/preview?address=0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"

The paid call and its 402 response

Call the paid route without paying and you get HTTP 402 with the payment terms in a PAYMENT-REQUIRED header. Any x402 client pays and retries automatically.

curl -i "https://api.youraitools.co/payguard/v1/address?address=0x098B716B8Aaf21512996dC57EB0615e2383E2f96"

What our unpaid probe got back on 2026-10-23 (header decoded, trimmed with …):

HTTP/2 402
payment-required: <base64 JSON, decoded below>

{
  "x402Version": 2,
  "error": "Payment required",
  "resource": { "url": "https://api.youraitools.co/payguard/v1/address", ... },
  "accepts": [
    { "scheme": "exact", "network": "eip155:8453",
      "amount": "1000",
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "payTo": "0x3c1A1E01e790Cd326495631B3b38Bd7068F08d6F",
      "maxTimeoutSeconds": 120,
      "extra": { "name": "USD Coin", "version": "2" } },
    { "scheme": "exact", "network": "eip155:137", "amount": "1000", ... },
    { "scheme": "exact", "network": "eip155:42161", "amount": "1000", ... },
    { "scheme": "exact", "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
      "amount": "1000",
      "payTo": "FH73WbbUe2UyNzfy72MJs5nT3NxyDf9GrqE7kzjL2Jte", ... }
  ]
}

Install as an MCP server

The hosted MCP server at https://api.youraitools.co/payguard/mcp exposes screen_address at the free preview tier. The npm package @agentgate-builder/payguard (MIT) runs a local stdio server with the list bundled, exposing screen_address and screen_addresses. It needs Node.js 18 or later and gives preview results by default, and full paid results only if you set a PAYGUARD_X402_PRIVATE_KEY of your own (it then pays $0.001 per address).

Claude Desktop

Add to claude_desktop_config.json. Remote (via mcp-remote):

{
  "mcpServers": {
    "payguard": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://api.youraitools.co/payguard/mcp"]
    }
  }
}

Or local:

{
  "mcpServers": {
    "payguard": {
      "command": "npx",
      "args": ["-y", "-p", "@agentgate-builder/payguard", "payguard-mcp"]
    }
  }
}

Claude Code

# remote (hosted, preview tier)
claude mcp add --transport http payguard https://api.youraitools.co/payguard/mcp

# or local stdio server (bundled list snapshot, runs offline)
claude mcp add payguard -- npx -y -p @agentgate-builder/payguard payguard-mcp

Cursor

Add to .cursor/mcp.json (project) or ~/.cursor/mcp.json (global). Remote:

{
  "mcpServers": {
    "payguard": {
      "url": "https://api.youraitools.co/payguard/mcp"
    }
  }
}

Or local:

{
  "mcpServers": {
    "payguard": {
      "command": "npx",
      "args": ["-y", "-p", "@agentgate-builder/payguard", "payguard-mcp"]
    }
  }
}

These configs match the MIT agentgate-examples repo (folder mcp/). We ran the local server (npm 0.2.0) on 2026-10-23: tools/list returned both tools, and the Lazarus Group address came back SANCTIONED.

Pricing

Checked via our 402 probe on 2026-10-23: /v1/address asks for 1000 (0.001 USDC) and /v1/batch for 10000 (0.01 USDC), x402 v2, scheme exact, on Base (eip155:8453), Polygon, Arbitrum One and Solana. payTo 0x3c1A1E01e790Cd326495631B3b38Bd7068F08d6F on the EVM networks and FH73WbbUe2UyNzfy72MJs5nT3NxyDf9GrqE7kzjL2Jte on Solana (our own wallets). x402 v1 terms (Base only) are also offered. No signup or API key. Prepaid credits work too.

API and links

• API base: https://api.youraitools.co/payguard (also at payguard.agentgate.workers.dev)
• API reference (OpenAPI) · x402 manifest · list info
• Source code (MIT) · npm package
• Full integration guide (response fields, paying from code, FAQ)
• PayGuard on Built by us (probe details) · sanctions screening APIs compared

Limits and compliance disclaimer

More from us: all our tools · CounterpartyCheck for a wider pre-payment check · x402-enable your own API