Should my agent pay this seller?

Before an agent pays an x402 endpoint it has not used before, Factline reads the seller's own 402 challenge, screens every wallet it asks to be paid in against the OFAC sanctions list, checks how old the domain is, looks up how often the seller answered Factline's daily probes, and, if you name the company behind it, checks the company register and the EU, UN, UK and US sanctions lists. The answer is allow, review or deny.

Try it

# free preview
curl "https://factline.dev/v1/payee/check/preview?url=https://factline.dev/v1/kyb/check"

# paid (x402 on Base or Solana, or an API key)
curl -H "x-api-key: fl_live_..." "https://factline.dev/v1/payee/check?url=https://factline.dev/v1/kyb/check"

MCP tool: x402_payee_check on https://factline.dev/mcp/kyc.

Use it as a trust provider

Every answer carries a trust block (decision, score, evidence, ttl) in the shape proposed for x402 trust providers, so a wallet or SDK can call it before it signs a payment:

const r = await fetch("https://factline.dev/v1/payee/check?url=" + encodeURIComponent(target), { headers: { "x-api-key": KEY } });
const { trust } = await r.json();
if (trust.decision === "deny") throw new Error("payee failed screening");
if (trust.decision === "review") askUser(trust.evidence);
// cache the decision for trust.ttl seconds

What is checked

Automated check of public signals, not a guarantee. Wallet screening is an exact match against OFAC-listed addresses, without blockchain analytics. Free list of sellers with uptime: x402 Seller Health Index.