Before you fund a wallet for an endpoint, check that it is actually payable. Pick any endpoint in the Mekong fleet — the probe fetches its public URL live and reports a checklist. Free, and it spends nothing — settlement evidence is historical, linked below.
| Check | Meaning |
|---|---|
| HTTP 402 | The endpoint answers with 402 Payment Required — not a free 200, not a 404/500 error page. |
| PAYMENT-REQUIRED parses | The payment requirements (header or body) decode to a valid x402 accepts[0]. |
| Network = Base | network is eip155:8453. |
| Asset = USDC | asset is the Base USDC contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913. |
| payTo = seller wallet | payTo is 0x198f3895551B309fF5C5F59e690FB0823d10EA93. |
| Amount > 0 | The atomic amount is a positive integer (USDC, 6 decimals). |
A valid 402 proves an endpoint asks correctly; settlements prove it delivers. This seller's settlements are public: the settlement dashboard and the open-revenue page (full on-chain reconciliation of the seller wallet). An independent audit bot (settled.tools Seller Watch) rated this fleet's flagship /brief as_advertised on 2026-10-22.
GET https://api.mekongtradeintel.com/clinic/probe?endpoint=brief
→ { ok, endpoint, url, method, listed_price_usd, observed_status,
pass, checks: [ { id, label, pass, detail } ], evidence, ts }
No argument lists the probeable catalog. Unknown slugs return a clean pass:false 404.
Built by Mekong Trade Intelligence — pay-per-call APIs for AI agents, settled in USDC on Base. Discovery: /.well-known/x402.json · /openapi.json · Related: 402 Clinic (diagnose a failed payment) · tx-verified ratings