x402USDC on Base + Solana

x402-reputation

Reliability scores built from signed fulfillment attestations — each one tied to a payment that provably settled. Recency-decayed, per-attestor capped, and honest about its own confidence.

GitHub Tutorial API reference For agents skill.md .well-known/x402 
git clone https://github.com/nirholas/x402-reputation && cd x402-reputation
npm install && npm run dev

Pay on either rail

Every paid route answers with a dual-rail 402. The accepts array carries one EVM entry and one Solana entry; your client (or the checkout modal) picks whichever wallet it has. Each rail settles through its own facilitator — no single one handles both.

EVM · BASEUSDC on base-sepolia / base
0x40252CFDF8B20Ed757D61ff157719F33Ec332402
settled via x402.org/facilitator
SOLANAUSDC on solana-devnet / solana
WwwuGbqHrwF5RG89KhUbmRWEvjnRH9k5kVM5p7T3WwW
settled via facilitator.payai.network

How a score gets built

1 · PAYA buyer pays some merchant over x402 and the tx settles
→
2 · ATTEST$0.001 → signed record linking that tx to the outcome
→
3 · DECAYWeight halves every 30 days; per-attestor share capped at 25%
→
4 · SCORE$0.001 → signed reliability report with sample + confidence

Every attestation names the payment it is about, so the evidence behind a score is auditable: pull the sample from a report, check each payment.transaction on its own chain, and re-verify the signature offline.

Pricing

RoutePriceReturns
GET /score/:merchantId$0.001Reliability report (fulfillment rate, refund rate, sample attestations)
POST /attest$0.001Signed attestation record (links payment tx + outcome)
GET /merchantsfreeMerchant index with attestation counts
GET /attestations/:idfreeSigned attestation record
POST /verifyfree`{ valid: true | false }`
GET /healthfree`{ ok: true }`

Quickstart

import { wrapFetchWithPayment } from "x402-fetch";
import { privateKeyToAccount } from "viem/accounts";

const payFetch = wrapFetchWithPayment(fetch, privateKeyToAccount(process.env.PRIVATE_KEY));

// $0.001 — record what happened after a payment settled
await payFetch("http://localhost:4024/attest", {
  method: "POST", headers: { "content-type": "application/json" },
  body: JSON.stringify({
    merchantId: "osteria-fiorentina.example",
    outcome: "fulfilled",
    payment: { network: "solana-devnet", transaction: "5Kq7xJ2mN…", amount: "$0.75" },
    attestor: "WwwuGbqHrwF5RG89KhUbmRWEvjnRH9k5kVM5p7T3WwW",
    note: "Table was held, seated on time."
  })
});

// $0.001 — buy the merchant's record before you spend with them
const report = await (await payFetch(
  "http://localhost:4024/score/osteria-fiorentina.example"
)).json();

report.score;        // 88
report.confidence;   // "high"
report.sample;       // recent attestations, each naming its payment tx

Discovery