3. Autonomous DriftGuard Loop (x402-solana + hermes.swap.io)
Zero API keys stored in environment variables. Every paid call returns an on-chain X-PAYMENT-RESPONSE settlement hash verifiable on Solscan.
import { createX402Client } from 'x402-solana/client';
import { Connection, Keypair, PublicKey, VersionedTransaction } from '@solana/web3.js';
const SOL_MINT = 'So11111111111111111111111111111111111111112';
const USDC_MINT = 'EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v';
export async function rebalanceIfDrifted(rpc: Connection, treasury: Keypair, driftBps: number) {
// 1. Free check: 99.95% of 5-minute ticks cost $0.00 and zero API quota
if (Math.abs(driftBps) < 500) return { action: 'HOLD', apiSpentUsdc: 0 };
// 2. Initialize keyless x402 client (Swap.io feePayer sponsors payment gas!)
const x402 = createX402Client({
network: 'solana',
wallet: {
address: treasury.publicKey.toBase58(),
signTransaction: async (tx) => { tx.sign([treasury]); return tx; },
},
});
// 3. Paid Call #1 (0.003007 USDC, < $0.01): 402 Challenge -> USDC Micropayment -> Ranked Quotes
const quoteRes = await x402.fetch('https://hermes.swap.io/v1/swap/quote', {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify({
input: { token: SOL_MINT, amount: '10000000000', chainKey: 'sol' },
output: { token: USDC_MINT, chainKey: 'sol' },
userAddress: treasury.publicKey.toBase58(),
slippageBps: 50,
}),
});
const paymentReceipt1 = quoteRes.headers.get('X-PAYMENT-RESPONSE');
const { quotes } = await quoteRes.json();
const best = quotes[0];
// 4. Paid Call #2 (0.003007 USDC, < $0.01): Build unsigned VersionedTransaction
const buildRes = await x402.fetch('https://hermes.swap.io/v1/swap/build-tx', {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify({
provider: best.provider.key,
userAddress: treasury.publicKey.toBase58(),
chainKey: 'sol',
quoteResponse: best.providerQuote,
}),
});
const { transaction } = await buildRes.json();
const vtx = VersionedTransaction.deserialize(Buffer.from(transaction, 'base64'));
vtx.sign([treasury]);
const sig = await rpc.sendRawTransaction(vtx.serialize());
return { action: 'REBALANCED', swapSig: sig, paymentReceipt1, apiSpentUsdc: 0.006014 };
}