Develop with Atum SDK

npm install @atumlabs/mppx-atum-escrow mppx zod ethers

import { Mppx } from "mppx/client";
import { ethers } from "ethers";
import { registerClient } from "@atumlabs/mppx-atum-escrow/client";

// The source account is derived from your key. The server rejects a credential whose
// signature does not recover to it, so the two must match.
const account = new ethers.Wallet(PRIVATE_KEY).address;
const method = registerClient({ signer: { privateKey: PRIVATE_KEY }, account });

const mppx = Mppx.create({ methods: [method] });

// Call it like fetch — your agent's tool-call code doesn't need to branch
// on which payment method the resource ends up charging.
const res = await mppx.fetch("https://merchant.example/paid");

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What’s happening

1. registerClient builds an atum-escrow client method for mppx — the same Method.toClient() idiom every MPP payment method (Stripe, Tempo) implements. The source account is derived from your key.
2. When the resource server returns a 402 with a challenge naming atum-escrow, mppx hands it to this method’s createCredential.
3. createCredential reads the challenge’s corridor terms (destination, deadlines, settlement vault/proxy/role addresses), checks them (see below), builds the Atum PaymentRequest, and signs the source-side Permit2 authorization with your key.
4. mppx attaches the resulting credential to the retried request as Authorization: Payment, and returns the 200 with a Payment-Receipt header.

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Next steps