Let any wallet or exchange pay into your Arc contract.

import { createDoorstep } from 'doorstep-arc';

const ds = createDoorstep();            // Arc mainnet

const invoice = ds.depositIntent({
  into: '0xYourVault',                // deposit(amount, to)
  beneficiary: customer,              // who gets credited
  refundTo: customer,                 // if it can't be delivered
  minimum: '25',
  expires: '7d',
  reference: 'inv-1042',
});

ds.depositAddress(invoice);           // show it, or a QR code
ds.toLink(invoice, { amount: '25' });  // a ready pay page
ds.watch(invoice, (e) => {            // waiting, landed, bounced
  if (e.type === 'landed') markPaid('inv-1042');
});

curl -X POST https://api.arcdoorstep.duckdns.org/v1/addresses \
  -H "Authorization: Bearer $DOORSTEP_KEY" \
  -H "content-type: application/json" \
  -d '{
    "into": "0xYourVault",
    "beneficiary": "0xCustomer",
    "refundTo": "0xCustomer",
    "amount": "25",
    "reference": "inv-1042",
    "webhookUrl": "https://yourapp.com/hooks/doorstep"
  }'

# 201 Created
{
  "address": "0x…",
  "payLink": "https://…/app/#i=…",
  "registered": true,
  "invoice": { "state": "unpaid", "remaining": "25" }
}

// Doorstep POSTs to your webhookUrl when a payment is delivered or returned
import crypto from 'node:crypto';

app.post('/hooks/doorstep', express.raw({ type: '*/*' }), (req, res) => {
  const ts = req.get('x-doorstep-timestamp');
  const expected = 'v1=' + crypto
    .createHmac('sha256', process.env.DOORSTEP_WEBHOOK_SECRET)
    .update(`${ts}.${req.body}`).digest('hex');
  if (req.get('x-doorstep-signature') !== expected) return res.sendStatus(401);

  const event = JSON.parse(req.body);
  // { type: 'payment.delivered', data: { reference: 'inv-1042', amount: '24.996', txUrl } }
  if (event.type === 'payment.delivered') markPaid(event.data.reference);
  res.sendStatus(200);
});

# Let an AI agent take payments, without being able to redirect them
claude mcp add doorstep -- node doorstep/agent/server.mjs

# Tools: create_payment_address, check_payment, deliver_payment
# Operator limits: allowed contracts, fee cap, longest deadline
DOORSTEP_ALLOWED_TARGETS=0xYourVault
DOORSTEP_MAX_FEE=0.02
DOORSTEP_MAX_DAYS=90

> Make a 25 USDC invoice into 0xYourVault for 0xCustomer,
  refunds to 0xCustomer, reference inv-1042.
> Before I pay this link, check it really credits me.

{
  "address": "0x…",
  "matchesExpectations": false,
  "mismatches": ["credits 0x000…dEaD, not 0xYou…"]
}