wdk-payment-verifier

Server-side, read-only on-chain confirmation for self-custodial WDK Pay payments. A payment is a plain ERC-20 transfer of the settlement token (USDt) to the merchant; this library confirms one landed — Transfer(token, to = merchant, value ≥ due) with N confirmations — over JSON-RPC. No keys, no custody: the merchant only watches the chain. It's the Node/headless counterpart to the WooCommerce plugin's PHP verifier.

npm install wdk-payment-verifier

Verify a known transaction

import { PaymentVerifier } from 'wdk-payment-verifier'

const verifier = new PaymentVerifier({ rpcUrl: process.env.RPC_URL! })

const result = await verifier.verify(
  { tokenAddress: USDt, receivingAddress: merchant, amountBase: '19990000' }, // 19.99 USDt
  txHash,
  /* requiredConfirmations */ 5,
)
// result.status: 'confirmed' | 'pending' | 'failed'
if (result.status === 'confirmed') markOrderPaid(result)

Watch for an incoming payment (no hash yet)

const result = await verifier.watch(
  { tokenAddress: USDt, receivingAddress: merchant, amountBase: '19990000' },
  { requiredConfirmations: 5, timeoutMs: 15 * 60_000, pollIntervalMs: 5000 },
)

watch polls eth_getLogs for a matching Transfer to the recipient, then waits for confirmations; it resolves confirmed/failed, or pending (reason timeout) if the window elapses.

Pluggable provider

Pass rpcUrl (an ethers JsonRpcProvider is created lazily), an existing provider, or — for tests — any object implementing the minimal EvmReadProvider interface (getTransactionReceipt, getBlockNumber, getLogs). Nothing is hard-coded.

PaymentConfirmation carries status, txHash, blockNumber, confirmations, valueBase, and fromAddress so your order system has everything to reconcile.

License

MIT. Built with Tether WDK; not an official Tether product.