Checkout/ACH Payments

ACH Payments

Accept bank transfers with lower fees via CoinFlow's ACH infrastructure

Why ACH?

ACH payments have significantly lower fees than card payments (typically 0.8% vs 2.9%), making them ideal for high-value transactions, round-up micro-payments, and recurring billing. Hedge Payments uses CoinFlow as the underlying ACH provider with optional USDC instant settlement.

Fee Comparison

Payment Method	Fee	Settlement
Credit/Debit Cards	2.9% + $0.30	Instant
ACH + USDC Settlement	0.8% (max $5)	Instant (on Solana)
ACH + USD Settlement	0.8% (max $5)	3 business days

How ACH Works with Hedge

The ACH flow has two phases: a one-time bank account linking step, and then per-transaction ACH debits.

Create Customer

POST /api/customer -- Register the consumer with CoinFlow

Get Session Key

GET /api/auth/session-key -- Generate a 24-hour scoped token

Link Bank Account

POST /api/customer/v2/bankAccount -- Tokenize the consumer's bank (one-time)

Submit ACH Checkout

POST /api/checkout/ach/{merchantId} -- Debit the consumer's bank account

Handle Webhooks

ACH Initiated > ACH Batched > Settled (or ACH Returned / ACH Failed)

Step 1: Get a Session Key

Generate a session key scoped to a specific consumer. Session keys are valid for 24 hours.

Get Session Keybash

curl -X GET https://api-sandbox.coinflow.cash/api/auth/session-key \
  -H "Authorization: YOUR_COINFLOW_API_KEY" \
  -H "x-coinflow-auth-user-id: consumer-123" \
  -H "Content-Type: application/json"

Response:

Session Key Responsejson

{
  "key": "eyJhbGciOiJIUzI1NiIs..."  // Note: field is "key", not "sessionKey"
}

Important

The response field is key, not sessionKey. Session keys expire after 24 hours and must be regenerated.

Step 2: Link Bank Account

Link a consumer's bank account for ACH debits. This is a one-time step per consumer. All fields including name and address are required by the CoinFlow API.

Link Bank Accountbash

curl -X POST https://api-sandbox.coinflow.cash/api/customer/v2/bankAccount \
  -H "x-coinflow-auth-wallet: consumer-123" \
  -H "Content-Type: application/json" \
  -d '{
    "type": "checking",
    "email": "user@example.com",
    "alias": "My Checking",
    "firstName": "Jane",
    "lastName": "Doe",
    "routingNumber": "110000000",
    "account_number": "000123456789",
    "address1": "123 Main St",
    "city": "Austin",
    "state": "TX",
    "zip": "78701"
  }'

Response: 204 No Content on success.

Required Fields

Parameter	Type	Required	Description
`type`	string	Required	"checking" or "savings"
`email`	string	Required	Consumer's email address
`firstName`	string	Required	Account holder first name
`lastName`	string	Required	Account holder last name
`routingNumber`	string	Required	9-digit ABA routing number
`account_number`	string	Required	Bank account number
`address1`	string	Required	Street address
`city`	string	Required	City
`state`	string	Required	2-letter state code
`zip`	string	Required	5-digit ZIP code

Header note

Bank account linking uses x-coinflow-auth-wallet as the auth header (not Authorization). This is the consumer's external ID.

Step 3: Submit ACH Checkout

Once a bank account is linked, submit an ACH debit to pull funds from the consumer's bank account.

ACH Checkout Requestbash

curl -X POST https://api-sandbox.coinflow.cash/api/checkout/ach/{merchantId} \
  -H "x-coinflow-auth-session-key: SESSION_KEY_HERE" \
  -H "Content-Type: application/json" \
  -d '{
    "subtotal": { "cents": 63 },
    "token": "BANK_ACCOUNT_TOKEN",
    "settlementType": "USDC",
    "webhookInfo": {
      "roundUpId": "txn_abc123",
      "merchantId": "your-merchant-id"
    }
  }'

Response:

ACH Checkout Responsejson

{
  "paymentId": "pay_xyz789"  // Note: field is "paymentId", not "id"
}

Checkout Fields

Parameter	Type	Required	Description
`subtotal`	object	Required	Object with "cents" (integer) and optional "currency"
`token`	string	Required	Bank account token from the linking step
`settlementType`	string	Optional	"USDC" (instant) or "Credits" or "Bank" (3 business days)
`webhookInfo`	object	Optional	Arbitrary JSON passed through to webhook payloads
`jwtToken`	string	Optional	Server-signed JWT to prevent client-side amount tampering

ACH Payment Status Flow

ACH Initiated

Payment submitted to bank -- immediate

ACH Batched

Bank accepted and processing -- same day or next business day

Settled

Funds delivered to merchant -- instant (USDC) or 1-3 business days (USD)

Failure states

ACH Returned -- Bank returned the funds (2-5 business days after batch). Reasons: insufficient funds, account closed, unauthorized debit.

ACH Failed -- Bank rejected the debit (1-2 business days). Invalid account or routing number.

Handle ACH Webhooks

CoinFlow sends webhook events as the ACH payment progresses. Validate the Authorization header against your Webhook Validation Key.

Webhook Payloadjson

{
  "eventType": "ACH Batched",
  "category": "ach",
  "created": "2026-03-24T14:30:00Z",
  "data": {
    "id": "pay_xyz789",
    "webhookInfo": { "roundUpId": "txn_abc123" },
    "subtotal": { "cents": 63, "currency": "USD" },
    "fees": { "cents": 0, "currency": "USD" },
    "total": { "cents": 63, "currency": "USD" },
    "merchantId": "your-merchant-id",
    "customerId": "consumer-123"
  }
}

Node.js Webhook Handlerjavascript

app.post('/webhooks/coinflow', async (req, res) => {
  // Validate webhook authenticity
  const webhookKey = req.headers['authorization']
  if (webhookKey !== process.env.COINFLOW_WEBHOOK_KEY) {
    return res.status(401).send('Unauthorized')
  }

  // Deduplicate (CoinFlow may send duplicates)
  const eventId = req.body.data?.id
  if (await isAlreadyProcessed(eventId)) {
    return res.status(200).json({ status: 'duplicate' })
  }

  const { eventType, data } = req.body

  switch (eventType) {
    case 'ACH Initiated':
      await updateTransaction(data.webhookInfo.roundUpId, 'INITIATED')
      break

    case 'ACH Batched':
      await updateTransaction(data.webhookInfo.roundUpId, 'PROCESSING')
      break

    case 'Settled':
      await updateTransaction(data.webhookInfo.roundUpId, 'SETTLED')
      break

    case 'ACH Returned':
      await handleReturn(data)
      break

    case 'ACH Failed':
      await handleFailure(data)
      break
  }

  // Must respond within 5 seconds
  res.status(200).json({ status: 'accepted' })
})

Webhook Retry Policy

CoinFlow retries until your server returns 200 OK, or 36 hours elapse
Your server must respond within 5 seconds or the request times out
Webhooks are not exactly-once -- always deduplicate on data.id

Merchant-Initiated Transactions (Recurring)

After a consumer's first ACH checkout, subsequent debits can be initiated server-side using the original paymentId. This is ideal for recurring round-ups where the consumer doesn't need to re-authenticate each time.

Merchant-Initiated Transactionbash

curl -X POST https://api-sandbox.coinflow.cash/api/checkout/merchant-initiated-transaction \
  -H "x-coinflow-auth-user-id: consumer-123" \
  -H "Content-Type: application/json" \
  -d '{
    "subtotal": { "cents": 47, "currency": "USD" },
    "originalPaymentId": "pay_xyz789",
    "settlementType": "USDC"
  }'

Rate limit

5 transactions per originalPaymentId per 90-second window. Exceeding this returns 429 Too Many Requests.

Sandbox Testing

Sandbox base URL

https://api-sandbox.coinflow.cash

In sandbox mode, CoinFlow accepts any valid-format routing and account numbers. No real bank verification occurs.

Scenario	Routing Number	Account Number	Result
Success	110000000	000123456789	ACH Settled
Any valid format	Any 9 digits	Any digits	Works in sandbox

Plaid Sandbox (if using SDK)

Username

user_good

Password

pass_good

Error Handling

HTTP Code	Meaning	Action
423	Customer blocked	5 failed attempts -- contact support
428	Re-verification required	Consumer must re-verify bank account
429	Rate limited	MIT: max 5 per originalPaymentId per 90s
451	KYC verification required	Consumer must complete identity verification

What's Next?

SideBet Round-Ups

Integrate automated round-ups for sportsbook transactions

Webhooks Guide

Handle ACH events in real-time

Settlement Options

USDC instant vs USD standard settlement

SideBet API Reference

Complete endpoint documentation for round-ups