Instant Payments API

Accept instant SEPA payments from your customers with zero chargebacks, no rolling reserves, and same-day settlement. This API lets you create checkout sessions and receive payment confirmations.

Overview

The Dapit Instant Payments API enables merchants to accept EUR payments via SEPA Instant Credit Transfer. Instead of credit cards, your customers pay directly from their bank account (Wise, Revolut, or any EUR-enabled bank). Payments settle in under 10 seconds and are irrevocable — no chargebacks.

Base URL:

https://www.maxafi.com/api/gateway/gateway.php

Payment Flow

The customer never leaves your website. When they choose "Pay with Instant Payments" at your checkout, your server talks to our API behind the scenes.

Authentication

All API requests require your merchant API key. Include it in the request header:

X-Gateway-Key: your_api_key_here

Your API key is provided during merchant onboarding. Keep it secret — it authenticates all requests to our API on your behalf.

Quick Start — Option A: API Integration

Your developer adds Instant Payments as a payment option on your existing checkout page. The customer never leaves your website.

Step 1: Customer selects "Pay with Instant Payments" on your checkout

Your checkout page already has credit card, ACH, etc. Add an "Instant Payments" button alongside them. When they click it, your server creates a session:

Copy// YOUR SERVER — Create a session when customer chooses Instant Payments
const response = await fetch('https://www.maxafi.com/api/gateway/gateway.php?action=create_session', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'X-Gateway-Key': 'your_api_key_here'
  },
  body: JSON.stringify({
    amount: 49.99,
    currency: 'EUR',
    items: [
      { name: 'Premium Game Credits', qty: 1, price: 49.99, total: 49.99 }
    ],
    callback_url: 'https://yoursite.com/webhooks/dapit'
  })
});

const session = await response.json();
// session.session_token → save this (you'll need it for polling)
// Now call create_invoice to get the payment details...

Step 2: Get payment details and display on YOUR page

Copy// YOUR SERVER — Get the IBAN, beneficiary, and reference number
const invoice = await fetch('https://www.maxafi.com/api/gateway/gateway.php?action=create_invoice', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ token: session.session_token })
}).then(r => r.json());

// Display these on YOUR checkout page:
// invoice.beneficiary_name → "Longemalle Trustees OU"
// invoice.iban             → "LT913740020058585210"
// invoice.reference_number → "DP-260330-XA6HSX"
// invoice.amount           → 49.99
// invoice.invoice_number   → "INV-260330-04821"
//
// Tell the customer:
// 1. Open your banking app (Wise, Revolut, etc.)
// 2. Send €49.99 to beneficiary "Longemalle Trustees OU"
// 3. IBAN: LT913740020058585210
// 4. Reference: DP-260330-XA6HSX
// 5. Click "I've Sent the Payment" button on your page

Step 3: Customer clicks "I Paid" — start polling

Copy// YOUR PAGE (JavaScript) — When customer clicks "I Paid"

// First, tell our API the customer says they paid
await fetch('https://www.maxafi.com/api/gateway/gateway.php?action=confirm_paid', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ token: sessionToken })
});

// Then poll every 7 seconds until payment is confirmed
const pollInterval = setInterval(async () => {
  const check = await fetch('https://www.maxafi.com/api/gateway/gateway.php?action=check_payment', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ token: sessionToken })
  }).then(r => r.json());

  if (check.status === 'confirmed') {
    clearInterval(pollInterval);
    // 🎉 Full payment confirmed!
    showPaymentSuccess(check.total_paid, check.invoice_amount);

  } else if (check.status === 'partial') {
    clearInterval(pollInterval);
    // ⚡ Partial payment — show receipt + remaining balance
    showPartialPayment(check.total_paid, check.amount_remaining, check.payments);
    // When customer sends remaining: call confirm_paid again, restart polling

  } else if (check.status === 'overpaid') {
    clearInterval(pollInterval);
    // 💰 Overpayment — order confirmed, refund will be processed
    showOverpaid(check.total_paid, check.overpaid_amount, check.refund_net, check.refund_fee);

  } else if (check.status === 'timeout') {
    clearInterval(pollInterval);
    showPaymentRetry();
  }
  // 'pending' — keep polling
}, 7000);

Step 4: Receive webhook confirmation (your server)

Copy// YOUR SERVER — Webhook endpoint receives POST when payment is confirmed
// Fires for both exact and overpayments (not for partial — only when fully paid)
app.post('/webhooks/dapit', (req, res) => {
  const { event, merchant_order_id, invoice_amount, amount_paid,
          overpaid_amount, refund_amount, refund_fee } = req.body;

  if (event === 'payment.confirmed') {
    // ✅ Payment confirmed! Update your order database.
    console.log(`Order ${merchant_order_id} paid: €${amount_paid} of €${invoice_amount}`);

    if (overpaid_amount > 0) {
      // Customer overpaid — refund of €(overpaid - fee) will be processed
      console.log(`Overpaid by €${overpaid_amount}. Refund: €${refund_amount} (fee: €${refund_fee})`);
    }

    // Mark order as paid, send confirmation email, trigger fulfillment
  }

  res.status(200).json({ received: true });
});

Quick Start — Option B: Hosted Checkout

If you don't have a developer or want the simplest possible integration, use our hosted checkout page. You just create a session and redirect — we handle the entire payment UI.

Copy// YOUR SERVER — Create session and redirect customer to our hosted page
const session = await fetch('https://www.maxafi.com/api/gateway/gateway.php?action=create_session', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'X-Gateway-Key': 'your_api_key_here'
  },
  body: JSON.stringify({
    amount: 49.99,
    currency: 'EUR',
    items: [{ name: 'Premium Game Credits', qty: 1, price: 49.99, total: 49.99 }],
    callback_url: 'https://yoursite.com/webhooks/dapit'
  })
}).then(r => r.json());

// Redirect customer to our hosted checkout
res.redirect('https://www.maxafi.com' + session.checkout_url);
// Customer sees: your merchant name, invoice, IBAN, reference, "I Paid" button
// When confirmed, we POST to your callback_url

Create Session

{
  "success": true,
  "session_id": 42,
  "session_token": "a1b2c3d4e5f6...",
  "checkout_url": "/checkout/pay.html?session=a1b2c3d4e5f6...",
  "expires_at": "2026-03-30 23:30:00",
  "amount": 49.99,
  "currency": "EUR",
  "merchant_order_id": "ORD-12345"
}

Create Invoice

{
  "success": true,
  "reference_number": "DP-260330-XA6HSX",
  "invoice_number": "INV-260330-04821",
  "amount": 49.99,
  "currency": "EUR",
  "iban": "LT913740020058585210",
  "beneficiary_name": "Longemalle Trustees OU",
  "account_name": "Dapit Financial Infrastructure",
  "bank_name": "ConnectPay"
}

Confirm Paid

{
  "success": true,
  "status": "polling",
  "reference": "DP-260330-XA6HSX",
  "message": "Payment verification started. We are checking for your transfer."
}

Check Payment (Polling)

{
  "success": true,
  "status": "confirmed",
  "paid_at": "2026-03-31 10:05:12",
  "invoice_amount": 7.00,
  "total_paid": 7.00,
  "payment_count": 1,
  "payments": [{ "amount": 7.00, "debtor_name": "John Smith", "debtor_iban": "DE89370400440532013000" }],
  "amount_match": true
}

{
  "success": true,
  "status": "partial",
  "invoice_amount": 7.00,
  "total_paid": 3.00,
  "amount_remaining": 4.00,
  "payment_count": 1,
  "payments": [{ "amount": 3.00, "debtor_name": "John Smith" }],
  "message": "We received €3.00 of your €7.00 payment. Remaining balance: €4.00."
}

{
  "success": true,
  "status": "overpaid",
  "paid_at": "2026-03-31 10:05:12",
  "invoice_amount": 5.00,
  "total_paid": 8.00,
  "overpaid_amount": 3.00,
  "refund_fee": 1.00,
  "refund_net": 2.00,
  "message": "Payment received! You overpaid by €3.00. A refund of €2.00 will be processed (€3.00 minus €1.00 processing fee)."
}

{
  "success": true,
  "status": "pending",
  "message": "Payment not yet detected. Checking again...",
  "poll_count": 5,
  "max_polls": 60
}

{
  "success": true,
  "status": "timeout",
  "message": "Payment not detected after maximum attempts. Please contact support."
}

Get Session

{
  "success": true,
  "session_id": 42,
  "merchant_name": "Your Store Name",
  "amount": 49.99,
  "currency": "EUR",
  "status": "confirmed",
  "reference_number": "DP-260330-XA6HSX",
  "invoice_number": "INV-260330-04821",
  "paid_at": "2026-03-30 22:05:12"
}

Payment Status

{
  "success": true,
  "reference_number": "DP-260330-XA6HSX",
  "invoice_number": "INV-260330-04821",
  "amount": 49.99,
  "currency": "EUR",
  "status": "confirmed",
  "confirmed_at": "2026-03-30 22:05:12"
}

List Transactions

{
  "success": true,
  "transactions": [
    {
      "reference_number": "DP-260330-XA6HSX",
      "amount": 49.99,
      "status": "confirmed",
      "confirmed_at": "2026-03-30 22:05:12"
    }
  ],
  "total": 1,
  "limit": 50,
  "offset": 0
}

Webhook: Payment Confirmed

When a payment is confirmed, we send a POST request to your registered callback_url with the payment details.

Webhook Payload

{
  "event": "payment.confirmed",
  "reference_number": "DP-260330-XA6HSX",
  "invoice_number": "INV-260330-04821",
  "merchant_order_id": "ORD-12345",
  "invoice_amount": 7.00,
  "amount_paid": 7.00,
  "amount_remaining": 0,
  "overpaid_amount": 0,
  "refund_amount": 0,
  "refund_fee": 0,
  "currency": "EUR",
  "paid_at": "2026-03-31 10:05:12",
  "session_token": "a1b2c3d4e5f6...",
  "customer_email": "john@example.com",
  "customer_name": "John Smith"
}

Expected Response

Return a 200 status code to acknowledge receipt. If we don't get a 200, we'll flag the notification as undelivered.

PHP Example

Copy<?php
$payload = json_decode(file_get_contents('php://input'), true);

if ($payload['event'] === 'payment.confirmed') {
    $orderId = $payload['merchant_order_id'];  // YOUR order number
    $ref     = $payload['reference_number'];   // Our reference (DP-XXXXXX-XXXXXX)
    $amount  = $payload['amount'];
    $paidAt  = $payload['paid_at'];
    $email   = $payload['customer_email'];

    // Match to your order and mark as paid
    $db->query("UPDATE orders SET status = 'paid', paid_at = '$paidAt' WHERE order_id = '$orderId'");

    // Send confirmation email to customer
    // Trigger fulfillment / shipping

    error_log("Order $orderId paid: €$amount (ref: $ref)");
}

http_response_code(200);
echo json_encode(['received' => true]);

Session & Transaction Statuses

Error Handling

All errors return a JSON object with success: false and an error message:

{
  "success": false,
  "error": "Missing API key"
}

Testing & Environments

Every merchant account starts in staging mode. This lets you integrate and test the full payment flow using ConnectPay's staging environment before going live with real money.

Staging vs Production

Integration Checklist — Staging

Test Accounts for Staging

Use these pre-funded test IBANs to simulate payments in the staging environment. Send EUR from either account to the staging custodial IBAN with the reference number from your checkout session.

Integration Checklist

• Call create_session with your API key and verify you get a session_token
• Call create_invoice and verify you receive the IBAN, beneficiary name, and reference number
• Display the payment details on your checkout page
• Send a small EUR payment (€1-5) from Wise/Revolut to the staging IBAN with the reference number
• Call confirm_paid and then poll check_payment every 7 seconds
• Verify check_payment returns status: "confirmed"
• Verify your webhook endpoint receives the payment.confirmed event with your merchant_order_id
• Call payment_status and verify it returns confirmed

Going Live

• Contact us to switch your account from staging to production
• No code changes needed — same API key, same endpoints, same flow
• Verify create_session response shows "environment": "production"
• Run one real test transaction (€1) to confirm end-to-end
• You're live!

Create Refund

Initiate a full or partial refund for a completed payment. A €1 processing fee is deducted automatically.

{
  "success": true,
  "refund_id": 42,
  "reference_number": "R7A3F2B1",
  "amount": 25.00,
  "processing_fee": 1.00,
  "status": "pending"
}
Copy

Send Refund

Execute a pending refund via SEPA transfer to the customer's IBAN. Calls ConnectPay's outbound payment API.

List Refunds

Settlement Report

Get an aggregated settlement report for a date range — gross volume, refunds, fees, and net settlement amount with daily breakdown.

Dashboard

Recurring Billing — Overview

The recurring billing system sends periodic payment reminders to customers via SMS and/or email. Each cycle generates a new reference number and a link back to the merchant's checkout page. The customer must voluntarily initiate each payment — this is not a direct debit.

Base URL:

https://www.maxafi.com/api/recurring.php

Authentication: Same gateway merchant API key via X-Api-Key header or api_key parameter.

Create Schedule

curl -X POST https://www.maxafi.com/api/recurring.php \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "action": "create_schedule",
    "customer_name": "John Smith",
    "customer_email": "john@example.com",
    "customer_phone": "+4712345678",
    "delivery_method": "both",
    "frequency": "monthly",
    "amount": 99.00,
    "discount_percent": 5,
    "currency": "EUR",
    "order_items": [{"name": "Premium Plan", "qty": 1, "price": 99}],
    "payment_url": "https://merchant-site.com/pay"
  }'
Copy

{
  "success": true,
  "schedule_id": 7,
  "amount": 94.05,
  "original_amount": 99.00,
  "discount_percent": 5,
  "frequency": "monthly",
  "next_billing_date": "2026-04-03"
}
Copy

List Schedules

Update Schedule

Recurring — Configuration

Configure Twilio (SMS) and Gmail SMTP (email) credentials for payment notifications. Stored securely in the database.