JavaScript SDK - Quickei Developer Docs

Drop a single script tag into your website and start accepting payments with Quickei. No backend required — the SDK handles the entire checkout flow in a secure inline modal or popup window.

Installation

Add the Quickei SDK to your page:

<script src="https://quickei.io/sdk/quickei.js"></script>

Load the script before your payment code runs. Place it in the <head> or just before your closing </body> tag.

Quick Start

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>My Store</title>
  <script src="https://quickei.io/sdk/quickei.js"></script>
</head>
<body>
  <button id="pay-btn">Pay 25.00 EUR</button>

  <script>
    const quickei = new Quickei({
      publicKey: 'qi_live_abc123def456'
    });

    document.getElementById('pay-btn').addEventListener('click', () => {
      quickei.pay({
        amount: 25.00,
        currency: 'EUR',
        reference: 'INV-2026-001',
        description: 'Premium subscription',
        customer: {
          email: 'john@example.com',
          name: 'John Doe'
        },
        callbackUrl: 'https://mystore.com/webhook',
        onSuccess: (response) => {
          console.log('Payment successful:', response.trx_id);
          window.location.href = '/thank-you?ref=' + response.reference;
        },
        onCancel: () => {
          console.log('Payment cancelled by user');
        },
        onError: (error) => {
          console.error('Payment error:', error);
        }
      });
    });
  </script>
</body>
</html>

API Reference

Constructor

const quickei = new Quickei({ publicKey });

Parameter	Type	Required	Description
`publicKey`	`string`	Yes	Your public key (`client_id`) from the Merchant Dashboard → API Settings

`quickei.pay(options)`

Opens an inline iframe modal overlay on the current page. The customer completes payment without leaving your site.

quickei.pay({
  amount: 25.00,
  currency: 'EUR',
  reference: 'INV-2026-001',
  description: 'Premium subscription',
  customer: { email: 'john@example.com', name: 'John Doe' },
  callbackUrl: 'https://mystore.com/webhook',
  onSuccess: (response) => { /* ... */ },
  onCancel: () => { /* ... */ },
  onError: (error) => { /* ... */ }
});

Opens payment in a new popup window. Takes the same parameters as pay(). Use this when your site has strict CSP rules or you prefer a separate window.

quickei.popup({
  amount: 50.00,
  currency: 'USD',
  reference: 'ORD-789',
  onSuccess: (response) => {
    console.log('Paid:', response.trx_id);
  }
});

`quickei.close()`

Programmatically close the payment modal or popup. Useful for timeout scenarios or navigation changes.

// Close after 5 minutes of inactivity
setTimeout(() => quickei.close(), 5 * 60 * 1000);

Parameters

All parameters for pay() and popup():

Parameter	Type	Required	Description
`amount`	`number`	Yes	Payment amount (e.g. `25.00`)
`currency`	`string`	Yes	ISO 4217 currency code (e.g. `EUR`, `USD`, `XOF`)
`reference`	`string`	Yes	Your unique order/invoice reference
`description`	`string`	No	Human-readable description shown to the customer
`customer`	`object`	No	Customer details (see below)
`customer.email`	`string`	No	Customer email address
`customer.name`	`string`	No	Customer full name
`callbackUrl`	`string`	No	Server-side webhook URL for payment notifications
`onSuccess`	`function`	No	Called when payment completes successfully
`onCancel`	`function`	No	Called when customer closes the payment modal
`onError`	`function`	No	Called on payment failure or network error

Callback Response

The onSuccess callback receives a response object:

{
  "reference": "INV-2026-001",
  "trx_id": "TRX-A1B2C3D4",
  "amount": 25.00,
  "currency": "EUR",
  "status": "success"
}

Field	Type	Description
`reference`	`string`	Your original order reference
`trx_id`	`string`	Quickei transaction ID
`amount`	`number`	Amount paid
`currency`	`string`	Currency of the payment
`status`	`string`	Payment status (`success`)

Always verify the payment on your server using the callbackUrl webhook or the Check Payment Status endpoint. Client-side callbacks can be spoofed.

Sandbox vs Production

Use key prefixes to switch between environments:

Environment	Key Prefix	Base URL
Sandbox	`qi_test_`	`https://quickei.io/pay/sandbox`
Production	`qi_live_`	`https://quickei.io/pay`

The SDK automatically detects the environment based on your key prefix. No code changes needed — just swap the key.

// Sandbox — test payments, no real charges
const quickei = new Quickei({
  publicKey: 'qi_test_abc123def456'
});

// Production — real payments
const quickei = new Quickei({
  publicKey: 'qi_live_abc123def456'
});

Examples

Complete Checkout Page

A full checkout page with order summary and payment button:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Checkout — My Store</title>
  <script src="https://quickei.io/sdk/quickei.js"></script>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; background: #f5f5f5; }
    .checkout { max-width: 480px; margin: 40px auto; background: #fff; border-radius: 12px; padding: 32px; box-shadow: 0 2px 8px rgba(0,0,0,0.08); }
    .checkout h2 { margin-bottom: 24px; }
    .line-item { display: flex; justify-content: space-between; padding: 12px 0; border-bottom: 1px solid #eee; }
    .total { display: flex; justify-content: space-between; padding: 16px 0; font-weight: 700; font-size: 1.2em; }
    .pay-btn { width: 100%; padding: 16px; background: #095367; color: #fff; border: none; border-radius: 8px; font-size: 16px; font-weight: 600; cursor: pointer; margin-top: 16px; }
    .pay-btn:hover { background: #0a6a82; }
    .pay-btn:disabled { opacity: 0.6; cursor: not-allowed; }
    .status { text-align: center; margin-top: 16px; padding: 12px; border-radius: 8px; display: none; }
    .status.success { display: block; background: #ecfdf5; color: #065f46; }
    .status.error { display: block; background: #fef2f2; color: #991b1b; }
  </style>
</head>
<body>
  <div class="checkout">
    <h2>Order Summary</h2>
    <div class="line-item"><span>Premium Plan (1 year)</span><span>99.00 EUR</span></div>
    <div class="line-item"><span>Setup fee</span><span>10.00 EUR</span></div>
    <div class="total"><span>Total</span><span>109.00 EUR</span></div>

    <button class="pay-btn" id="pay-btn">Pay 109.00 EUR</button>
    <div class="status" id="status"></div>
  </div>

  <script>
    const quickei = new Quickei({
      publicKey: 'qi_live_abc123def456'
    });

    const btn = document.getElementById('pay-btn');
    const status = document.getElementById('status');

    btn.addEventListener('click', () => {
      btn.disabled = true;
      btn.textContent = 'Processing...';

      quickei.pay({
        amount: 109.00,
        currency: 'EUR',
        reference: 'ORD-' + Date.now(),
        description: 'Premium Plan (1 year) + Setup fee',
        customer: {
          email: 'customer@example.com',
          name: 'Jane Doe'
        },
        callbackUrl: 'https://mystore.com/api/quickei-webhook',
        onSuccess: (res) => {
          status.className = 'status success';
          status.textContent = 'Payment successful! Transaction: ' + res.trx_id;
          btn.textContent = 'Paid';
        },
        onCancel: () => {
          btn.disabled = false;
          btn.textContent = 'Pay 109.00 EUR';
        },
        onError: (err) => {
          status.className = 'status error';
          status.textContent = 'Payment failed. Please try again.';
          btn.disabled = false;
          btn.textContent = 'Pay 109.00 EUR';
        }
      });
    });
  </script>
</body>
</html>

Custom Button Styling

You can trigger the payment from any element. Style it however you want:

<style>
  .quickei-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    background: linear-gradient(135deg, #095367, #0891b2);
    color: #fff;
    border: none;
    border-radius: 8px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.15s, box-shadow 0.15s;
  }
  .quickei-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(9, 83, 103, 0.3);
  }
  .quickei-btn svg {
    width: 18px;
    height: 18px;
  }
</style>

<button class="quickei-btn" onclick="handlePayment()">
  <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
    <rect x="1" y="4" width="22" height="16" rx="2" ry="2"/>
    <line x1="1" y1="10" x2="23" y2="10"/>
  </svg>
  Pay with Quickei
</button>

<script>
  const quickei = new Quickei({ publicKey: 'qi_live_abc123def456' });

  function handlePayment() {
    quickei.pay({
      amount: 29.99,
      currency: 'EUR',
      reference: 'ITEM-' + Date.now(),
      description: 'Widget Pro',
      onSuccess: (res) => alert('Thanks! Ref: ' + res.reference)
    });
  }
</script>

Security

Public key only

The SDK uses your public key (client_id). Never include your client_secret in client-side code — it would allow anyone to make API calls on your behalf.

Server-side verification

Always confirm payments server-side using webhooks or the payment status API. Client-side callbacks are for UX only — they can be tampered with.

HTTPS required

The SDK only loads on pages served over HTTPS. Callback URLs must also use HTTPS.

CSP compatible

If you use Content Security Policy headers, allow https://quickei.io in frame-src and script-src directives.

Browser Support

The SDK works in all modern browsers:

Browser	Minimum Version
Chrome	60+
Firefox	55+
Safari	12+
Edge	79+ (Chromium)
Opera	47+
Mobile Chrome	60+
Mobile Safari	12+

Internet Explorer is not supported. The SDK uses modern JavaScript features (Promises, fetch, arrow functions) that require a modern browser.

Integrations

Documentation Index

​Installation

​Quick Start

​API Reference

​Constructor

​quickei.pay(options)

​quickei.popup(options)

​quickei.close()

​Parameters

​Callback Response

​Sandbox vs Production

​Examples

​Complete Checkout Page

​Custom Button Styling

​Security

Public key only

Server-side verification

HTTPS required

CSP compatible

​Browser Support

Installation

Quick Start

API Reference

Constructor

`quickei.pay(options)`

`quickei.popup(options)`

`quickei.close()`

Parameters

Callback Response

Sandbox vs Production

Examples

Complete Checkout Page

Custom Button Styling

Security

Browser Support