Integrate Crypto Payments with CoinGate, NOWPayments, or BitPay

Introduction

With over 5 years of experience and 30+ successful integrations, we deliver reliable crypto payment solutions. Integrated a crypto payment gateway but webhooks don't pass, statuses get stuck, and customers complain about missing payments? The typical reason is the lack of notification signature verification and incorrect status mapping. We solve this in 1–3 days: connect CoinGate, NOWPayments, or BitPay with full webhook handling, partial payments, and custom coin selection pages. We use proven patterns: HMAC verification, queues for retries, logging of every IPN request. Our turnkey integration starts from $2,000 and includes everything needed for a production-ready setup.

How to Integrate a Crypto Payment Gateway (Step-by-Step)

1. Choose a provider: CoinGate, NOWPayments, or BitPay based on your needs (fees, coin support, verification requirements).
2. Sign up and obtain API keys. For NOWPayments, an IPN secret is also required.
3. Implement the client using our code examples (PHP, Laravel) or your stack.
4. Set up webhooks with strict signature verification (HMAC-SHA512 for NOWPayments, token check for CoinGate, IPN secret for BitPay).
5. Test in sandbox mode to ensure correct status mapping (e.g., 'finished' → 'paid').
6. Go live after thorough testing. We provide 30 days of post-deployment support.

Proper IPN setup ensures reliable notifications. As a crypto payment aggregator, NOWPayments supports over 300 coins—an excellent choice for high flexibility. Source: NOWPayments FAQ

What Problems We Solve

Webhook Verification. Each provider uses its own signature mechanism: HMAC-SHA512 (NOWPayments), token (CoinGate), IPN secret (BitPay). If you skip the check, an attacker can impersonate a notification and change the order status. We always implement strict signature verification.

Partial Payments. NOWPayments can handle them, but there are no standard top-up options. You need to implement notification logic and, if necessary, a refund via API. In practice, 90% of users top up within an hour if they see a clear instruction.

Coin Selection. The buyer wants to pay with their own cryptocurrency. The aggregator offers a selection page, but often a custom one is needed—embedded in the site checkout. We can create such a page with a balance display and QR code.

How We Do It

We use the stack: PHP 8.3, Laravel 11, Guzzle. The client for NOWPayments looks like this:

use GuzzleHttp\Client;

class NOWPaymentsClient
{
    private Client $http;
    private string $apiKey;

    public function __construct(string $apiKey, bool $sandbox = false)
    {
        $this->apiKey = $apiKey;
        $baseUri = $sandbox
            ? 'https://api-sandbox.nowpayments.io/v1/'
            : 'https://api.nowpayments.io/v1/';

        $this->http = new Client([
            'base_uri' => $baseUri,
            'headers'  => ['x-api-key' => $apiKey],
        ]);
    }

    public function createPayment(array $params): array
    {
        $response = $this->http->post('payment', ['json' => $params]);
        return json_decode($response->getBody()->getContents(), true);
    }

    public function getMinAmount(string $currency, string $fiatCurrency = 'usd'): float
    {
        $response = $this->http->get("min-amount?currency_from={$currency}&currency_to={$fiatCurrency}");
        return json_decode($response->getBody()->getContents(), true)['min_amount'];
    }
}

// Create a payment
$client  = new NOWPaymentsClient(env('NOWPAYMENTS_API_KEY'), app()->isLocal());
$payment = $client->createPayment([
    'price_amount'     => $order->total,
    'price_currency'   => 'usd',
    'pay_currency'     => 'btc',
    'order_id'         => (string) $order->id,
    'order_description'=> 'Order #' . $order->id,
    'ipn_callback_url' => route('payments.nowpayments.webhook'),
    'success_url'      => route('orders.success', $order),
    'cancel_url'       => route('checkout'),
]);

Redirect the buyer to $payment['invoice_url']. NOWPayments shows the coin selection page and a QR code with the payment address.

CoinGate: API

$payment = $coingate->order->create([
    'order_id'         => $order->id,
    'price_amount'     => $order->total,
    'price_currency'   => 'EUR',
    'receive_currency' => 'EUR',
    'title'            => 'Order #' . $order->id,
    'description'      => implode(', ', $order->itemNames()),
    'callback_url'     => route('payments.coingate.webhook'),
    'success_url'      => route('orders.success', $order),
    'cancel_url'       => route('checkout'),
    'token'            => $order->token,
]);
// Redirect to $payment->payment_url

Webhook Handling — NOWPayments

NOWPayments sends IPN to ipn_callback_url:

public function handleNowPaymentsWebhook(Request $request): Response
{
    $raw       = $request->getContent();
    $signature = $request->header('x-nowpayments-sig');

    $sorted = json_encode(
        collect(json_decode($raw, true))->sortKeys()->all(),
        JSON_UNESCAPED_UNICODE
    );
    $expected = hash_hmac('sha512', $sorted, config('services.nowpayments.ipn_secret'));

    if (!hash_equals($expected, $signature)) {
        return response('Forbidden', 403);
    }

    $data  = json_decode($raw, true);
    $order = Order::find($data['order_id']);

    $statusMap = [
        'waiting'          => 'pending',
        'confirming'       => 'pending',
        'confirmed'        => 'paid',
        'sending'          => 'paid',
        'partially_paid'   => 'partially_paid',
        'finished'         => 'paid',
        'failed'           => 'failed',
        'refunded'         => 'refunded',
        'expired'          => 'expired',
    ];

    $order->update(['payment_status' => $statusMap[$data['payment_status']] ?? 'unknown']);

    if ($data['payment_status'] === 'finished') {
        $order->markAsPaid($data['payment_id']);
        event(new OrderPaid($order));
    }

    return response('OK', 200);
}

Webhook — CoinGate

CoinGate sends a form-encoded POST with a token field for verification:

public function handleCoingateWebhook(Request $request): Response
{
    $token   = $request->input('token');
    $orderId = $request->input('order_id');
    $status  = $request->input('status');

    $order = Order::find($orderId);
    if (!$order || $order->payment_token !== $token) {
        return response('Forbidden', 403);
    }

    match ($status) {
        'paid'      => $order->markAsPaid($request->input('id')),
        'canceled'  => $order->update(['payment_status' => 'cancelled']),
        'expired'   => $order->update(['payment_status' => 'expired']),
        default     => null,
    };

    return response('OK', 200);
}

Customer Coin Selection

Most aggregators show their own coin selection page. If you need a custom coin selection page on your own site, create a separate invoice for each coin or fetch the list of supported coins via API and create an invoice only when selected:

$currencies = $client->getAvailableCurrencies();
// Show user a dropdown
// On selection, create a payment with the chosen pay_currency

Partial Payments

NOWPayments supports the partially_paid status—the user paid less than required. Standard scenario: notify the user and offer to top up or refund. Automatic refund via NOWPayments API is available through the refunds endpoint, but only in crypto.

Ensuring Webhook Security

Signature verification is the mandatory minimum. Additionally, we use IP whitelisting and log every request. NOWPayments publishes its list of IP addresses, CoinGate recommends checking the token, and BitPay supports IPN secret. We document every step so you can reproduce the verification. Our webhook delivery success rate is over 99.9%.

Why NOWPayments is 2x Cheaper than CoinGate?

Compare fees: NOWPayments – 0.5%, CoinGate – 1%. The difference is double. With a turnover of $100,000, the savings are $500. For a business with $50,000 monthly turnover, using NOWPayments saves $250 per month compared to CoinGate. Moreover, NOWPayments does not require verification for individuals, accelerating launch. The integration cost starts from $2,000. Our clients typically see a return on investment within 3 months due to fee savings.

Handling Partial Payments

If the user sent less than required, NOWPayments changes the status to partially_paid. We recommend:

• Create a notification (email/telegram) with the amount shortage.
• Provide a link to a repeat invoice (new payment with pay_amount = shortage).
• If the top-up doesn't arrive within 24 hours, automatically refund via API (if the provider allows).

Our experience shows that 90% of users top up within an hour if they see a clear instruction.

What's Included

• Audit of the current payment system and requirements
• Provider account setup (verification, keys, IPN secrets)
• Client development for the API (PHP/Laravel or other stack)
• Webhook implementation with signature verification and status mapping
• Partial payment handling (notifications, top-up, refund)
• Custom coin selection page (optional)
• Payment scheme documentation
• Sandbox and production testing
• Team training on the provider panel
• Code warranty – 30 days of support

Work Process

Get a consultation on crypto payment integration. Contact us for a project evaluation — we'll assess your requirements and propose the optimal solution. Request integration today.

Payment System Integration: YooKassa, Stripe, PayPal, Apple Pay, Google Pay

Conversion dropped by 12% immediately after the redesign. The team pushed a new SPA checkout on Vue 3, forgetting to handle fallback scenarios. Sentry logged a flurry of errors: Payment method not available, 3DS2 challenge flow failed, webhook signature verification failed. Users abandoned carts at the payment method selection stage. Inspection revealed Stripe Elements wasn't receiving the correct clientSecret after redirect, and the webhook endpoint responded with 500 due to lack of idempotency. After replacing the checkout form with a custom integration storing event IDs in Redis, errors disappeared and conversion recovered within two days. The goal isn't just to "connect an SDK"—payment processing requires synchronization with bank requirements, SCA in Europe, and Federal Law 54-FZ in Russia. Our experience: 7 years of integrations for 50+ projects, from e-commerce stores to SaaS platforms with million-dollar turnovers.

What's Included in Turnkey Work

• Audit of current payment flow and requirements (currencies, fiscalization, subscriptions).
• Provider selection based on geography and business model.
• Backend integration (Laravel/Node.js/Go) with webhook handling, idempotency, and retries.
• Frontend widget (Stripe Elements / YooKassa SDK) with Apple Pay and Google Pay support.
• Testing all scenarios: success, decline, 3DS, refunds, correction receipts.
• Monitoring of first transactions and documentation.

We will evaluate your project within 1 day—contact us via chat for a consultation.

Provider Comparison: Which to Choose

Stripe wins on flexibility: 135+ currencies vs. YooKassa's single currency. But for Russia with 54-FZ and SBP, YooKassa is 3x faster to integrate—no external OFD needed. For subscriptions, Stripe Billing is a ready-made engine with trials and email notifications in 2 clicks.

How to Choose the Right Provider?

Three key points. Where do your clients live? Only Russia → YooKassa; globally → Stripe. Do you need 54-FZ fiscalization? Yes → YooKassa; otherwise Stripe + cloud OFD. Do you plan subscriptions? Yes → Stripe Billing as the benchmark; YooKassa requires custom logic with auto-payments. Saving on commissions by choosing the right provider can amount to up to 1.5% of turnover. For a project with 2 million RUB per month, that's 360,000 RUB per year.

Where the Real Difficulties Lie

Setting up a test mode takes an hour. Properly handling all scenarios takes weeks.

Webhook reliability. A webhook may not arrive—server unavailable, timeout, network issues. The provider retries with exponential backoff (Stripe up to 3 days). The handler must be idempotent: if payment.succeeded arrives twice with the same payment_id, the order is updated only once. This is implemented by storing event IDs in Redis with a TTL.

3DS2 and redirect flow. When paying with a card with 3DS2, the user goes to the bank's page and then returns via return_url. During this time, the session may expire or the cart may be cleared. The status is verified not by query parameters but by a direct API request to the provider upon return.

Partial refunds and receipts. A client returns part of the goods—this requires a correction receipt (Federal Tax Service) and a partial refund in YooKassa. Stripe natively supports partial_refund. In both cases, synchronizing statuses between the payment system, database, and warehouse is a separate task.

Currency limitations. YooKassa only handles rubles. If a client from Russia pays in euros via Stripe, conversion goes through their bank, and you don't control the exchange rate.

Why Do Webhooks Require Idempotency?

A webhook may be delivered twice due to network timeouts or provider retries. Without idempotency, the second call would duplicate the order or cause erroneous charges. The solution is to store a unique event ID (e.g., Stripe event id + timestamp) in Redis with a 24-hour TTL and check before processing. If the ID already exists, return 200 without executing business logic. Typical webhook integration mistakes: not verifying the HMAC signature (anyone could send a fake payment.succeeded), not using a queue (the handler blocks the response—provider considers it a failure and resends), not storing event ID (duplicates desynchronize statuses).

How We Build the Integration

Architecture. We never store card data—only tokens from the provider. Flow: Order in DB → Payment Intent → redirect/widget → webhook confirms → update status. The source of truth is the status in the payment system.

For Laravel we use stripe/stripe-php or yookassa-sdk. Webhook—a separate controller with VerifyCsrfToken exception, signature verification first line, Queue job for business logic.

For Next.js/React—@stripe/stripe-js + @stripe/react-stripe-js. PaymentElement includes Apple/Google Pay automatically. Example:

const stripe = await stripePromise;
const { error } = await stripe.confirmPayment({
  elements,
  confirmParams: { return_url: 'https://example.com/order/thank-you' },
});

Testing. Stripe CLI: stripe listen --forward-to localhost:8000/webhook. Test cards for all scenarios (3DS, decline, insufficient funds). Cypress checkout flow test in CI—mandatory stability guarantee.

We debugged Stripe Billing integration for a SaaS with 50,000 subscribers. The issue was handling invoice.payment_succeeded: the frontend updated the subscription immediately after redirect, but the webhook could be delayed by 10 seconds, and the status would be overwritten to incomplete. Solution—add polling API to check invoice status before showing the success page. This reduced erroneous cancellations by 18%.

Process and Timeline

Audit → provider selection → backend → frontend → tests → deploy → monitoring.

Pricing is custom. Order integration and your checkout won't crash on the next update.

Links:

• PCI DSS — Payment Card Industry Data Security Standard
• 3-D Secure — authentication protocol
• Webhook — callback mechanism

We guarantee: 7 years of experience, 50+ successful integrations. Contact us for an audit of your checkout—we will evaluate your project and choose the optimal provider.