Kkhay 1.0.4

K Khay .NET SDK 🔷

Official C# and .NET SDK for K Khay — The Non-Custodial Crypto Payment Gateway

Accept cryptocurrency payments across 190+ blockchain networks and 500+ tokens (EVM, Bitcoin, Solana, TON, Tron, and XRPL) with zero custody and automatic direct-to-wallet settlement in ASP.NET Core, Blazor, and .NET applications.

Gateway Dashboard • API Keys • Website

⚡ Highlights

• 🛡️ 100% Non-Custodial: Payments settle directly to your destination blockchain address in seconds. K Khay never holds your private keys or customer funds.
• 🌐 190+ Networks Supported:
  • EVM Networks: Ethereum, BNB Smart Chain, Polygon, Arbitrum, Base, Optimism, Avalanche, and 180+ more.
  • UTXO Chains: Bitcoin (btc), Dogecoin (doge), Litecoin (ltc), Bitcoin Cash (bch).
  • High-Throughput Chains: Solana (sol), TON (ton), Tron (trx), XRP Ledger (xrp).
• 🪙 500+ Tokens: Native coins and tokens (USDT, USDC, BTC, ETH, SOL, TON, BNB, DOGE, XRP, TRX, LTC, and all major tokens).
• 🔗 Branded Hosted Checkouts: Automatic payment links with dynamic QR codes, live blockchain polling, and wallet deep linking.
• 🔔 HMAC-SHA256 Cryptographic Webhooks: Timing-safe verification matching x-kkhay-signature.
• 📦 Dual Target: Supports .NET 8.0 and .NET Standard 2.1 with System.Text.Json serialization.

📦 Installation

Add the official package to your .NET project via the .NET CLI:

dotnet add package Kkhay

Or via Package Manager:

Install-Package Kkhay

🚀 Quick Start

1. Initialize the Client

Generate your API key in the K Khay Gateway Dashboard.

using Kkhay;
using Kkhay.Models;

using var client = new KkhayClient("kkhay_live_your_api_key_here");

In ASP.NET Core (Dependency Injection):

// Program.cs
builder.Services.AddHttpClient<KkhayClient>((sp, httpClient) =>
{
    var apiKey = builder.Configuration["Kkhay:ApiKey"]!;
    return new KkhayClient(httpClient, apiKey);
});

2. Create a Crypto Payment Invoice

Accept stablecoins, native coins, or let the customer choose their preferred token and chain on checkout:

// Example: USDT on BNB Smart Chain (BSC)
var response = await client.CreateInvoiceAsync(new CreateInvoiceRequest
{
    Amount = 49.99m,
    Currency = "USD",
    PayNetwork = "bsc",       // "bsc" | "polygon" | "base" | "arbitrum" | "ethereum" | "solana" | "bitcoin" | "ton"
    PayToken = "USDT",        // "USDT" | "USDC" | "BTC" | "ETH" | "SOL" | "TON"
    OrderId = "ORD-4491",     // Your internal order ID
    Title = "Pro Subscription",
    CustomerEmail = "customer@example.com",
    RedirectUrl = "https://myshop.com/success",
    CancelUrl = "https://myshop.com/cart"
});

Console.WriteLine($"Invoice ID: {response.Invoice.Id}");
Console.WriteLine($"Gateway ID: {response.Invoice.GatewayId}");
Console.WriteLine($"Deposit Address: {response.Invoice.DepositAddress}");
Console.WriteLine($"Hosted Checkout URL: {response.Invoice.HostedUrl}");

// Redirect customer to the checkout page:
// return Results.Redirect(response.Invoice.HostedUrl);

3. Fetch & List Invoices

// Retrieve single invoice with blockchain transaction history
var invoiceDetails = await client.GetInvoiceAsync("01940000-0000-7000-8000-000000000001");

Console.WriteLine($"Status: {invoiceDetails.Invoice.Status}"); // WAITING | PAID | EXPIRED | CANCELED
foreach (var payment in invoiceDetails.Payments)
{
    Console.WriteLine($"Received {payment.AmountReceived} on Tx: {payment.TxHash} (Confirms: {payment.Confirmations})");
}

// List invoices with pagination and filters
var list = await client.ListInvoicesAsync(
    page: 1,
    limit: 20,
    status: GatewayInvoiceStatus.Paid
);

Console.WriteLine($"Total Paid Invoices: {list.TotalCount}");

4. Verify Incoming Webhooks (ASP.NET Core Minimal API)

When a customer pays and the blockchain confirms the transaction, K Khay sends a cryptographically signed POST webhook to your server:

app.MapPost("/api/webhooks/kkhay", async (HttpRequest request) =>
{
    using var reader = new StreamReader(request.Body);
    var rawBody = await reader.ReadToEndAsync();
    var signature = request.Headers["x-kkhay-signature"].ToString();
    var webhookSecret = Environment.GetEnvironmentVariable("KKHAY_WEBHOOK_SECRET")!;

    try
    {
        var evt = Webhook.ParseEvent(rawBody, signature, webhookSecret);

        if (evt.Event == "payment.paid")
        {
            Console.WriteLine($"Payment confirmed for Order: {evt.OrderId}");
            Console.WriteLine($"Tx Hash: {evt.TxHash}");
            Console.WriteLine($"Received: {evt.PayAmount} {evt.PayToken} on {evt.PayNetwork}");
            // Fulfill customer order in database
        }

        return Results.Ok(new { ok = true });
    }
    catch (SignatureVerificationException)
    {
        return Results.Unauthorized();
    }
});

🌐 Supported Networks & Families

📄 License

MIT © K Khay