KasGate: Universal Kaspa Payment Gateway

Accept Kaspa cryptocurrency payments on any website with a single API call.

Live Demo

kasgate-production.up.railway.app/dashboard

Create a free account to explore the full dashboard.

Demo Video

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What Is KasGate?

KasGate is the Stripe of Kaspa. Register as a merchant, get an API key, and start accepting KAS payments in minutes.

• Create a payment session with one POST request
• KasGate generates a unique Kaspa address per payment
• Your webhook fires when the blockchain confirms the transaction
• Track everything from the dashboard in real time

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Screenshots

Dashboard	Sessions	Integration

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Features

• Simple API: Create payments with a single POST request
• Real-time updates: WebSocket-powered payment notifications
• Non-custodial: Merchants control their own keys via xPub HD wallet
• Webhook system: HMAC-signed server-to-server notifications
• Drop-in widget: Embed a payment form in 3 lines of HTML
• Kasware support: One-click payments with browser wallet
• Multi-network: Single env var switches testnet to mainnet
• 71 tests: Unit and integration tests across all critical paths

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Tech Stack

Layer	Technology
Runtime	Bun
Backend	TypeScript, Express
Frontend	Next.js 14, Tailwind CSS, shadcn/ui
Database	SQLite via better-sqlite3
Blockchain	Kaspa RPC (testnet-10 / mainnet)
Testing	Vitest
Deployment	Railway

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Testing the Full Flow

No real KAS needed. KasGate runs on Kaspa testnet-10 so you can test the entire payment flow for free.

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Part 1: Setup (one time)

1. Get a Kaspa wallet and export your xPub key

You need a Kaspa wallet that lets you export your xPub (extended public key). This is how KasGate generates a unique deposit address per payment without storing your private key.

Kaspa-NG (desktop/web):

• Create a wallet and switch to testnet-10 in settings
• Go to Wallet > Settings > Export xPub
• Copy the key starting with xpub...

KasWare (browser extension):

• Install the extension and create a wallet
• Switch network to testnet-10
• Go to Account Details > Export xPub

2. Get testnet KAS from the faucet

Go to faucet.kaspanet.io and paste your testnet address to receive free test KAS.

Note: testnet addresses start with kaspatest: not kaspa:. Make sure your wallet is on testnet-10 before copying the address.

3. Register as a merchant

Go to kasgate-production.up.railway.app/dashboard/register:

• Enter your name and email
• Paste your xPub key
• Submit. Your account is created and your API key is shown on the dashboard

Keep your API key safe. You can regenerate it from the dashboard if needed.

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Part 2: Test a payment from the terminal

The fastest way to verify the full flow without building a frontend.

1. Create a payment session

curl -X POST https://kasgate-production.up.railway.app/api/v1/sessions \
  -H "Content-Type: application/json" \
  -H "X-API-Key: YOUR_API_KEY" \
  -d '{"amount": "1", "orderId": "test_001"}'

Response:

{
  "id": "sess_abc123",
  "address": "kaspatest:qr...",
  "amount": "1",
  "status": "pending",
  "expiresAt": "2024-01-01T12:10:00Z"
}

2. Send KAS to the generated address

Open Kaspa-NG or KasWare, send exactly 1 KAS (testnet) to the address from the response. The address is unique to this payment session.

3. Poll for confirmation

curl https://kasgate-production.up.railway.app/api/v1/sessions/sess_abc123 \
  -H "X-API-Key: YOUR_API_KEY"

Run this every 10-15 seconds. Status moves from pending to confirmed once the transaction is picked up on-chain. Testnet-10 confirms in under a minute.

4. Check the dashboard

Open the dashboard. The session appears under Sessions with its status updating in real time.

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Part 3: Integrate into your app

REST API

Add payment creation to your backend:

// Create a payment session when a user checks out
const response = await fetch('https://kasgate-production.up.railway.app/api/v1/sessions', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'X-API-Key': process.env.KASGATE_API_KEY
  },
  body: JSON.stringify({
    amount: '10.5',         // Amount in KAS
    orderId: 'order_123'    // Your internal order ID
  })
});

const session = await response.json();
// Show session.address to your user. They send payment here.
// Store session.id to poll status or match with webhook.

Listen for payment confirmation via webhook:

app.post('/webhook/kaspa', express.raw({ type: 'application/json' }), (req, res) => {
  const signature = req.headers['x-kasgate-signature'];
  const expected = crypto
    .createHmac('sha256', process.env.KASGATE_WEBHOOK_SECRET)
    .update(req.body)
    .digest('hex');

  if (!crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(expected))) {
    return res.status(401).send('Invalid signature');
  }

  const { event, sessionId, txId, amount } = JSON.parse(req.body);

  if (event === 'payment.confirmed') {
    fulfillOrder(sessionId);
  }

  res.status(200).send('OK');
});

Register your webhook URL from the dashboard under Settings > Webhook.

Drop-in widget (no backend needed)

Add a payment button to any webpage in 3 lines:

<script src="https://kasgate-production.up.railway.app/widget/kasgate.js"></script>
<kas-gate
  api-key="your_api_key"
  amount="10.5"
  order-id="order_123"
  theme="dark"
></kas-gate>

The widget shows the address, QR code, and confirms when payment arrives.

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Checking webhook delivery

Every webhook attempt is logged. Go to Dashboard > Webhook Logs to see which events fired, the payload sent, your server's response, and any failed deliveries. KasGate retries failed webhooks automatically.

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API Reference

All endpoints require X-API-Key header.

Method	Endpoint	Description
POST	/api/v1/sessions	Create a payment session
GET	/api/v1/sessions/:id	Get payment status
POST	/api/v1/sessions/:id/cancel	Cancel a pending payment
GET	/api/v1/merchants/me	Get merchant profile
GET	/api/v1/merchants/me/sessions	List all payments
GET	/api/v1/merchants/me/stats	Payment statistics
GET	/api/v1/merchants/me/analytics	Revenue analytics
GET	/api/v1/merchants/me/webhook-logs	Webhook delivery logs

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Running Locally

git clone https://github.com/dmustapha/kasgate.git
cd kasgate
bun install
cp .env.example .env
bun run dev

Visit http://localhost:3000/dashboard

# Run tests
bun test

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Architecture

┌─────────────────┐     POST /api/v1/sessions      ┌──────────────────┐
│   Your Website  │ ──────────────────────────────> │  KasGate Server  │
│  (any frontend) │ <── { address, sessionId } ──── │  (Express + Bun) │
└─────────────────┘                                 └────────┬─────────┘
                                                             │
                          ┌──────────────────────────────────┤
                          │                                  │
                   ┌──────▼──────┐                   ┌───────▼───────┐
                   │  Kaspa RPC  │                   │   SQLite DB   │
                   │  (Testnet / │                   │  (Payments,   │
                   │   Mainnet)  │                   │   Merchants)  │
                   └──────┬──────┘                   └───────────────┘
                          │
              Payment confirmed on-chain
                          │
                   ┌──────▼──────┐
                   │   Webhook   │
                   │  (HMAC sig) │ ──> Your server notified
                   └─────────────┘

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Contact

• X: @Kas_Gate
• Email: damilolamustaphaa@gmail.com

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License

MIT