Nepal Payment Gateway Integration Hub: eSewa, Khalti, ConnectIPS, and Fonepay (2026 Developer Guide)

Nepal's digital payment ecosystem has matured rapidly under the regulatory oversight of Nepal Rastra Bank (NRB). Today, digital transactions represent billions of NPR monthly. For developers building software in Nepal, supporting digital checkout is no longer optional—it is a core requirement. Four major payment providers dominate the Nepali market, each serving distinct use cases: 1. **eSewa:** The pioneer wallet in Nepal with the highest consumer user base. Uses **ePay v2** with HMAC-SHA256 signature verification. 2. **Khalti:** Modern, developer-centric wallet and payment aggregator. Offers **Khalti ePayment v2 API** with clean RESTful JSON endpoints and server-side status lookup. 3. **ConnectIPS (NCHL):** Bank-to-bank direct debit clearing service operated by Nepal Clearing House. Lower merchant fees for large transactions, but requires stricter RSA cryptographic signing. 4. **Fonepay:** Nepal's largest interoperable QR network. Perfect for in-person dynamic QR generation or web checkout using mobile banking apps.

If you are starting a new project in Nepal, choose your gateway based on your current project phase and entity status: - **For College Projects, Portfolios, and Learning:** Start with **Khalti ePayment v2**. Khalti offers immediate sandbox key generation without business registration documents, has comprehensive REST documentation, and returns clear JSON error messages. - **For High-Volume Consumer E-Commerce in Nepal:** Integrate **eSewa** first. Because eSewa has over 7 million registered wallets, it is the payment method Nepali consumers search for on checkout pages. - **For Large Ticket Transactions (Tuition, Vehicles, Real Estate):** Integrate **ConnectIPS**. High percentage transaction fees (2.5%) on a NPR 100,000 transaction cost NPR 2,500 on wallets, whereas ConnectIPS charges a flat micro-fee of around NPR 5 to NPR 10. - **For Multi-Bank Mobile App Checkouts:** Integrate **Fonepay Dynamic QR**. This allows customers to scan using Global IME, Nabil, NIC Asia, or any banking app directly.

Regardless of which gateway you choose, beginner developers routinely commit catastrophic security mistakes that allow malicious actors to spoof transactions. Memorize these golden rules: 1. **Client-side redirects are NOT proof of payment:** When a user returns to your `success_url`, your server MUST NOT mark the order as paid immediately. Users can copy the success URL with forged query parameters. 2. **Server-to-Server Verification is mandatory:** Your backend server must make an independent HTTPS request to the gateway's verification endpoint (e.g. eSewa status API or Khalti `/epayment/lookup/`) using your secret key. 3. **Verify the Amount and Currency:** Compare the amount returned by the gateway with the exact amount recorded in your database before fulfillment. Attackers will attempt to change a NPR 10,000 cart to NPR 10. 4. **Enforce Idempotency:** Payment gateways may send duplicate callbacks due to network retries. Ensure your payment handler checks if the transaction has already been fulfilled to prevent duplicate credits.

// Example of safe, idempotent order fulfillment logic
export async function fulfillOrderSafely(transactionUuid: string, paidAmount: number) {
  const order = await db.orders.findOne({ transactionUuid });
  if (!order) {
    throw new Error("Order not found");
  }

  // Check state machine: Prevent duplicate fulfillment
  if (order.status === "PAID") {
    console.warn(`Duplicate callback ignored for order: ${transactionUuid}`);
    return { success: true, message: "Already fulfilled" };
  }

  // Strict verification: Verify amount match
  if (order.totalAmount !== paidAmount) {
    await db.orders.updateOne({ transactionUuid }, { status: "SUSPICIOUS_AMOUNT_MISMATCH" });
    throw new Error("Fraud alert: Paid amount does not match recorded order amount");
  }

  // Update status atomically
  await db.orders.updateOne(
    { transactionUuid },
    { 
      status: "PAID",
      paidAt: new Date(),
      paymentVerifiedVia: "SERVER_API"
    }
  );

  return { success: true, message: "Order fulfilled securely" };
}

Explore our detailed, step-by-step guides for implementing each provider in production: - [eSewa Payment Integration in Laravel 12](/blog/esewa-payment-integration-laravel-12-complete-guide): Complete controller, routes, CSRF bypass, and HMAC-SHA256 verification. - [Khalti ePayment v2 in Node.js/Express](/blog/khalti-epayment-v2-api-nodejs-express-guide): REST client, `pidx` session handling, and lookup verification. - [Solving the 'Invalid Signature' Error in eSewa](/blog/esewa-invalid-signature-error-causes-and-fixes): 5 root causes, encoding bugs, and exact fixes. - [ConnectIPS Integration in PHP from Scratch](/blog/connectips-integration-php-rsa-key-signing-guide): RSA-SHA256 private/public key generation and settlement. - [Dynamic Fonepay QR in Next.js](/blog/dynamic-fonepay-qr-integration-nextjs-guide): Real-time merchant QR code rendering on the web. - [Stop Spoofed Payment Verification](/blog/stop-spoofed-payment-verification-esewa-khalti-nepal): Advanced anti-spoofing and replay attack prevention.