UPI Auto-Settlement

NoxPay's worker provides real-time settlement for UPI payments by monitoring your bank account's incoming SMS/email alerts via IMAP.

📡 How it Works

When a customer pays via the UPI QR code on the checkout page, they include a specific Remark (usually the Order ID). The NoxPay worker:

1. Connects to your bank email (e.g., Gmail) via IMAP IDLE.
2. Listens for new, unread emails from your bank's notification address.
3. Parses the email body to extract the Amount and UTR (Unique Transaction Reference).
4. Matches the UTR or Order ID against pending payment intents in the database.
5. Marks the transaction as settled and triggers your webhook.

🏦 Supported Banks

NoxPay includes built-in parsers for major Indian banks:

• SBI (State Bank of India): Parses "Ref No" and "Rs." from UPI alerts.
• HDFC Bank: Parses "UPI Ref No" and "INR" from credit notifications.
• Generic Parser: A fallback parser that looks for "UPI" and "INR/Rs" keywords.

🔐 Security (DKIM Verification)

To prevent spoofing attacks (where someone sends a fake email to your worker), NoxPay includes DKIM (DomainKeys Identified Mail) verification.

• The worker verifies the cryptographic signature of the email to ensure it actually came from @sbi.co.in or @hdfcbank.net.
• Emails without valid DKIM signatures from trusted bank domains are automatically discarded.

⚙️ Configuration

You can configure your IMAP settings in the .env file or during the setup.sh process:

• IMAP_SERVER: e.g., imap.gmail.com
• IMAP_PORT: 993
• IMAP_USER: Your email address.
• IMAP_PASSWORD: Your App Password (not your main account password).