#Multi-Bill Processing Integration Guide

This extends Flow 1 (Bill Fetch → Payment) from the master guide. Only needed when billers return multiple bills in a single fetch (< 1% of billers).

📖 Start here first → Paying Bills Integration Guide

#1. When You Need This Guide

Most developers can skip this guide. You only need multi-bill processing when your Flow 1 fetch response shows:

{
  "billerResponseType": "LIST"
}

This indicates the biller can return multiple bills that require selection before payment.

#1.1 Quick Detection Check

// Add to your existing Flow 1 fetch response handler
if (fetchResponse.data.billerResponseType === "LIST") {
  // Multiple bills detected - implement multi-bill selection UI
  handleMultiBillFlow(fetchResponse);
} else {
  // Single bill - continue with standard Flow 1 implementation
  handleSingleBillFlow(fetchResponse);
}

Example LIST Response Structure:

{
  "data": {
    "refId": "FETCH_REF_123",
    "billerResponseType": "LIST",
    "billerSelectionType": "MULTIPLE",
    "bills": [
      { "billNumber": "BILL_001", "amount": 50000 },
      { "billNumber": "BILL_002", "amount": 75000 }
    ]
  }
}

#2. Common Multi-Bill Scenarios

When billers return multiple outstanding bills:

• Corporate credit cards: Multiple outstanding bills
• B2B invoices: Multiple outstanding invoices requiring payment
• Government eChallans: Bulk payment processing

#3. Selection Rules

The billerSelectionType field determines how many bills users can select:

• "SINGLE" → Choose exactly 1 bill (e.g., one credit card bill)
• "MULTIPLE" → Choose 1+ bills (e.g., select which invoices to pay)
• "ALL" → Must pay all bills together (pay all bills at once)

#4. Implementation Guide

#4.1 Step 1: Build Selection UI

Based on your detection, implement selection interface:

function renderBillSelection(fetchResponse) {
  const { billerSelectionType, bills } = fetchResponse.data;
  
  switch(billerSelectionType) {
    case "SINGLE":
      return renderRadioButtons(bills);  // Only one bill can be paid
    case "MULTIPLE": 
      return renderCheckboxes(bills);    // Any combination of bills can be paid
    case "ALL":
      return renderAllSelected(bills);   // All bills must be paid together
  }
}

#4.2 Step 2: Build Payment Request

Multi-bill payment extends your existing Flow 1 payment with:

{
  "refId": "MULTI_FETCH_REF_123",
  "bills": [
    { "billNumber": "EMP_001_TRAVEL", "amount": 45000 },
    { "billNumber": "EMP_003_TRAINING", "amount": 67000 }
  ],
  "paymentDetails": {
    "amount": 112000,
    "mode": "UPI",
    "paymentRefId": "MULTI_PAY_456",
    "timestamp": "2024-06-04T16:20:00+05:30",
    "accountInfo": "user@ybl"
  },
  "remitter": { "name": "Corporate Account" }
}

Key Differences from Single Bill Payment:

• Add bills array with selected bill details
• Set paymentDetails.amount to sum of selected bills
• Each bill amount must match fetch response exactly

#5. Validation Requirements

Essential Checks:

1. Selection count: Match billerSelectionType requirements (1 for SINGLE, 1+ for MULTIPLE, all for ALL)
2. Amount consistency: paymentDetails.amount must equal sum of selected bill amounts
3. Bill matching: All selected billNumber values must exist in fetch response

#6. Implementation Checklist

1. Add detection logic to your existing Flow 1 fetch handler
2. Build selection UI based on billerSelectionType (radio/checkbox/all-selected)
3. Validate in real-time as users select/deselect bills
4. Use same refId from fetch response in payment request

#7. Reference Links

📖 Related Guides:

• Paying Bills Integration Guide — Master guide with Flow 1 implementation
• Paying for alternative options — Handle payment options within bills
• API Reference — Complete endpoint specifications
• Webhooks Integration — Real-time payment status updates