# Recipient Resolution

## What is Recipient Resolution?

**Recipient resolution** is Cheqi's automatic customer identification system. When a customer makes a payment, Cheqi uses their payment information to deliver the receipt directly to their devices—no email address needed.

## Why It Matters

Traditional receipt systems have a problem: **How do you know who to send the receipt to?**

- 📧 **Email receipts** require asking customers for their email at checkout
- 📱 **SMS receipts** require phone numbers and are expensive
- 🧾 **Paper receipts** waste resources and get lost
- 🔗 **QR codes** require customer action


### The Cheqi Solution

Cheqi uses payment information customers already provide to complete their purchase:

✅ **No asking for email** - Seamless checkout experience
✅ **Instant delivery** - Receipt arrives automatically
✅ **Privacy-first** - Customer details stay private
✅ **Always works** - Email fallback for non-users

## How to Use It

### Identify by Card Payment

Use payment information from your terminal:

POS vs Webshop
**For POS Systems:** PAR (Payment Account Reference) is widely available from modern payment terminals and is the recommended method.

**For Webshops:** Email matching is currently the most common approach, though PAR support is growing rapidly as payment providers increasingly expose this data.


```java Java
IdentificationDetails customer = IdentificationDetails.builder()
    .paymentType(PaymentType.CARD_PAYMENT)
    .cardDetails(CardDetails.builder()
        .paymentAccountReference("PAR123456789")
        .cardProvider(CardProvider.VISA)
        .build())
    .customerEmail("customer@example.com")  // Optional fallback
    .build();
```


```csharp C#
var customer = IdentificationDetails.Builder()
    .PaymentType(PaymentType.CARD_PAYMENT)
    .CardDetails(CardDetails.Builder()
        .Par("PAR123456789")
        .CardProvider(CardProvider.VISA)
        .Build())
    .RecipientEmail("customer@example.com")  // Optional fallback
    .Build();
```

### Identify by IBAN

For bank transfer payments:


```java Java
IdentificationDetails customer = IdentificationDetails.builder()
    .paymentType(PaymentType.IBAN_PAYMENT)
    .iban("NL91ABNA0417164300")
    .customerEmail("customer@example.com")  // Optional fallback
    .build();
```


```csharp C#
var customer = IdentificationDetails.Builder()
    .PaymentType(PaymentType.IBAN_PAYMENT)
    .PaymentAccountDetails(PaymentAccountDetails.Builder()
        .Iban("NL91ABNA0417164300")
        .Build())
    .RecipientEmail("customer@example.com")  // Optional fallback
    .Build();
```

## What You Get Back

Cheqi returns encryption keys for matched recipients:


```json
{
  "recipientsFound": true,
  "recipients": [...],
  "webhooks": [...]
}
```

**If customer found:** You receive encryption keys to deliver the receipt
**If customer not found:** Cheqi sends a PDF via email (if provided)

## Simple Integration

The SDK handles everything automatically:


```java Java
// One method does everything: resolve + generate + encrypt + send
ReceiptResult result = sdk.getReceiptService()
    .processCompleteReceipt(
        identificationDetails,  // Customer identification
        receiptRequest          // Receipt data
    );

// Check delivery status
if (result.isSuccess()) {
    System.out.println("✅ Delivered to " + result.getReceiptCount() + " devices");
} else if (result.isDeliveredViaEmail()) {
    System.out.println("📧 Sent to: " + result.getEmailAddress());
} else if (result.isCustomerNotFound()) {
    System.out.println("⚠️ Customer not found - prompt for email");
} else {
    System.out.println("❌ Failed: " + result.getMessage());
}
```


```csharp C#
// One method does everything: resolve + generate + encrypt + send
var result = await sdk.ReceiptService.ProcessCompleteReceiptAsync(
    identificationDetails,  // Customer identification
    receiptRequest          // Receipt data
);

// Check delivery status
if (result.IsSuccess)
{
    Console.WriteLine($"✅ Delivered to {result.ReceiptCount} devices");
}
else if (result.DeliveryMethod == DeliveryMethod.Email)
{
    Console.WriteLine($"📧 Sent to: {result.EmailAddress}");
}
else if (!result.RecipientsFound)
{
    Console.WriteLine("⚠️ Customer not found - prompt for email");
}
else
{
    Console.WriteLine($"❌ Failed: {result.ErrorMessage}");
}
```

## Best Practices

**Always include email fallback** to ensure delivery:


```java
// ✅ Recommended
.customerEmail("customer@example.com")
```

**Handle both scenarios:**

- Customer found → Receipt delivered to their app
- Customer not found → PDF sent via email


## Next Steps

- **[Receipt Flow Overview](/receipts/overview)** - Complete receipt delivery process
- **[SDK Integration](/sdk/java)** - Integrate the Java SDK
- **[.NET SDK](/sdk/dotnet)** - Integrate the .NET SDK
- **[Authentication](/authentication/overview)** - API Keys and OAuth 2.0