# Modify Customs fields for a guest

The **`xp-customs-fields`** endpoint allows partners to modify a list of customs fields (customer or stay). 

### Request

<mark style="color:orange;">**POST**</mark>

```url
https://interface.experience-hotel.com/api/xp-customs-fields?email=test@test.com
```

**URL Parameter**: `email` (the email address of the customer)

#### Body&#x20;

Example to modify a Customer Custom field&#x20;

```json
{
    "customer_custom_fields": [
        {
            "name": "Loyalty level",
            "values": [
                "Silver"
            ]
        }
    ]
}
```

Example to modify a Stay Custom field, you will need to specify the Stay reference, which is the unique reference of the reservation in the PMS.&#x20;

```json
{
     "stay_custom_fields": [
        {
            "stay_reference": "123456",
            "data": [
                {
                    "name": "ota_src",
                    "value": "Booking.com"
                }
            ]
        }
    ]
}
```

You can combine a modification of Customer and Stay fields in the same request, for example:&#x20;

```json
{
    "customer_custom_fields": [
        {
            "name": "Loyalty level",
            "values": [
                "Silver"
            ]
        }
    ],
    "stay_custom_fields": [
        {
            "stay_reference": "123456",
            "data": [
                {
                    "name": "ota_src",
                    "value": "Booking.com"
                }
            ]
        }
    ]
}
```

### Possible return&#x20;

<mark style="color:green;">`200 OK`</mark>

```json
{
    "successes": {
        "customer_custom_fields": [
            "Loyalty level"
        ]
    },
    "errors": {
        "customer_custom_fields": []
    }
}
```

<mark style="color:orange;">`404 Not Found`</mark>

```json
"customer not found"
```

&#x20;No Customer found with this email in the CRM.&#x20;


---

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