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# Update Custom Field Definition

PATCH https://app.paymentkit.com/api/{account_id}/custom-field-definitions/{external_id}
Content-Type: application/json

Update a custom field definition.

Only display_name, description, and constraints can be updated.
The field_key, data_type, and entity_type are immutable.

For select fields, you can add new options but cannot remove options that are in use.

Reference: https://docs.paymentkit.com/api-reference/api-reference/custom-field-definitions/update-custom-field-definition

## Authentication

- `Authorization` header (bearer token, required)

## Servers

- `https://app.paymentkit.com` (Production, default)
- `https://staging.paymentkit.com` (Staging)

## Request

### Path parameters

- `external_id` (string, required) — The custom field definition ID (e.g., 'cfd_dev_abc123')
- `account_id` (string, required)

### Body (application/json)

- `display_name` (string, optional, nullable) — Human-readable name for the field
- `description` (string, optional, nullable) — Optional description explaining the field's purpose
- `constraints` (map from string to any, optional, nullable) — Type-specific constraints. For select fields, you can add options but cannot remove options that are in use.
- `is_visible_in_list` (boolean, optional, nullable) — Whether this field appears as a column in list views

## Response

### 200

Successful Response

- `id` (string, required) — Unique identifier for the definition (e.g., 'cfd_dev_abc123')
- `field_key` (string, required) — The key used when setting values on entities
- `entity_type` (enum, required) — The entity type this field applies to
  - Allowed values: `customer`, `subscription`, `product`, `price`, `invoice`, `checkout_session`
- `data_type` (enum, required) — The data type for values
  - Allowed values: `text`, `number`, `boolean`, `select`
- `display_name` (string, required) — Human-readable name for the field
- `is_visible_in_list` (boolean, required) — Whether this field appears as a column in list views
- `created_at` (datetime, required) — When the definition was created
- `updated_at` (datetime, required) — When the definition was last updated
- `description` (string, optional, nullable) — Optional description of the field
- `constraints` (map from string to any, optional, nullable) — Type-specific constraints

## Examples

**Request**

```json
{}
```

**Response**

```json
{
  "id": "cfd_dev_abc123",
  "field_key": "customer_loyalty_level",
  "entity_type": "customer",
  "data_type": "text",
  "display_name": "Loyalty Level",
  "is_visible_in_list": true,
  "created_at": "2024-01-15T09:30:00Z",
  "updated_at": "2024-01-15T09:30:00Z",
  "description": "Indicates the customer's loyalty tier based on purchase history",
  "constraints": {}
}
```

**SDK Code**

```python
from payment_kit import PaymentKit

client = PaymentKit(
    token="YOUR_TOKEN_HERE",
)

client.custom_field_definitions.update_custom_field_definition(
    account_id="account_id",
    external_id="external_id",
)

```

```javascript
const url = 'https://app.paymentkit.com/api/account_id/custom-field-definitions/external_id';
const options = {
  method: 'PATCH',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: '{}'
};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go
package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://app.paymentkit.com/api/account_id/custom-field-definitions/external_id"

	payload := strings.NewReader("{}")

	req, _ := http.NewRequest("PATCH", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```ruby
require 'uri'
require 'net/http'

url = URI("https://app.paymentkit.com/api/account_id/custom-field-definitions/external_id")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Patch.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{}"

response = http.request(request)
puts response.read_body
```

```java
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.patch("https://app.paymentkit.com/api/account_id/custom-field-definitions/external_id")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{}")
  .asString();
```

```php
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('PATCH', 'https://app.paymentkit.com/api/account_id/custom-field-definitions/external_id', [
  'body' => '{}',
  'headers' => [
    'Authorization' => 'Bearer <token>',
    'Content-Type' => 'application/json',
  ],
]);

echo $response->getBody();
```

```csharp
using RestSharp;

var client = new RestClient("https://app.paymentkit.com/api/account_id/custom-field-definitions/external_id");
var request = new RestRequest(Method.PATCH);
request.AddHeader("Authorization", "Bearer <token>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = [
  "Authorization": "Bearer <token>",
  "Content-Type": "application/json"
]
let parameters = [] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://app.paymentkit.com/api/account_id/custom-field-definitions/external_id")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "PATCH"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```