> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.ntropy.com/documentation/api/personalization/filter-patch-v-3-rules-id-patch/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.ntropy.com/_mcp/server.

# Modify an existing rule

PATCH https://api.ntropy.com/v3/rules/{id}
Content-Type: application/json

Modify an existing rule in the ruleset.

Reference: https://docs.ntropy.com/documentation/api/personalization/filter-patch-v-3-rules-id-patch

## Authentication

- `X-Api-Key` header (required) — API Key authentication via header

## Request

### Path parameters

- `id` (string, required)

### Body (application/json)

This endpoint expects an Action.

- `Action`

## Response

### 200

Successful Response

- `id` (integer, required)

## Errors

### 400 Bad Request Error

Provided index does not exist in ruleset

- `any`

### 422 Unprocessable Entity Error

Validation Error

- `detail` (list of ValidationError, optional)

## Types

### If

- `if` (Expr, required)
- `then` (list of Action, optional)
- `else` (list of Action, optional)

### Setter

- `set` (enum, required)
  - Allowed values: `logo`, `website`, `merchant`, `merchant_id`, `location`, `person`, `transaction_type`
- `to` (Expr, required)

### ValidationError

- `loc` (list of ValidationErrorLocItems, required)
- `msg` (string, required)
- `type` (string, required)

### Expr

### Action

### ValidationErrorLocItems

## Examples

### Example_0

**Request**

```json
{
  "body": {
    "if": {}
  }
}
```

**Response**

```json
{
  "id": 42,
  "add_label": "vip_customer"
}
```

**SDK Code**

```python Example_0
import requests

url = "https://api.ntropy.com/v3/rules/id"

payload = { "body": { "if": {} } }
headers = {
    "X-Api-Key": "<apiKey>",
    "Content-Type": "application/json"
}

response = requests.patch(url, json=payload, headers=headers)

print(response.json())
```

```javascript Example_0
const url = 'https://api.ntropy.com/v3/rules/id';
const options = {
  method: 'PATCH',
  headers: {'X-Api-Key': '<apiKey>', 'Content-Type': 'application/json'},
  body: '{"body":{"if":{}}}'
};

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

```go Example_0
package main

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

func main() {

	url := "https://api.ntropy.com/v3/rules/id"

	payload := strings.NewReader("{\n  \"body\": {\n    \"if\": {}\n  }\n}")

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

	req.Header.Add("X-Api-Key", "<apiKey>")
	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 Example_0
require 'uri'
require 'net/http'

url = URI("https://api.ntropy.com/v3/rules/id")

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

request = Net::HTTP::Patch.new(url)
request["X-Api-Key"] = '<apiKey>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"body\": {\n    \"if\": {}\n  }\n}"

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

```java Example_0
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.patch("https://api.ntropy.com/v3/rules/id")
  .header("X-Api-Key", "<apiKey>")
  .header("Content-Type", "application/json")
  .body("{\n  \"body\": {\n    \"if\": {}\n  }\n}")
  .asString();
```

```php Example_0
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('PATCH', 'https://api.ntropy.com/v3/rules/id', [
  'body' => '{
  "body": {
    "if": {}
  }
}',
  'headers' => [
    'Content-Type' => 'application/json',
    'X-Api-Key' => '<apiKey>',
  ],
]);

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

```csharp Example_0
using RestSharp;

var client = new RestClient("https://api.ntropy.com/v3/rules/id");
var request = new RestRequest(Method.PATCH);
request.AddHeader("X-Api-Key", "<apiKey>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{\n  \"body\": {\n    \"if\": {}\n  }\n}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift Example_0
import Foundation

let headers = [
  "X-Api-Key": "<apiKey>",
  "Content-Type": "application/json"
]
let parameters = ["body": ["if": []]] as [String : Any]

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

let request = NSMutableURLRequest(url: NSURL(string: "https://api.ntropy.com/v3/rules/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()
```

### cURL

**SDK Code**

```python Python SDK
from ntropy_sdk import SDK

sdk = SDK("cd1H...Wmhl")
rule = sdk.rules.patch(
    "42c87677-ff07-4428-a76d-d596cc80c057",
    {"set": "logo", "to": "http://example.com/favicon.ico"},
)
```

```javascript cURL
const url = 'https://api.ntropy.com/v3/rules/:id';
const options = {method: 'PATCH', headers: {'X-Api-Key': '<apiKey>'}};

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

```go cURL
package main

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

func main() {

	url := "https://api.ntropy.com/v3/rules/:id"

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

	req.Header.Add("X-Api-Key", "<apiKey>")

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

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

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

}
```

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

url = URI("https://api.ntropy.com/v3/rules/:id")

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

request = Net::HTTP::Patch.new(url)
request["X-Api-Key"] = '<apiKey>'

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

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

HttpResponse<String> response = Unirest.patch("https://api.ntropy.com/v3/rules/:id")
  .header("X-Api-Key", "<apiKey>")
  .asString();
```

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

$client = new \GuzzleHttp\Client();

$response = $client->request('PATCH', 'https://api.ntropy.com/v3/rules/:id', [
  'headers' => [
    'X-Api-Key' => '<apiKey>',
  ],
]);

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

```csharp cURL
using RestSharp;

var client = new RestClient("https://api.ntropy.com/v3/rules/:id");
var request = new RestRequest(Method.PATCH);
request.AddHeader("X-Api-Key", "<apiKey>");
IRestResponse response = client.Execute(request);
```

```swift cURL
import Foundation

let headers = ["X-Api-Key": "<apiKey>"]

let request = NSMutableURLRequest(url: NSURL(string: "https://api.ntropy.com/v3/rules/:id")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "PATCH"
request.allHTTPHeaderFields = headers

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()
```