curl --request PUT \
  --url https://api.messaging.phonovation.com/people/3/lists/{listName}/items/{itemId} \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "item_field_#1": "new field value"
}
'

import requests

url = "https://api.messaging.phonovation.com/people/3/lists/{listName}/items/{itemId}"

payload = { "item_field_#1": "new field value" }
headers = {
    "Authorization": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

using RestSharp;


var options = new RestClientOptions("https://api.messaging.phonovation.com/people/3/lists/{listName}/items/{itemId}");
var client = new RestClient(options);
var request = new RestRequest("");
request.AddHeader("Authorization", "<api-key>");
request.AddJsonBody("{\n  \"item_field_#1\": \"new field value\"\n}", false);
var response = await client.PutAsync(request);

Console.WriteLine("{0}", response.Content);

HttpResponse<String> response = Unirest.put("https://api.messaging.phonovation.com/people/3/lists/{listName}/items/{itemId}")
  .header("Authorization", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"item_field_#1\": \"new field value\"\n}")
  .asString();

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.messaging.phonovation.com/people/3/lists/{listName}/items/{itemId}",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "PUT",
  CURLOPT_POSTFIELDS => json_encode([
    'item_field_#1' => 'new field value'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: <api-key>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

const options = {
  method: 'PUT',
  headers: {Authorization: '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({'item_field_#1': 'new field value'})
};

fetch('https://api.messaging.phonovation.com/people/3/lists/{listName}/items/{itemId}', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));