curl --request PUT \
  --url https://restapi.sign.plus/v2/envelope/{envelope_id}/attachments/placeholders \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "placeholders": [
    {
      "recipient_id": "<string>",
      "name": "<string>",
      "required": true,
      "multiple": true,
      "id": "<string>",
      "hint": "<string>"
    }
  ]
}
'

import requests

url = "https://restapi.sign.plus/v2/envelope/{envelope_id}/attachments/placeholders"

payload = { "placeholders": [
        {
            "recipient_id": "<string>",
            "name": "<string>",
            "required": True,
            "multiple": True,
            "id": "<string>",
            "hint": "<string>"
        }
    ] }
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'PUT',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    placeholders: [
      {
        recipient_id: '<string>',
        name: '<string>',
        required: true,
        multiple: true,
        id: '<string>',
        hint: '<string>'
      }
    ]
  })
};

fetch('https://restapi.sign.plus/v2/envelope/{envelope_id}/attachments/placeholders', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://restapi.sign.plus/v2/envelope/{envelope_id}/attachments/placeholders",
  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([
    'placeholders' => [
        [
                'recipient_id' => '<string>',
                'name' => '<string>',
                'required' => true,
                'multiple' => true,
                'id' => '<string>',
                'hint' => '<string>'
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

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

curl_close($curl);

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

package main

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

func main() {

	url := "https://restapi.sign.plus/v2/envelope/{envelope_id}/attachments/placeholders"

	payload := strings.NewReader("{\n  \"placeholders\": [\n    {\n      \"recipient_id\": \"<string>\",\n      \"name\": \"<string>\",\n      \"required\": true,\n      \"multiple\": true,\n      \"id\": \"<string>\",\n      \"hint\": \"<string>\"\n    }\n  ]\n}")

	req, _ := http.NewRequest("PUT", 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(string(body))

}

HttpResponse<String> response = Unirest.put("https://restapi.sign.plus/v2/envelope/{envelope_id}/attachments/placeholders")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"placeholders\": [\n    {\n      \"recipient_id\": \"<string>\",\n      \"name\": \"<string>\",\n      \"required\": true,\n      \"multiple\": true,\n      \"id\": \"<string>\",\n      \"hint\": \"<string>\"\n    }\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://restapi.sign.plus/v2/envelope/{envelope_id}/attachments/placeholders")

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

request = Net::HTTP::Put.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"placeholders\": [\n    {\n      \"recipient_id\": \"<string>\",\n      \"name\": \"<string>\",\n      \"required\": true,\n      \"multiple\": true,\n      \"id\": \"<string>\",\n      \"hint\": \"<string>\"\n    }\n  ]\n}"

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

{
  "settings": {
    "visible_to_recipients": true
  },
  "recipients": [
    {
      "recipient_id": "<string>",
      "recipient_name": "<string>",
      "placeholders": [
        {
          "recipient_id": "<string>",
          "id": "<string>",
          "name": "<string>",
          "hint": "<string>",
          "required": true,
          "multiple": true,
          "files": [
            {
              "id": "<string>",
              "name": "<string>",
              "size": 123,
              "mimetype": "<string>"
            }
          ]
        }
      ]
    }
  ]
}