curl --request POST \
  --url https://api.syntage.com/entities/{entityId}/shareholders \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "relationType": "shareholders",
  "name": "JUAN MANUEL PEREZ GONZALEZ",
  "shares": 1500.5,
  "rfc": "PEIC211118IS0"
}
'

import requests

url = "https://api.syntage.com/entities/{entityId}/shareholders"

payload = {
    "relationType": "shareholders",
    "name": "JUAN MANUEL PEREZ GONZALEZ",
    "shares": 1500.5,
    "rfc": "PEIC211118IS0"
}
headers = {
    "X-API-Key": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {'X-API-Key': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    relationType: 'shareholders',
    name: 'JUAN MANUEL PEREZ GONZALEZ',
    shares: 1500.5,
    rfc: 'PEIC211118IS0'
  })
};

fetch('https://api.syntage.com/entities/{entityId}/shareholders', 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://api.syntage.com/entities/{entityId}/shareholders",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'relationType' => 'shareholders',
    'name' => 'JUAN MANUEL PEREZ GONZALEZ',
    'shares' => 1500.5,
    'rfc' => 'PEIC211118IS0'
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "X-API-Key: <api-key>"
  ],
]);

$response = curl_exec($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://api.syntage.com/entities/{entityId}/shareholders"

	payload := strings.NewReader("{\n  \"relationType\": \"shareholders\",\n  \"name\": \"JUAN MANUEL PEREZ GONZALEZ\",\n  \"shares\": 1500.5,\n  \"rfc\": \"PEIC211118IS0\"\n}")

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

	req.Header.Add("X-API-Key", "<api-key>")
	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.post("https://api.syntage.com/entities/{entityId}/shareholders")
  .header("X-API-Key", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"relationType\": \"shareholders\",\n  \"name\": \"JUAN MANUEL PEREZ GONZALEZ\",\n  \"shares\": 1500.5,\n  \"rfc\": \"PEIC211118IS0\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.syntage.com/entities/{entityId}/shareholders")

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

request = Net::HTTP::Post.new(url)
request["X-API-Key"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"relationType\": \"shareholders\",\n  \"name\": \"JUAN MANUEL PEREZ GONZALEZ\",\n  \"shares\": 1500.5,\n  \"rfc\": \"PEIC211118IS0\"\n}"

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

{
  "id": "91ab5678-1234-5678-9abc-def012345678",
  "name": "JUAN MANUEL PEREZ GONZALEZ",
  "type": "physical",
  "rfc": "PEIC211118IS0",
  "relations": [
    {
      "id": "82cd9012-3456-7890-abcd-ef1234567890",
      "link": "/entities/91ab5678-1234-5678-9abc-def012345678",
      "shareholder": "<unknown>",
      "relationType": "shareholders",
      "sources": [
        {
          "id": "73de0123-4567-8901-bcde-f23456789012",
          "relation": "<unknown>",
          "shareholder": "<unknown>",
          "sourceName": "manual",
          "sourceId": "64ef1234-5678-9012-cdef-345678901234",
          "shares": 1500.5,
          "createdAt": "2020-01-01T12:15:00.000Z",
          "updatedAt": "2020-01-01T12:15:00.000Z",
          "@id": "/shareholders/91ab5678-1234-5678-9abc-def012345678/relations/82cd9012-3456-7890-abcd-ef1234567890/sources/73de0123-4567-8901-bcde-f23456789012",
          "@type": "ShareholderRelationsSource"
        }
      ],
      "shares": 1500.5,
      "totalShares": 10000,
      "ownership": 0.15,
      "createdAt": "2020-01-01T12:15:00.000Z",
      "updatedAt": "2020-01-01T12:15:00.000Z",
      "@id": "/shareholders/91ab5678-1234-5678-9abc-def012345678/relations/82cd9012-3456-7890-abcd-ef1234567890",
      "@type": "ShareholderRelation"
    }
  ],
  "entity": "/entities/91ab5678-1234-5678-9abc-def012345678",
  "createdAt": "2020-01-01T12:15:00.000Z",
  "updatedAt": "2020-01-01T12:15:00.000Z",
  "@id": "/shareholders/91ab5678-1234-5678-9abc-def012345678",
  "@type": "Shareholder"
}

{
  "message": "<string>"
}

{
  "message": "<string>"
}

{
  "message": "<string>"
}