curl --request POST \
  --url https://api.railmail.app/api/v1/subscribers/{email}/consents \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "topicKey": "APIT-1",
  "source": "preference-center",
  "ipAddress": "203.0.113.10",
  "userAgent": "Mozilla/5.0",
  "sourceUrl": "https://shop.example.com/prefs",
  "consentText": "I agree to receive the newsletter",
  "formVersion": "v3"
}
'

import requests

url = "https://api.railmail.app/api/v1/subscribers/{email}/consents"

payload = {
    "topicKey": "APIT-1",
    "source": "preference-center",
    "ipAddress": "203.0.113.10",
    "userAgent": "Mozilla/5.0",
    "sourceUrl": "https://shop.example.com/prefs",
    "consentText": "I agree to receive the newsletter",
    "formVersion": "v3"
}
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({
    topicKey: 'APIT-1',
    source: 'preference-center',
    ipAddress: '203.0.113.10',
    userAgent: 'Mozilla/5.0',
    sourceUrl: 'https://shop.example.com/prefs',
    consentText: 'I agree to receive the newsletter',
    formVersion: 'v3'
  })
};

fetch('https://api.railmail.app/api/v1/subscribers/{email}/consents', 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.railmail.app/api/v1/subscribers/{email}/consents",
  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([
    'topicKey' => 'APIT-1',
    'source' => 'preference-center',
    'ipAddress' => '203.0.113.10',
    'userAgent' => 'Mozilla/5.0',
    'sourceUrl' => 'https://shop.example.com/prefs',
    'consentText' => 'I agree to receive the newsletter',
    'formVersion' => 'v3'
  ]),
  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.railmail.app/api/v1/subscribers/{email}/consents"

	payload := strings.NewReader("{\n  \"topicKey\": \"APIT-1\",\n  \"source\": \"preference-center\",\n  \"ipAddress\": \"203.0.113.10\",\n  \"userAgent\": \"Mozilla/5.0\",\n  \"sourceUrl\": \"https://shop.example.com/prefs\",\n  \"consentText\": \"I agree to receive the newsletter\",\n  \"formVersion\": \"v3\"\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.railmail.app/api/v1/subscribers/{email}/consents")
  .header("X-API-Key", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"topicKey\": \"APIT-1\",\n  \"source\": \"preference-center\",\n  \"ipAddress\": \"203.0.113.10\",\n  \"userAgent\": \"Mozilla/5.0\",\n  \"sourceUrl\": \"https://shop.example.com/prefs\",\n  \"consentText\": \"I agree to receive the newsletter\",\n  \"formVersion\": \"v3\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.railmail.app/api/v1/subscribers/{email}/consents")

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  \"topicKey\": \"APIT-1\",\n  \"source\": \"preference-center\",\n  \"ipAddress\": \"203.0.113.10\",\n  \"userAgent\": \"Mozilla/5.0\",\n  \"sourceUrl\": \"https://shop.example.com/prefs\",\n  \"consentText\": \"I agree to receive the newsletter\",\n  \"formVersion\": \"v3\"\n}"

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