SMS that fits the systems you already run.

<?php
$clientId = getenv('VOMULE_SMS_CLIENT_ID');
$clientSecret = getenv('VOMULE_SMS_CLIENT_SECRET');
$baseUrl = rtrim(getenv('VOMULE_SMS_BASE_URL'), '/');
$path = '/api/v1/send-sms';
$timestamp = time();
$payload = ['msisdn' => '+26650123456', 'message' => 'Hello from PHP', 'request_id' => 'order-1001'];
$rawBody = json_encode($payload, JSON_UNESCAPED_SLASHES);
$bodyHash = hash('sha256', $rawBody);
$signature = hash_hmac('sha256', $timestamp . 'POST' . $path . $bodyHash, $clientSecret);

$ch = curl_init($baseUrl . $path);
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
        'Content-Type: application/json',
        "X-Client-ID: {$clientId}", "X-Timestamp: {$timestamp}",
        "X-Body-Hash: {$bodyHash}", "X-Signature: {$signature}",
    ],
    CURLOPT_POSTFIELDS => $rawBody,
]);
$response = curl_exec($ch);
$status = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
curl_close($ch);

import { createHash, createHmac } from 'node:crypto';

const clientId = process.env.VOMULE_SMS_CLIENT_ID;
const clientSecret = process.env.VOMULE_SMS_CLIENT_SECRET;
const baseUrl = process.env.VOMULE_SMS_BASE_URL.replace(/\/$/, '');
const path = '/api/v1/send-sms';
const timestamp = Math.floor(Date.now() / 1000).toString();
const payload = { msisdn: '+26650123456', message: 'Hello from Node.js', request_id: 'order-1001' };
const rawBody = JSON.stringify(payload);
const bodyHash = createHash('sha256').update(rawBody).digest('hex');
const signature = createHmac('sha256', clientSecret)
  .update(timestamp + 'POST' + path + bodyHash).digest('hex');

const response = await fetch(baseUrl + path, {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json', 'X-Client-ID': clientId,
    'X-Timestamp': timestamp, 'X-Body-Hash': bodyHash, 'X-Signature': signature,
  },
  body: rawBody,
});
console.log(response.status, await response.json());

import hashlib, hmac, json, os, time
import requests

client_id = os.environ['VOMULE_SMS_CLIENT_ID']
client_secret = os.environ['VOMULE_SMS_CLIENT_SECRET']
base_url = os.environ['VOMULE_SMS_BASE_URL'].rstrip('/')
path = '/api/v1/send-sms'
timestamp = str(int(time.time()))
payload = {'msisdn': '+26650123456', 'message': 'Hello from Python', 'request_id': 'order-1001'}
raw_body = json.dumps(payload, separators=(',', ':'), ensure_ascii=False).encode('utf-8')
body_hash = hashlib.sha256(raw_body).hexdigest()
signature_base = (timestamp + 'POST' + path + body_hash).encode('utf-8')
signature = hmac.new(client_secret.encode('utf-8'), signature_base, hashlib.sha256).hexdigest()

response = requests.post(base_url + path, data=raw_body, headers={
    'Content-Type': 'application/json', 'X-Client-ID': client_id,
    'X-Timestamp': timestamp, 'X-Body-Hash': body_hash, 'X-Signature': signature,
})
print(response.status_code, response.json())

<?php
$clientId = getenv('VOMULE_SMS_CLIENT_ID');
$clientSecret = getenv('VOMULE_SMS_CLIENT_SECRET');
$baseUrl = rtrim(getenv('VOMULE_SMS_BASE_URL'), '/');
$path = '/api/v1/send-sms';
$filePath = '/path/to/messages.csv';
$timestamp = time();
$bodyHash = hash_file('sha256', $filePath);
$signature = hash_hmac('sha256', $timestamp . 'POST' . $path . $bodyHash, $clientSecret);

$ch = curl_init($baseUrl . $path);
curl_setopt_array($ch, [
    CURLOPT_POST => true, CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => ["X-Client-ID: {$clientId}", "X-Timestamp: {$timestamp}", "X-Body-Hash: {$bodyHash}", "X-Signature: {$signature}"],
    CURLOPT_POSTFIELDS => ['file' => new CURLFile($filePath)],
]);
$response = curl_exec($ch);
curl_close($ch);

import { createHash, createHmac } from 'node:crypto';
import { readFile } from 'node:fs/promises';

const clientId = process.env.VOMULE_SMS_CLIENT_ID;
const clientSecret = process.env.VOMULE_SMS_CLIENT_SECRET;
const baseUrl = process.env.VOMULE_SMS_BASE_URL.replace(/\/$/, '');
const path = '/api/v1/send-sms';
const timestamp = Math.floor(Date.now() / 1000).toString();
const file = await readFile('/path/to/messages.csv');
const bodyHash = createHash('sha256').update(file).digest('hex');
const signature = createHmac('sha256', clientSecret)
  .update(timestamp + 'POST' + path + bodyHash).digest('hex');
const form = new FormData();
form.append('file', new Blob([file], { type: 'text/csv' }), 'messages.csv');

const response = await fetch(baseUrl + path, {
  method: 'POST',
  headers: { 'X-Client-ID': clientId, 'X-Timestamp': timestamp, 'X-Body-Hash': bodyHash, 'X-Signature': signature },
  body: form,
});
console.log(response.status, await response.json());

import hashlib, hmac, os, time
import requests

client_id = os.environ['VOMULE_SMS_CLIENT_ID']
client_secret = os.environ['VOMULE_SMS_CLIENT_SECRET']
base_url = os.environ['VOMULE_SMS_BASE_URL'].rstrip('/')
path = '/api/v1/send-sms'
file_path = '/path/to/messages.csv'
timestamp = str(int(time.time()))

with open(file_path, 'rb') as source:
    body_hash = hashlib.sha256(source.read()).hexdigest()
signature_base = (timestamp + 'POST' + path + body_hash).encode('utf-8')
signature = hmac.new(client_secret.encode('utf-8'), signature_base, hashlib.sha256).hexdigest()

with open(file_path, 'rb') as source:
    response = requests.post(base_url + path, files={'file': ('messages.csv', source, 'text/csv')}, headers={
        'X-Client-ID': client_id, 'X-Timestamp': timestamp,
        'X-Body-Hash': body_hash, 'X-Signature': signature,
    })
print(response.status_code, response.json())