Twilio: requires a VISA card. My clients pay with MTN Mobile Money.

Generic SMS solutions: require building everything yourself — no dashboard, no client product, no local support.

Local providers: expensive, poorly documented, support goes quiet on weekends.

POST https://yoolasms.com/api/v1/send.php
Content-Type: application/json

{
    "phone":   "0704487563",
    "message": "Your OTP is 847291. Expires in 5 minutes.",
    "api_key": "YOUR_API_KEY",
    "sender":  "MyApp"
}

{
    "status":       "success",
    "code":         200,
    "recipients":   1,
    "credits_used": 1,
    "balance":      284,
    "message_parts": 1
}

<?php

// Simple helper function — drop this in your helpers file
function yoolaSMS(string $phone, string $message, string $sender = 'YoolaSMS'): array {
    static $apiKey = 'YOUR_API_KEY_HERE';

    $ch = curl_init('https://yoolasms.com/api/v1/send.php');
    curl_setopt_array($ch, [
        CURLOPT_POST           => true,
        CURLOPT_POSTFIELDS     => json_encode([
            'phone'   => $phone,
            'message' => $message,
            'api_key' => $apiKey,
            'sender'  => $sender,
        ]),
        CURLOPT_HTTPHEADER     => ['Content-Type: application/json'],
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_TIMEOUT        => 30,
    ]);
    $result = json_decode(curl_exec($ch), true);
    curl_close($ch);
    return $result ?? ['status' => 'error', 'message' => 'No response'];
}

// OTP verification
$otp = rand(100000, 999999);
$_SESSION['otp'] = $otp;

yoolaSMS(
    $_POST['phone'],
    "Your Yoola SMS verification code is {$otp}. Valid for 5 minutes. Do not share.",
    'MyApp'
);

// Payment confirmation
yoolaSMS(
    $customer_phone,
    "Payment of UGX " . number_format($amount) . " received. Ref: #{$transaction_id}. Thank you!",
    'PayAlert'
);

// Bulk announcement
$phones = implode(',', array_column($members, 'phone'));
$result = yoolaSMS(
    $phones,
    "AGM Notice: Annual General Meeting on Saturday 12th July at 10AM. Venue: Kampala Serena Hotel. RSVP by Thursday.",
    'SACCOAlert'
);
echo "Notified {$result['recipients']} members\n";

import requests
from functools import lru_cache

YOOLA_API_KEY = "YOUR_API_KEY_HERE"
YOOLA_BASE    = "https://yoolasms.com/api/v1"


def send_sms(phone: str | list, message: str, sender: str = "YoolaSMS") -> dict:
    """
    Send SMS via Yoola SMS API.
    phone: single number string or list of numbers
    """
    if isinstance(phone, list):
        phone = ",".join(phone)

    response = requests.post(
        f"{YOOLA_BASE}/send.php",
        json={"phone": phone, "message": message, "api_key": YOOLA_API_KEY, "sender": sender},
        timeout=30,
    )
    return response.json()


@lru_cache(maxsize=1)
def get_balance() -> dict:
    return requests.get(f"{YOOLA_BASE}/balance.php?api_key={YOOLA_API_KEY}").json()


# Django view example
from django.http import JsonResponse

def verify_phone(request):
    if request.method == "POST":
        phone = request.POST.get("phone")
        otp   = generate_otp()

        result = send_sms(
            phone,
            f"Your verification code is {otp}. Expires in 5 minutes.",
            "MyApp"
        )

        if result["status"] == "success":
            request.session["otp"]   = otp
            request.session["phone"] = phone
            return JsonResponse({"success": True})
        else:
            return JsonResponse({"success": False, "error": result["message"]}, status=400)


# Celery task for bulk notifications
from celery import shared_task

@shared_task
def send_bulk_campaign(phones: list, message: str, sender: str):
    """Fire-and-forget bulk SMS task"""
    result = send_sms(phones, message, sender)
    return {
        "sent":    result.get("recipients", 0),
        "credits": result.get("credits_used", 0),
        "balance": result.get("balance", 0),
    }

// lib/sms.js
const YOOLA_API = 'https://yoolasms.com/api/v1/send.php';
const API_KEY   = process.env.YOOLA_API_KEY;

export async function sendSMS(phone, message, sender = 'YoolaSMS') {
  const phones = Array.isArray(phone) ? phone.join(',') : phone;

  const res = await fetch(YOOLA_API, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ phone: phones, message, sender, api_key: API_KEY }),
  });

  if (!res.ok) throw new Error(`HTTP ${res.status}`);
  return res.json();
}

// Next.js API route — pages/api/send-otp.js
import { sendSMS } from '@/lib/sms';

export default async function handler(req, res) {
  if (req.method !== 'POST') return res.status(405).end();

  const { phone } = req.body;
  const otp = Math.floor(100000 + Math.random() * 900000).toString();

  const result = await sendSMS(
    phone,
    `Your verification code is ${otp}. Do not share it. Expires in 5 minutes.`,
    'MyNextApp'
  );

  if (result.status === 'success') {
    // Store OTP in Redis/session for verification
    await redis.setex(`otp:${phone}`, 300, otp);
    return res.json({ success: true });
  }

  return res.status(400).json({ error: result.message });
}

// Express.js example
app.post('/api/notify-all', async (req, res) => {
  const { message } = req.body;
  const users = await db.users.findMany({ select: { phone: true } });

  const result = await sendSMS(
    users.map(u => u.phone),
    message,
    'AppAlert'
  );

  res.json({
    sent:    result.recipients,
    credits: result.credits_used,
    balance: result.balance,
  });
});