How to Send OTP with CodeIgniter 4 (2026)

CodeIgniter 4 is widely used by Indian agencies. This tutorial wires StartMessaging via CURLRequest.

Setup

composer create-project codeigniter4/appstarter otp-ci
cd otp-ci

Config

# .env
SM_API_KEY=sm_live_xxxxxxxxxxxxxxxx
SM_BASE_URL=https://api.startmessaging.com

StartMessaging Library

<?php
// app/Libraries/StartMessaging.php
namespace App\Libraries;

use CodeIgniter\HTTP\CURLRequest;

class StartMessaging
{
    private CURLRequest $client;

    public function __construct()
    {
        $this->client = service('curlrequest', [
            'baseURI' => env('SM_BASE_URL'),
            'headers' => [
                'X-API-Key'    => env('SM_API_KEY'),
                'Content-Type' => 'application/json',
            ],
            'timeout' => 10,
        ]);
    }

    public function sendOtp(string $phone): array
    {
        $r = $this->client->post('/otp/send', [
            'json' => ['phoneNumber' => $phone, 'idempotencyKey' => bin2hex(random_bytes(16))],
        ]);
        return json_decode((string) $r->getBody(), true)['data'];
    }

    public function verifyOtp(string $rid, string $code): bool
    {
        $r = $this->client->post('/otp/verify', [
            'json' => ['requestId' => $rid, 'otpCode' => $code],
            'http_errors' => false,
        ]);
        return $r->getStatusCode() === 200;
    }
}

Auth Controller

<?php
// app/Controllers/Auth.php
namespace App\Controllers;

use App\Libraries\StartMessaging;

class Auth extends BaseController
{
    public function sendOtp()
    {
        $sm = new StartMessaging();
        $data = $sm->sendOtp($this->request->getJsonVar('phoneNumber'));
        session()->set('otp_req', $data['requestId']);
        return $this->response->setJSON(['expiresAt' => $data['expiresAt']]);
    }

    public function verifyOtp()
    {
        $sm = new StartMessaging();
        $rid = session()->get('otp_req');
        if (!$rid) return $this->response->setStatusCode(400)->setJSON(['error' => 'no otp']);
        $ok = $sm->verifyOtp($rid, $this->request->getJsonVar('otpCode'));
        return $this->response->setStatusCode($ok ? 200 : 401)->setJSON(['verified' => $ok]);
    }
}

FAQ

Looking for the same thing in Laravel? Our Laravel guide.