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SMS API Documentation

Welcome to the OnlineSMSService API. Our RESTful API allows you to integrate SMS capabilities directly into your applications, websites, or software. Whether you need to send OTPs, transactional alerts, or promotional campaigns, our API delivers with high reliability and speed.

Need an API Key? Request credentials from our team and use the API playground to validate requests before production rollout.

Interactive API Playground

Want to test our API without writing code? Use our interactive playground to send test messages and see real-time responses.

Open API Playground →

Authentication

All API requests must be authenticated using your unique API Key. You can pass the API Key either as a query parameter or in the request body.

Base URL

All API requests should be made to:

https://api.onlinesmsservice.com/send

Send SMS

Send a single text message to one or more recipients.

POST https://api.onlinesmsservice.com/send

Parameters

Parameter Type Required Description
apikey String Yes Your unique API Key
sender String Yes 6-char Sender ID (e.g., ONLSMS)
numbers String Yes Comma-separated mobile numbers (e.g., 919876543210)
message String Yes URL-encoded message content

Success Response

{ "status": "success", "message_id": "MSG_123456789", "cost": 0.10, "parts": 1 }

Code Examples

$apiKey = 'YOUR_API_KEY';
$numbers = '919876543210';
$message = urlencode('Your OTP is 1234');
$sender = 'ONLSMS';

$url = "https://api.onlinesmsservice.com/send?apikey={$apiKey}&numbers={$numbers}&sender={$sender}&message={$message}";

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);
curl_close($ch);

echo $response;

import requests

url = "https://api.onlinesmsservice.com/send"
params = {
    "apikey": "YOUR_API_KEY",
    "numbers": "919876543210",
    "message": "Your OTP is 1234",
    "sender": "ONLSMS"
}

response = requests.post(url, data=params)
print(response.json())

const axios = require('axios');

const params = new URLSearchParams();
params.append('apikey', 'YOUR_API_KEY');
params.append('numbers', '919876543210');
params.append('message', 'Your OTP is 1234');
params.append('sender', 'ONLSMS');

axios.post('https://api.onlinesmsservice.com/send', params)
  .then(response => {
    console.log(response.data);
  })
  .catch(error => {
    console.error(error);
  });

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class SendSMS {
    public static void main(String[] args) {
        try {
            String apiKey = "YOUR_API_KEY";
            String message = "Your OTP is 1234";
            String numbers = "919876543210";
            String sender = "ONLSMS";
            
            String url = "https://api.onlinesmsservice.com/send?apikey=" + apiKey + 
                         "&message=" + message + "&sender=" + sender + "&numbers=" + numbers;
                         
            URL obj = new URL(url);
            HttpURLConnection con = (HttpURLConnection) obj.openConnection();
            con.setRequestMethod("GET");
            
            BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
            String inputLine;
            StringBuffer response = new StringBuffer();
            
            while ((inputLine = in.readLine()) != null) {
                response.append(inputLine);
            }
            in.close();
            
            System.out.println(response.toString());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

curl -X POST https://api.onlinesmsservice.com/send \
     -d "apikey=YOUR_API_KEY" \
     -d "numbers=919876543210" \
     -d "message=Your OTP is 1234" \
     -d "sender=ONLSMS"

Error Codes

Code Description
101 Invalid API Key
102 Insufficient Balance
103 Sender ID not approved
104 Invalid Mobile Number

Webhooks

Use webhooks to receive real-time updates about message delivery statuses directly to your server URL.

Setting Up

1. Go to Dashboard > Settings > Webhooks

2. Enter your callback URL (e.g., https://yourdomain.com/sms-callback)

3. Select the events you want to subscribe to (e.g., Delivery Reports)

Payload Format

We send a POST request to your URL with a JSON body:

{ "event": "message.delivered", "timestamp": "2023-10-25T14:30:00Z", "data": { "message_id": "MSG_123456789", "status": "DELIVERED", "recipient": "919876543210" } }

PHP Example Handler

$json = file_get_contents('php://input');
$data = json_decode($json, true);

if ($data['event'] === 'message.delivered') {
    $messageId = $data['data']['message_id'];
    $status = $data['data']['status'];
    // Update your database
}

http_response_code(200); // Always return 200 OK

Developer FAQ

How quickly can we integrate the SMS API?

Most teams complete first integration within a few hours by testing in sandbox-like conditions and then moving to live credentials.

Can we separate OTP and marketing traffic in one account?

Yes. You can configure sender identities, message templates, and route preferences by workflow type.

Is there guidance for delivery debugging?

Yes. Use message IDs, delivery reports, and webhook logs to isolate template issues, operator filtering, and API payload errors quickly.

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