How to Send OTP Without DLT Registration
A step-by-step guide to sending OTPs in India without any DLT setup. From account creation to your first API call in 5 minutes.
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Step-by-Step Guide
Create Your Account
Sign up at app.startmessaging.com with your email. No company documents or KYC required to get started.
Generate an API Key
Go to the API Keys page in your dashboard and click 'Create API Key'. Copy the key — it is shown only once. The key starts with the sm_live_ prefix.
Top Up Your Wallet
Add funds to your wallet via Razorpay (UPI, cards, netbanking). Each OTP costs Rs 0.25.
Send Your First OTP
Make a POST request to /otp/send with the phone number. We generate and deliver the OTP via SMS in under 2 seconds. See the code examples below.
Verify the OTP
When your user enters the OTP, call POST /v1/otp/verify with the OTP request ID and the code. We handle validation, expiry, and attempt limits.
Works with every language. Just a single POST request.
curl -X POST https://api.startmessaging.com/otp/send \
-H "Content-Type: application/json" \
-H "X-API-Key: sm_live_your_api_key_here" \
-d '{
"phoneNumber": "+919876543210",
"templateId": "YOUR_TEMPLATE_ID",
"variables": {
"otp": "123456",
"appName": "YourApp"
}
}'const response = await fetch("https://api.startmessaging.com/otp/send", {
method: "POST",
headers: {
"Content-Type": "application/json",
"X-API-Key": "sm_live_your_api_key_here",
},
body: JSON.stringify({
phoneNumber: "+919876543210",
templateId: "YOUR_TEMPLATE_ID",
variables: {
otp: "123456",
appName: "YourApp",
},
}),
});
const data = await response.json();
console.log(data);import requests
response = requests.post(
"https://api.startmessaging.com/otp/send",
headers={
"Content-Type": "application/json",
"X-API-Key": "sm_live_your_api_key_here",
},
json={
"phoneNumber": "+919876543210",
"templateId": "YOUR_TEMPLATE_ID",
"variables": {
"otp": "123456",
"appName": "YourApp"
},
},
)
data = response.json()
print(data)$ch = curl_init("https://api.startmessaging.com/otp/send");
curl_setopt_array($ch, [
CURLOPT_RETURNTRANSFER => true,
CURLOPT_POST => true,
CURLOPT_HTTPHEADER => [
"Content-Type: application/json",
"X-API-Key: sm_live_your_api_key_here",
],
CURLOPT_POSTFIELDS => json_encode([
"phoneNumber" => "+919876543210",
"templateId" => "YOUR_TEMPLATE_ID",
"variables" => [
"otp" => "123456",
"appName" => "YourApp"
]
]),
]);
$response = curl_exec($ch);
curl_close($ch);
$data = json_decode($response, true);import java.net.http.*;
import java.net.URI;
HttpClient client = HttpClient.newHttpClient();
String body = """
{
"phoneNumber": "+919876543210",
"templateId": "YOUR_TEMPLATE_ID",
"variables": {
"otp": "123456",
"appName": "YourApp"
}
}
""";
HttpRequest request = HttpRequest.newBuilder()
.uri(URI.create("https://api.startmessaging.com/otp/send"))
.header("Content-Type", "application/json")
.header("X-API-Key", "sm_live_your_api_key_here")
.POST(HttpRequest.BodyPublishers.ofString(body))
.build();
HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
System.out.println(response.body());package main
import (
"bytes"
"encoding/json"
"fmt"
"net/http"
"io"
)
func main() {
payload, _ := json.Marshal(map[string]interface{}{
"phoneNumber": "+919876543210",
"templateId": "YOUR_TEMPLATE_ID",
"variables": map[string]string{
"otp": "123456",
"appName": "YourApp",
},
})
req, _ := http.NewRequest("POST", "https://api.startmessaging.com/otp/send", bytes.NewBuffer(payload))
req.Header.Set("Content-Type", "application/json")
req.Header.Set("X-API-Key", "sm_live_your_api_key_here")
resp, _ := http.DefaultClient.Do(req)
defer resp.Body.Close()
body, _ := io.ReadAll(resp.Body)
fmt.Println(string(body))
}Send OTP Without DLT FAQ
Do I need any documents to sign up?
No. You can sign up with just an email address. No company registration, PAN card, GST certificate, or any other documents are required.
What phone number format should I use?
Use E.164 format: country code + number. For India, that is +91 followed by the 10-digit mobile number. Example: +919876543210.
How many OTPs can I send per second?
We support up to 20 OTPs per second globally per account. This ensures high throughput for production applications during peak times.
How long does an OTP remain valid?
OTPs expire after a configurable time window. The default expiry ensures security while giving users enough time to receive and enter the code.
What happens if SMS delivery fails?
StartMessaging automatically retries with a backup SMS provider. We only retry on service errors (5xx or timeout), not on validation errors like invalid phone numbers.
Related Pages
Ready to Send Your First OTP?
Follow the steps above and go live in under 5 minutes. No DLT registration needed.