What is an OTP SMS API?

An OTP (One-Time Password) SMS API lets your application send a numeric verification code to a user's phone number programmatically. The user reads the code, enters it back into your app, and you confirm the phone number belongs to them. It is the most widely-used verification method in India because every smartphone receives SMS without requiring an internet connection or a specific app installed.

A production OTP API needs more than just sending a message: you need DLT compliance, a high-deliverability route across all four major Indian operators, retry logic when the first SMS fails, a way to handle international roaming customers, and webhooks so your backend knows whether the OTP actually reached the user.

Why Pick SpringEdge for OTP SMS in India

Sub-3-Second Delivery

Average OTP delivery time across Jio, Airtel, Vi, and BSNL is under 3 seconds. Direct operator routes — no SMS aggregator hops.

DLT-Approved Templates

Submit your OTP template once; we get it approved on TRAI's DLT platform across all four operators. No back-and-forth.

4 or 6-Digit Codes

Choose code length per request. Codes are cryptographically generated server-side; you can also pass your own.

Retry & Fallback

Automatic re-send on first-attempt failure. Voice OTP fallback available for users on Do Not Disturb (DND) lists.

INR Pricing

Pay-as-you-go in INR. From ₹0.12 per OTP at high volume. No setup fee, no monthly minimum, no contract.

Free Test Credits

Verify your full integration end-to-end with free test credits before paying. Sandbox uses production endpoints.

Send Your First OTP in 3 Lines of Code

Replace YOUR_API_KEY with the key from your dashboard and <SMS_SERVICE_URL> with your SMS service URL (shared after sign-up), then send a test OTP to any verified phone number.

cURL

curl -X POST "<SMS_SERVICE_URL>/api/web/send/" \ --data-urlencode "apikey=YOUR_API_KEY" \ --data-urlencode "sender=SPEDGE" \ --data-urlencode "to=919876543210" \ --data-urlencode "message=Your OTP is 482917 - SpringEdge" \ --data-urlencode "format=json"

PHP

$otp = str_pad(random_int(0, 999999), 6, '0', STR_PAD_LEFT); $ch = curl_init('<SMS_SERVICE_URL>/api/web/send/'); curl_setopt_array($ch, [ CURLOPT_POST => true, CURLOPT_POSTFIELDS => http_build_query([ 'apikey' => 'YOUR_API_KEY', 'sender' => 'SPEDGE', 'to' => '919876543210', 'message' => "Your OTP is {$otp} - SpringEdge", 'format' => 'json', ]), CURLOPT_RETURNTRANSFER => true, ]); $response = curl_exec($ch); curl_close($ch);

Node.js (official springedge package)

const springedge = require('springedge'); const otp = String(Math.floor(100000 + Math.random() * 900000)); springedge.messages.send({ apikey: 'YOUR_API_KEY', sender: 'SPEDGE', to: ['919876543210'], message: `Your OTP is ${otp} - SpringEdge`, format: 'json' }, 5000, (err, response) => { if (err) return console.error(err); console.log(response); });

For deeper integration examples (delivery reports, message status, credit balance), see the SpringEdge API documentation or import the Postman collection.

DLT-Approved OTP Template

Every transactional SMS sent to an Indian number must use a TRAI DLT-approved template — including OTPs. SpringEdge handles the approval submission for you. Typical OTP template formats:

Your OTP for {#var#} is {#var#}. Valid for 5 minutes. Do not share. - SpringEdge Use {#var#} to verify your mobile number on {#var#}. Do not share with anyone. - YourBrand

Where {#var#} is a placeholder you fill at send time. Approval typically completes in 24-48 hours. We help you draft templates that get approved on the first attempt — see our DLT template approval guide.

OTP SMS Use Cases

Banking & Fintech

2FA for login, transaction approval, beneficiary addition, password reset, NEFT/UPI confirmations.

E-Commerce

Account signup verification, COD order confirmation, return pickup OTP, refund confirmation.

Travel & Hospitality

Booking PIN, check-in OTP, ride-share rider verification, room access codes, e-ticket access.

Healthcare

Patient ID verification, prescription pickup OTP, telemedicine appointment access, lab report access.

Account Login

Passwordless login (OTP-only), 2FA on existing password login, suspicious-device verification.

Government & KYC

Aadhaar-linked verification flows, document submission confirmation, e-KYC mobile verification.

OTP SMS Pricing

Transparent INR pay-as-you-go pricing. No setup fees, no monthly minimums.

Volume / month Price per OTP (approx.) Best for
Up to 25,000₹0.18Early-stage startups, sandbox & pilot
25,001 — 1,00,000₹0.15Growth-stage SaaS, fintech
1,00,001 — 10,00,000₹0.13E-commerce, marketplace
Above 10,00,000₹0.12 or customBanks, large fintech, enterprise

See full SMS pricing for current rates. Volume discounts apply automatically based on monthly usage. Contact our sales team for enterprise contracts above 10 lakh OTPs/month.

Frequently Asked Questions

SpringEdge OTP SMS pricing starts at ₹0.18 per OTP for low volumes (under 25,000/month) and drops to ₹0.12 at high volumes (above 10 lakh/month). All prices are in INR with no setup fees, no monthly minimums, and no contract. See /pricing for current rates.

Typically 24-48 hours after submission. We pre-review your template draft against TRAI DLT guidelines so it gets approved on the first attempt. See our DLT template approval guide for the exact format.

Average delivery time is under 3 seconds across Jio, Airtel, Vi, and BSNL on direct operator routes. P95 delivery is under 8 seconds. Delivery is occasionally delayed by operator congestion or DND list issues, which is why we recommend using webhooks to confirm delivery before showing "Resend OTP" in your UI.

Yes. The platform retries automatically on transient operator failures. For permanent failures (invalid number, blacklisted recipient), the failure is reported via webhook so your application can prompt the user to correct the number or fall back to a Voice OTP.

5-10 minutes is the typical balance between security and user experience. Many fintech apps use 60-180 seconds for transaction OTPs. We recommend storing the expiry server-side, not in the SMS body, so you can change policy without re-approving the DLT template.

6-digit is the security-recommended default (one million combinations vs ten thousand). 4-digit is faster to type but more brute-forceable. Combine 4-digit codes with strict rate limits (e.g. 3 attempts, 30-minute lockout) to keep them safe. SpringEdge supports both lengths in the same API.

Yes. SpringEdge supports OTP SMS to 85+ countries. International OTPs do not require DLT compliance (DLT is India-only) but are billed at country-specific rates. See global messaging for the supported country list.

5-15 minutes for a basic implementation: signup, copy the API key, paste a code sample, send your first OTP. Production hardening (rate limiting, retry-after timing, fallback to Voice OTP, webhook handling) typically adds another half-day to a day of work.

Default rate limit is 100 requests/second per API key, with burst allowance to 200/second. Higher limits are available on request for enterprise accounts. We do not throttle based on monthly volume, only per-second rate.

Yes. After signup you receive free test credits that work against the same production endpoints — no separate sandbox URL or sandbox-only API key. This means your test code works unchanged when you move to production.

Start sending OTPs in 5 minutes

Free signup with test credits. No credit card required. DLT template assistance included.

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