OTP delivery that your users actually receive — on the first try.
Priority routes to Indian operators, DLT-compliant templates, automatic fallbacks, and a simple API that your team can ship in an afternoon. Built for login, signup, payment, and high-value transaction flows.
otp-dispatch.sh
Priority route$ curl -X POST https://api.smslocal.in/v1/otp/send \ -H 'Authorization: Bearer sk_live_xxx' \ -H 'Content-Type: application/json' \ -d '{ "template_id": "DLT_TEMPLATE_ID", "to": "+919876543210", "variables": { "otp": "482913" } }'Response · POST /v1/otp/send
webhook · /delivery
Awaiting carrier…
Latency
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Powering authentication across Indian fintech, e-commerce, logistics and SaaS
Authentication infrastructure your security team can defend.
OTPs are on the critical path of your signup and checkout funnels. A 2-second delay costs you conversions; a failed delivery costs you the user entirely. SMSLocal is engineered for the boring, unglamorous reliability those flows need.
Priority operator routes
OTP traffic is routed on transactional-priority paths with the major Indian carriers — separate from promotional queues.
Sub-second delivery target
Typical delivery completes in under a second across major operators under normal network conditions.
DLT-compliant templates
Pre-approved OTP template library plus an in-dashboard template workflow aligned to TRAI DLT norms.
Automatic retry & fallback
Configurable retry logic and secondary routes kick in automatically on operator timeouts or failures.
Tamper-resistant delivery
Signed webhooks, TLS everywhere, and per-key scoping keep OTP pipelines isolated from marketing traffic.
Smart route selection
Dynamic route scoring picks the fastest, most reliable operator path per number range in real time.
From API call to delivered code in four steps.
- Step 1
Call the OTP API
POST to /v1/otp/send with a phone number, DLT template ID, and variables. Returns a message ID you can use for tracking.
- Step 2
Route scoring picks a path
Our router picks the best priority operator route for that number range based on live success and latency data.
- Step 3
Delivery to the handset
The SMS is delivered directly to the user's device over a transactional-priority path that never competes with promotional traffic for operator bandwidth.
- Step 4
Webhook confirms delivery
A signed delivery webhook hits your endpoint with the final status — delivered, failed, or expired.
Integrate in minutes, not sprints.
A single REST endpoint, an API key, and a DLT template. That is all you need to ship OTPs to production. Idiomatic snippets in the languages your stack already runs.
import fetch from "node-fetch"
const res = await fetch("https://api.smslocal.in/v1/otp/send", {
method: "POST",
headers: {
"Authorization": "Bearer " + process.env.SMSLOCAL_API_KEY,
"Content-Type": "application/json",
},
body: JSON.stringify({
to: "+919876543210",
template_id: "OTP_LOGIN_V1",
sender_id: "SMSLCL",
variables: { otp: "482915", minutes: 10 },
}),
})
const data = await res.json()
console.log(data.message_id, data.status)Built-in verification
- Optional /verify endpoint validates the OTP server-side so you never store it.
- Configurable code length, alphabet, and expiry window per template.
- Per-user rate limits and cooldowns prevent brute-force and enumeration.
Production signals
- Signed webhooks for every status transition — sent, delivered, failed, expired.
- Per-number and per-template delivery dashboards in real time.
- Exportable delivery reports for audit, reconciliation, and BI pipelines.
Safe by default
- Scoped API keys per environment — dev, staging, and production are isolated.
- IP allowlists and per-key rate limits available on all paid plans.
- Automatic PII redaction in logs; full request payloads available on enterprise plans.
Everything an auth team needs — nothing it does not.
Template versioning
Clone, A/B test, and roll out OTP templates with full version history — every old version stays linked to the messages it sent so audit and recon never drift.
Fraud velocity controls
Per-IP, per-user, and per-number rate limits with configurable cooldowns and exponential backoff.
Indian + international
Optimised for Indian carriers out of the box with global delivery available on request for cross-border flows.
Configurable expiry
Set code validity per template, from 30 seconds for high-risk flows up to 15 minutes for slower UX flows.
WhatsApp fallback
Automatically fall back from SMS to WhatsApp OTP on delivery failure (enterprise plans).
Transparent billing
Per-SMS pricing with no markups on failed deliveries and consolidated monthly invoicing with GST.
Why teams move OTP traffic onto SMSLocal.
| Feature | SMSLocal OTP API | General SMS gateways | In-app-only OTP |
|---|---|---|---|
| Priority operator routes | Yes — dedicated transactional lanes | Mixed with promotional traffic | Not applicable |
| DLT template workflow | Built into dashboard | Partial — often manual | Not applicable |
| Typical delivery latency | Sub-second on major carriers | Variable, often seconds to minutes | Dependent on push reliability |
| Retry & fallback logic | Automatic, configurable | Usually manual | Not applicable |
| Signed delivery webhooks | Yes, HMAC-signed | Varies by vendor | N/A |
| Indian support coverage | India-based, product-trained team | Often offshore | N/A |
Every OTP is a trust decision. Make it instant, make it arrive.
Fastest-route selection, automatic retries, and WhatsApp fallback on enterprise — built around the one metric that matters: sub-5-second delivery.
Where OTP SMS is the critical path.
Fintech & banking
Login, high-value transactions, UPI confirmations, and KYC verification flows.
E-commerce & D2C
Signup, guest checkout verification, COD confirmation, and account recovery.
SaaS & mobile apps
Passwordless login, 2FA enrollment, device pairing, and sensitive setting changes.
Healthcare & govt.
Appointment confirmations, teleconsultation access codes, and citizen service flows.
Sub-1s
typical OTP delivery on major Indian carriers
99.99%
platform uptime, measured monthly
24/7
priority routing for DND and non-DND numbers
Minutes
from API key to first OTP in production
OTP SMS, answered.
How is OTP delivery different from regular bulk SMS?
OTP traffic is routed on transactional-priority paths, uses pre-approved DLT templates, includes built-in retry and fallback logic, and is isolated from promotional queues so it does not compete with marketing blasts for operator bandwidth.
Do I need to register DLT templates myself?
You need a registered DLT header and template, yes — but our dashboard walks you through it and we maintain a library of common OTP templates you can clone and customise.
What happens if the user's phone is off or out of coverage?
Operator-side stores hold the SMS for up to 24 hours and re-attempt delivery as soon as the handset is reachable. Our routing layer surfaces a 'pending' status in your dashboard and fires a webhook once the final state is known — delivered, expired, or failed — so your retry logic can decide when to send a second OTP without the user receiving two at once.
Can SMSLocal generate and verify the OTP for me?
Yes. You can either generate the code yourself and pass it in, or use our managed /send + /verify endpoints where we generate the code, handle expiry, and verify server-side so you never store the OTP.
Is OTP SMS secure for high-value transactions?
OTP SMS is industry standard for banking, payments, and government flows in India, and we add signed webhooks, per-key scoping, IP allowlists, and rate limiting on top. For very high-risk flows we recommend combining OTP with additional signals like device fingerprinting.
What about fallback to WhatsApp?
On our enterprise plan, failed SMS OTP attempts can automatically fall back to WhatsApp OTP for WhatsApp-active users, maximising delivery success across networks.
OTPs are rarely a product of one.
Most teams combine OTP with transactional SMS, WhatsApp verification, or industry-specific authentication flows.
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See it in your industry
Give your users OTPs that just work.
Get an API key in minutes, ship OTPs in an afternoon, and stop losing signups to bad delivery.