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DLT-ready · India-first

SMS that arrives, on the same platform as WhatsApp and email

Send OTPs, order alerts and promotional SMS through one API, with TRAI DLT registration walked through for you and one customer record shared with your WhatsApp and email programmes.

Start free →See the DLT guide
✓ DLT template matchedWhatsApp → SMS fallback

Why SMS still matters

The channel of last resort, done properly

No internet, no app, no problem

SMS reaches every phone with a signal — the channel of last resort for the message that absolutely has to arrive.

DLT rejects silently

A sender, header or template that isn’t registered gets dropped with no explanation, unless something checks it first.

A second stack loses opt-outs

A separate vendor and contact list means a WhatsApp opt-out never reaches your SMS list, and nobody can see the full history.

DLT compliance

Every send checked against your registered templates

TRAI’s DLT regime requires every sender, header and template to be registered before an operator will carry the message — and a mismatch is usually rejected with no explanation. sendlz treats that as part of onboarding: we take you through registration, hold your approved templates on the platform, and refuse to send content that doesn’t match one.

  • Entity, sender ID and templates — we walk you through registration
  • Content matched against your approved templates before it leaves the platform
  • Separate headers for transactional and promotional, so a complaint never touches OTP delivery
See the DLT guide →
POST /v1/messageschannel=sms
  • Sender IDSNDLZ
  • Templatelogin_otp_v2
  • DLT matchApproved
  • Segments1

Blocked before send if it doesn’t match a template

Omnichannel fallback

If WhatsApp doesn’t deliver, SMS does — automatically

List the channels in order on one send: sendlz tries the first and moves to the next only if it fails or goes undelivered past your window, so a customer normally gets one message, not two. Consent, suppression and the full conversation stay on the same customer record throughout.

  • One API call, channels listed in order
  • SMS sends only if WhatsApp fails or goes undelivered past your window
  • One customer record and one consent ledger across every channel
Explore omnichannel messaging →

order_shipped

  1. 1WhatsApp utility template
  2. 2No delivery in 2 min: SMS sent
  3. 3Receipt copy by email
  4. 4Reply or opt-out stops all

Use cases

Where SMS earns its place in the stack

OTP and authentication

The fallback that catches the share of numbers not on WhatsApp, at the authentication rate.

Order and delivery alerts

Time-critical updates that must land even when a WhatsApp message doesn’t.

Promotional campaigns

DND-scrubbed and sent inside the permitted window, under a header that never touches OTP traffic.

Payment confirmations

A receipt the customer sees even on a patchy connection, reconciled on the same ledger as the rest.

For developers

One API for every channel

Sending an SMS is the same call as WhatsApp or email — only the channel changes.

  • POST /v1/messages
  • GET /v1/templates
  • POST /v1/webhooks
Read the API docs →
Send an OTP by SMS
curl -X POST https://api.sendlz.com/v1/messages \
  -H "Authorization: Bearer $SENDLZ_KEY" \
  -H "Idempotency-Key: otp_88231" \
  -d channel=sms \
  -d to=+919812345678 \
  -d template=login_otp_v2 \
  -d vars[code]=482913

{ "id": "msg_01JQ...", "status": "queued",
  "channel": "sms", "segments": 1 }

Channel comparison

When SMS is the right channel

The three channels overlap less than they appear to.

SMSWhatsAppEmail
Reaches a phone with no internetYesNoNo
Recipient needs an app or accountNoneWhatsAppA mailbox
Setup in IndiaTRAI DLT registrationMeta template reviewSPF, DKIM and DMARC
Rich media, buttons, catalogText and a linkYesYes
Two-way conversationLimitedYesSlow
Best jobOTP fallback, urgent alertsUtility updates, commerce, serviceReceipts, long-form, newsletters

Getting started

From signup to first SMS

  1. 1

    Register on DLT

    Entity, sender ID and templates on an operator portal. We give you the checklist and the exact fields.

  2. 2

    Connect to sendlz

    Add your headers and approved templates to the console, and bind the platform as your delivery partner.

  3. 3

    Test in the sandbox

    Send to test numbers and inspect the delivery events before a real customer sees anything.

  4. 4

    Go live

    Call the API or launch a campaign; replies and receipts land in the same timeline as your other channels.

Why sendlz

SMS without a second stack

One platform, one record

Contact, consent and suppression shared across WhatsApp, SMS and email — not three separate lists.

DLT handled for you

Registration walked through step by step, and every send checked against your approved templates first.

Automatic fallback

SMS catches the customers WhatsApp couldn’t reach, on the same send, without a second integration.

Built for developers

The same REST API, signed webhooks and idempotency keys as WhatsApp and email — only the channel changes.

SMS API questions, answered

Do I need DLT registration to send SMS in India?

Yes — entity, sender ID and every message template must be registered on a telecom operator’s DLT portal before an operator will deliver your SMS. We walk you through it, and WhatsApp needs none of it.

Can I send promotional SMS as well as OTPs?

Yes, but under separate headers and templates. Promotional messages are subject to DND scrubbing and the permitted sending window, and keeping them apart from transactional traffic protects OTP delivery.

What happens if an SMS does not match a registered template?

It is rejected by the operator, and many providers surface that only as a failed delivery. sendlz checks your content against your registered templates first and returns the mismatch in the API response.

Can SMS act as a fallback for WhatsApp?

Yes. Set a fallback window on the send; if WhatsApp does not report delivery in that time, the SMS goes out and the WhatsApp attempt is closed, so the customer receives one message.

Do SMS and WhatsApp share an opt-out?

Yes. Suppression and consent are held once per contact, so an opt-out on any channel is respected on all of them.

Ready to add SMS to your platform?

Create a free account and send your first SMS today. No credit card required.

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