In this article · 10 sections
- What you need to register
- Message categories
- Writing templates that get approved
- URLs and phone numbers in SMS
- Connecting your website
- Protect against SMS abuse
- Is WhatsApp a better option?
- Keep a template register
- Frequently Asked Questions
- Why are my SMS not delivering?
- How long does DLT registration take?
- Can I send promotional SMS to all my customers?
- Do I need DLT for WhatsApp messages?
- Need automated notifications?
Many websites send SMS automatically: OTPs for login, booking confirmations for taxis and clinics, order updates, payment receipts and reminders. In India, commercial SMS is regulated by TRAI to reduce spam. Every business that sends SMS through an SMS provider must register on a DLT (Distributed Ledger Technology) platform. Messages that don't match registered details are blocked by telecom operators.
If your website's SMS suddenly stopped working, DLT mismatches are a very common cause.
What you need to register
| Item | What it is |
|---|---|
| Principal Entity (PE) registration | Your business registered on a telecom operator's DLT portal (e.g., Jio, Airtel, Vi, BSNL portals), with business documents |
| Header / Sender ID | The 6-character name that appears as the sender, like JOBOOW |
| Content templates | Pre-approved message formats with variables for names, OTPs, dates |
| Consent templates (for promotional) | Records of customer consent where required |
| Telemarketer link | Your SMS provider must be linked to your registration |
Registration on one operator's DLT portal is generally shared across operators. Your SMS provider usually guides you through the process.
Message categories
- Transactional / Service-implicit: OTPs, booking confirmations, order updates, account alerts — messages a customer expects because of their action.
- Service-explicit: service messages that need customer consent.
- Promotional: offers and marketing. These are restricted to certain hours and can't be sent to numbers on the Do Not Disturb (DND) registry without valid consent.
Writing templates that get approved
Templates contain fixed text plus variables:
Dear {#var#}, your taxi from {#var#} to {#var#} is confirmed for {#var#}. Driver details will be shared 1 hour before pickup. - JOBOOW- Keep fixed wording clear and specific.
- Use variables only where content changes.
- Include your brand name.
- Make sure the website sends the exact template text with only variables changed — even a missing full stop can cause blocking.
URLs and phone numbers in SMS
TRAI has required links, app download URLs and callback numbers in SMS to be whitelisted with the template or header. If your message includes a link (for example a tracking or payment link), register the domain with your provider first, or messages may be blocked.
Connecting your website
- Choose an SMS provider with good delivery rates and DLT support.
- Complete DLT registration and link the provider.
- Get the provider's API key and template IDs.
- Your developer sends messages through the API, passing the DLT template ID along with the message.
- Log every SMS sent and its delivery status.
- Keep the API key on the server — never in website JavaScript.
Protect against SMS abuse
OTP and "send SMS" forms are often abused by bots, which can drain your SMS balance quickly. Add rate limits per number and per IP, CAPTCHA or Turnstile for public forms, and daily spending caps. See stopping form spam.
Is WhatsApp a better option?
Many customers prefer WhatsApp for confirmations — messages can include rich formatting, buttons and documents. The WhatsApp Business Platform (API) uses its own approved message templates in categories such as utility, authentication and marketing, with per-message pricing set by Meta. Many businesses use WhatsApp for confirmations and SMS as a fallback or for OTPs. See WhatsApp Business App vs API.
Keep a template register
Maintain a simple sheet listing each approved template, its DLT template ID, category, the exact wording and where your website uses it. When your team changes wording on the website, update the register and get the new template approved first. This prevents the most common cause of sudden SMS failures.
Frequently Asked Questions
Why are my SMS not delivering?
Common causes: template text mismatch, wrong template ID, unregistered header, unwhitelisted URL, or insufficient balance.
How long does DLT registration take?
Entity registration and template approvals usually take from a few days to a couple of weeks, depending on the operator and documents.
Can I send promotional SMS to all my customers?
Only within the rules for promotional messages and with proper consent where required. Transactional templates can't be used for promotions.
Do I need DLT for WhatsApp messages?
No. DLT applies to SMS. WhatsApp has its own template approval system through Meta.
Need automated notifications?
Joboo Web integrates SMS and WhatsApp notifications into booking websites. See web development or contact us.