Completing DLT registration is only the entry ticket. The obligations that actually determine whether your SMS traffic keeps flowing — template discipline, correct route usage, consent records, time windows — apply every single day after you register. Operators enforce these rules automatically through scrubbing, and violations end in blocked messages, suspended headers or blacklisting under TRAI's TCCCPR regulations. If you have not yet registered as a Principal Entity, start with our DLT registration guide; this article covers what compliance looks like once you are on the platform.
How Scrubbing Works: The Check Every Message Passes
Before any operator (Jio, Airtel, Vi or BSNL) delivers your message, its DLT platform verifies, in real time:
- Entity check: the sender is a registered Principal Entity with a valid Entity ID.
- Header check: the sender ID is registered to that entity, active, and of the right type for the message category.
- Template check: the message content matches a registered template character for character, with variables in the registered positions.
- Preference check: for promotional traffic, the recipient's DND status and category preferences are honoured; for service-explicit traffic, recorded consent exists.
Fail any check and the message is rejected before it reaches a handset — you often still pay for the submission. Most "delivery problems" reported by Indian businesses are actually scrubbing failures.
Content Template Management
Match the template category to the content
- Transactional: OTPs only, effectively reserved for banks and similar critical services.
- Service Implicit: order confirmations, delivery updates, payment alerts, appointment reminders — messages triggered by a customer action.
- Service Explicit: promotional content to customers whose consent is recorded on the DLT platform.
- Promotional: marketing to non-customers or without recorded consent; sent from numeric headers, scrubbed against DND.
Registering marketing content as a service template to dodge DND scrubbing is the most heavily policed violation. Operators run content audits, and mismatched categories lead to template deactivation and header suspension.
Template variable rules
- Variables use the fixed placeholder {#var#} — one per dynamic value.
- Each variable is limited to 30 characters at send time. Long URLs or product names inside one variable cause rejection; split them or shorten links.
- Templates made almost entirely of variables ("Dear {#var#}, {#var#} {#var#}") are rejected or later deactivated, because they allow arbitrary content past scrubbing.
- Keep meaningful fixed text around every variable and identify your brand in the template body.
Common reasons templates get rejected
- Category mismatch — promotional wording (offers, discounts, "buy now") in a service template.
- Missing brand or entity name in the content.
- Excessive or consecutive variables with too little fixed text.
- Duplicate of an already registered template.
- Generic content that could apply to any business, with no identifiable sender context.
The 9 AM – 9 PM Promotional Window
Promotional and service-explicit marketing messages may only be delivered between 9:00 AM and 9:00 PM IST. Operators enforce this at the network level: messages submitted at 9:30 PM are not queued for morning — they are dropped. Schedule campaigns to complete by 8:30 PM to allow for queuing delays, and remember the window applies to delivery time, not submission time. Transactional and service-implicit messages (OTPs, order updates) are exempt and flow 24x7.
Consent and Preference Management
Since the TCCCPR framework, customer preference is not a formality — it is checked on every promotional send.
- DND preferences: subscribers can block all promotional messages or opt out by category (banking, retail, education, health, and so on). Scrubbing applies these automatically.
- Consent registration: to send offers to your own customers on the service-explicit route — including DND numbers — consent must be acquired and registered on the DLT platform through the operator's digital consent process, not just stored in your CRM.
- Consent is scoped: it names your entity and purpose. Consent collected for order updates does not cover marketing, and consent cannot be transferred between entities.
- Revocation must work: customers can withdraw consent at any time; continuing to send after revocation is a direct violation.
Header Misuse, Penalties and Blacklisting
TRAI's enforcement is graded but escalates quickly:
| Violation pattern | Typical consequence |
|---|---|
| Occasional template mismatch | Messages rejected at scrubbing; delivery loss |
| Wrong category usage (marketing on service route) | Template deactivated; header suspended pending review |
| Repeated complaints / UCC reports against a header | Header blacklisted across operators; warning to the entity |
| Persistent violations by the entity | Entity blacklisted — all headers and templates blocked, and telecom resources can be disconnected for up to two years |
Two operational realities are worth noting. First, blacklisting propagates: a header blocked for abuse on one operator platform is shared across the ecosystem. Second, operators periodically deactivate unused headers and templates (inactivity cleanups have used windows in the range of 60–90 days), so audit your DLT portal regularly and re-verify anything you plan to use for seasonal campaigns.
A Monthly DLT Compliance Checklist
- Export active headers and templates from each operator portal; confirm nothing you rely on has been deactivated.
- Reconcile application message content against registered template text — including punctuation and variable count.
- Check variable payloads in logs for values exceeding 30 characters.
- Review rejection (REJECTD) rates per operator; investigate anything above 2–3%.
- Verify promotional scheduling stops by 8:30 PM and never starts before 9 AM.
- Audit consent records for service-explicit campaigns and process any revocations.
- Confirm your telemarketer (gateway) chain is registered and Entity ID and Template IDs are passed correctly in API calls.
Frequently Asked Questions
Why are my messages failing even though my DLT registration is complete?
Registration only creates the entity. Delivery additionally requires an approved header, an approved template that matches your content exactly, both registered on the operator carrying the recipient's number, and the correct Entity and Template IDs passed with each API call. A mismatch in any one of these causes rejection at scrubbing.
Can I send promotional SMS after 9 PM if the customer agreed?
No. The 9 AM – 9 PM window is a regulatory limit enforced by operators for all promotional and service-explicit marketing content, regardless of individual customer consent. Only transactional and service-implicit messages such as OTPs and order updates are delivered round the clock.
What happens if my header gets blacklisted?
All traffic on that header stops across operators, and repeat or serious violations can escalate to entity-level blacklisting, blocking every header you own for up to two years. Recovery requires taking it up with the operator DLT platform, demonstrating corrected practices, and in most cases registering fresh headers — which is far more expensive than staying compliant.