Bulk SMS and DLT Frequently Asked Questions

What is DLT registration?

Distributed Ledger Technology (DLT) registration is the telecom operator registration process used to identify businesses and messaging entities and manage SMS headers, content templates, and related records. Businesses sending SMS in India should check the current requirements of their telecom operator and register the relevant details before sending messages. See our DLT Registration guide.

Why is DLT registration required?

DLT processes help telecom operators verify business identities and manage headers, templates, and consent-related records. They are intended to improve traceability and help reduce unwanted or fraudulent messaging. The exact steps and required documents can vary by operator.

Who is a Principal Entity (PE)?

A Principal Entity is the business, organisation, or other eligible entity that sends messages to its customers or audience. The entity is responsible for ensuring that its messaging activity, templates, and consent practices meet applicable requirements.

What is a telemarketer in the SMS process?

A telemarketer is a registered service provider involved in transmitting messages for a Principal Entity. The required PE–TM chain and registration details should be configured according to the applicable telecom operator and DLT platform process. Read our PE–TM chain guide.

What is an SMS header or Sender ID?

An SMS header identifies the registered sender of a message. In India, header format and approval depend on the message type and applicable telecom rules. Follow the relevant operator's registration process. Learn more on our SMS Sender ID guide.

What is an SMS content template?

A content template is the message format registered or approved through the applicable DLT process. The message sent should match the approved template and its registered variables as required by the operator. Check the operator's current rules for template creation and approval.

What is a consent template?

A consent template is used in applicable workflows to record or manage a subscriber's consent for messages. Whether it is required depends on the message category and current telecom rules. Businesses should obtain and retain any consent required before sending messages and verify the latest process with their operator.

What are the main SMS message categories?

Message classification depends on its purpose, the recipient relationship, consent, and the applicable telecom framework. Categories may include transactional, service-related, and promotional messaging. Do not select a route based only on the wording of a message; confirm the correct category and current eligibility rules with your telecom operator. See DLT Message Types.

Why can an SMS template be rejected?

Common reasons include an incorrect template ID, a mismatch between the submitted message and approved content, invalid variable placement, or a header or message category that does not match the registration. Compare the submitted text with the approved version and review the platform's rejection details. Our DLT platform error-code guide may help with troubleshooting.

What should I check when using DLT variables?

Use the variable syntax accepted by the relevant DLT platform, and make sure the submitted message matches the approved template structure. Check operator-specific limits and formatting requirements, especially when the message contains dynamic values, punctuation, spaces, or special characters.

What is DND or DNC?

Do Not Disturb (DND) and Do Not Call (DNC) preferences help subscribers manage unsolicited commercial communications. The handling of promotional messages depends on the applicable preferences, consent, message category, and current telecom rules. Businesses should check the current guidance from their operator and TRAI. See our DND/DNC guide.

How can a subscriber manage DND preferences?

Subscribers can use the methods currently provided by their telecom operator and the official telecom preference-registration process. Instructions and category options can change, so verify the latest procedure with the operator or official TRAI resources rather than relying on old SMS keywords.

How many characters can an SMS contain?

For standard SMS encoding, one GSM-7 message segment generally supports up to 160 characters, while concatenated segments generally carry up to 153 characters each. Unicode messages generally support up to 70 characters in one segment and 67 characters per concatenated segment. Some characters may change the encoding, and actual billing can depend on the message content and provider rules.

What is Bulk SMS used for?

Businesses use Bulk SMS for service updates, appointment reminders, order notifications, account alerts, and permitted promotional campaigns. Message type, consent, registration, and delivery depend on the campaign and applicable rules. Explore our Bulk SMS service, service features, and promotional SMS service.

Can OnlineSMS integrate with my application?

Application integration may be available through an SMS API. Review the Developer API information for the supported integration options, credentials, and technical requirements. If you need help selecting an option, contact our team.

What is geofencing?

Geofencing uses a virtual boundary around a geographic area to support location-based experiences or campaign triggers. Implementation depends on the technology, application permissions, device capabilities, and the provider's service. Learn more about our Geo Fencing solution.

How can I get help with DLT or messaging setup?

Review the relevant operator's DLT portal for registration and approval matters. For OnlineSMS account setup or service questions, visit DLT Support or contact OnlineSMS. Keep your error code and relevant non-sensitive details available when requesting support; do not share passwords or OTPs.