Under TRAI's regulations, consent is a voluntary permission from the customer to receive commercial communication for a specific purpose, and it can be explicit or inferred. To use it, collect it through a clear process that names your business and the purpose, record when and how it was given, honour opt-outs at once, and wait ninety days before asking again after a revocation.
By Rohit Jadhav. Last reviewed 25 October 2026. This is operational guidance, not legal advice. Data protection rules are also being phased in, so take legal advice on your own consent forms.
"Do we have consent?" sounds like a yes-or-no question. In practice it is a record you either can or cannot show. When a promotional message hits a number that has blocked promotions, consent is the only thing that lets it through, and when a complaint comes in, it is the thing you are asked to produce. This guide explains SMS consent in India: what the regulation says, how to collect it, what proof to keep and where businesses go wrong. It is part of our main guide to DLT registration in India. For help with compliant sending, Nexcomm's bulk SMS service includes compliance support. More guides sit under Compliance & Regulations.
What is consent under TRAI's rules?
The regulation defines consent as any voluntary permission given by the customer to a sender to receive commercial communication related to a specific purpose, product or service. It can be explicit or inferred. Consents sit in a consent register on the DLT system, and a sender that registers headers can act as a consent acquirer through a prescribed process. A consent template, shown to the customer when you ask, must clearly state the purpose of the consent and details of the sender.
What is the difference between explicit and inferred consent?
- Explicit consent is given in a verifiable way, for example when a customer agrees to your request. It lets promotional messages reach the customer irrespective of their registered preferences, as the regulation puts it. For a service message sent to help complete an ongoing transaction, explicit consent is valid for seven days.
- Inferred consent comes from the customer's relationship with you, such as an existing customer receiving service information about what they bought. It does not extend to promotions.
How do you collect consent properly?
- Ask for one purpose at a time. "Updates about your order" and "offers from us" are different permissions.
- Name your business in the request, so the customer knows who is asking.
- Use a plain, unticked box on forms. Do not pre-tick, and do not bundle consent into terms and conditions.
- Use the DLT consent route where your provider supports it. The regulation provides for consent-seeking messages through a designated short code, with the business's name stated clearly in the message.
- Confirm it. A consent confirmation message gives the customer a record too.
- Store it. Keep what the person agreed to and when.
What proof should you keep?
| Record | Why |
|---|---|
| Phone number | Identifies the person |
| Date and time of consent | Shows it was given before you messaged |
| Wording shown | Shows what they agreed to |
| Channel (form, missed call, reply, in person) | Shows how it was collected |
| Purpose and category | Shows which messages it covers |
| Opt-out date, if any | Shows you stopped |
What happens when someone opts out?
Stop sending, and record it. The regulation says a customer who has revoked consent can opt in again at will, but the sender may re-acquire consent only after ninety days from the date of revoking or opting out. Senders must also keep contact information for revocation available for at least thirty days. Promotional messages carry an opt-out in the same message. See DND SMS rules for how preferences and consent interact.
What about WhatsApp opt-in?
WhatsApp's own policy asks businesses to have opt-in permission from the recipient before messaging, and to honour requests to stop. That is a separate requirement from SMS consent. If you use both channels, ask for each one, in words that name the channel.
How does consent affect scrubbing?
When you send a promotional batch, the scrubbing check compares each number with the preference register and the consent register. A number that has blocked promotions passes only if consent is on record. Without it, the message is blocked. See DLT scrubbing, and for the regulation behind it, TCCCPR explained. Headers are covered in SMS sender ID.
A worked example (hypothetical)
A gym chain in Hyderabad wants to send offers to past visitors. This is an invented example. It has 8,000 numbers from enquiry forms, but none of the forms asked about offers. It sends a one-time service message to enquirers about their enquiry only, and adds a clear, unticked option on its forms and website: "Send me offers from the gym by SMS". Over three months, 1,900 people opt in, and the gym stores the date and form version for each. Its first promotional campaign goes to those 1,900. The reply rate is better than on any earlier list, and nobody has to be asked twice.
Common mistakes with consent
- Treating a business card or a form submission as blanket consent. The permission is for a purpose.
- Pre-ticked boxes. They are not voluntary.
- Buying lists. You cannot show consent.
- No record of when or how. You cannot prove it.
- Asking again too soon. Wait ninety days after a revocation.
- Assuming SMS consent covers WhatsApp. Ask for each channel.
- Ignoring opt-outs on one channel. Apply them everywhere you can.
Frequently asked questions
What is consent in SMS marketing in India?
It is a voluntary permission from the customer to receive commercial messages about a specific purpose, product or service. It can be explicit or inferred under the regulation, and it is recorded on the DLT consent register.
Do I need consent to send promotional SMS?
You need either a recipient who has not blocked promotional messages or a recipient who has given you explicit consent. Consent lets a message through even when the person has blocked promotions.
How long do I have to wait to ask again after someone opts out?
Ninety days from the date of revocation or opt-out, under the regulation. The customer can opt in again whenever they choose.
How should I store consent records?
Keep the number, date and time, the exact wording shown, how it was collected, the purpose and any opt-out. Store them securely and limit who can see them.
Does a customer relationship count as consent?
For service information about what they bought, consent can be inferred. For promotions, you need explicit consent or a recipient who has not blocked promotions. Do not stretch the relationship to cover offers.
Sources checked
All checked on 25 October 2026.
- TRAI, consolidated Telecom Commercial Communications Customer Preference Regulations, 2018 (definition of consent; consent register; consent template; ninety-day rule; thirty-day contact information)
- Meta, WhatsApp Business Messaging Policy (last updated 23 September 2026) (opt-in and opt-out)
If you want to review how you collect and store consent, you can reach our team through the contact page.