Short answer: TRAI’s message categories are not labels, they are prices. The regulations let a terminating operator charge up to ₹0.05 for each promotional SMS and each service SMS, and name no charge at all for transactional SMS. From 17 November 2026, A2P voice calls carry up to ₹0.05 a minute unless they originate from the 140, 1600 or 1601 series.
The four categories, in TRAI’s own words
The definitions are short enough to read directly, and their wording is what a template reviewer holds you to. All four sit in regulation 2 of the Telecom Commercial Communications Customer Preference Regulations, as amended by the Second Amendment gazetted on 12 February 2025.
| Category | What the definition turns on | Explicit consent | Header suffix |
|---|---|---|---|
| Promotional (2(au)) | “the commercial communication containing promotional material or advertisement of a product or service” | Required | -P |
| Transactional (2(bt)) | “a message triggered by a transaction performed by the Subscriber, who is also the Sender’s customer, provided such a message is sent within thirty minutes of the transaction being performed and is directly related to it” | Not required | -T |
| Service (2(bh)) | Sent “either with his consent or using a template registered for the purpose”, to facilitate, complete or confirm a transaction the recipient has consented to, or to give warranty, recall or safety information. TRAI adds that such messages “are not promotional in nature and do not require Explicit Consent” | Not required | -S |
| Government (2(za)) | Sent on the directions of the Central or State Government, a body established under the Constitution, the Authority, or an agency it authorises | Not required | -G |
Mixed content gets no middle category: anything carrying promotional material inside another message type is treated as promotional, with the consent and blocking consequences that follow. TRAI’s sender guidance, last updated 12 October 2026, defines a promotional message as one for which “the sender has not taken any explicit consent”.
Why the category is a price, not just a label
Regulation 35 of the principal regulations sets out what one network may charge another for carrying a commercial message. It names two items and only two:
“Upto Rs. 0.05 (five paisa only) for each promotional SMS;”
“Upto Rs. 0.05 (five paisa only) for each service SMS;”
The word transactional does not appear in regulation 35, and neither does any charge for voice calls. The proviso that follows removes the service SMS charge entirely for government, constitutional-body and Authority-directed messages.
Set that against a published rate. Plivo’s India coverage page, read 13 October 2026, lists domestic outbound SMS at ₹0.20/sms, noting that “Additional carrier charges may apply”. Five paise is 25% of twenty paise — so on the same message, the regulated ceiling on the carrier layer is a quarter of the headline rate for promotional and service traffic, and nil for transactional.
How much of that ceiling reaches your invoice, we cannot tell you. Regulation 35 is a charge the terminating access provider may levy on the originating access provider, not a line item a sender sees, and no aggregator we could read publishes whether it passes the charge on. The chart keeps the two apart, because that is how the evidence sits.
Voice: from 17 November, the category decides whether the call is charged at all
The Third Amendment regulations, gazetted 18 September 2026, insert a new regulation 35A. It lets the terminating access provider charge the originating one up to ₹0.05 “per minute on per minute pulse basis for A2P calls” — calls placed by an application without a human dialling them — capped at the lowest tariff that provider offers the senders it carries.
It then sets out exemptions, and the first is the interesting one: A2P calls from the 140xx, 1600xx and 1601xx series, or another series the Authority designates for commercial communication, “unless notified to the contrary by the Authority”.
TRAI’s accompanying press release describes 140xx as carrying regulated promotional calls and 1600xx and 1601xx as carrying service and transactional calls, and says calls from those series “shall not be flagged as suspected spam for recipients”. Entities must also pre-declare A2P use and their calling line identities to their operator; undeclared A2P calls are treated as unsolicited commercial communication. If you have treated the 1600 series as a compliance chore, it is now a line on the bill too — or rather, the absence of one.
Three dates between now and Christmas
Regulation 1(3) phases commencement from the gazette date of 18 September 2026. We ran the dates rather than eyeballing them.
| Date | What commences | Why it matters here |
|---|---|---|
| 18 October 2026 | General commencement, thirty days after gazette — including amending regulation 17, which adds the cap to regulation 35 | The five-paise SMS ceiling is now also capped at the terminating provider’s lowest offered tariff |
| 17 November 2026 | Amending regulations 4, 6, 8(a) and 18, sixty days after gazette. Amending regulation 18 is the one that inserts regulation 35A | The A2P per-minute voice charge starts, with the 140/1600/1601 exemption |
| 17 December 2026 | The amendments listed in the Annexure, ninety days after gazette | — |
A worked example: 2,50,000 messages at a lender
Take a lender sending, in a month, 40,000 promotional SMS, 1,50,000 transactional SMS (payment confirmations inside the thirty-minute window) and 60,000 service SMS (EMI reminders and statements), at Plivo’s published ₹0.20 domestic rate.
| Category | Volume | At ₹0.20 | If the full regulation 35 ceiling reached the invoice |
|---|---|---|---|
| Promotional | 40,000 | ₹8,000.00 | ₹10,000.00 |
| Transactional | 1,50,000 | ₹30,000.00 | ₹30,000.00 (no charge named) |
| Service | 60,000 | ₹12,000.00 | ₹15,000.00 |
| Total | 2,50,000 | ₹50,000.00 | ₹55,000.00 |
Now add 20,000 EMI reminder calls of 45 seconds each. Regulation 35A charges per minute on a per-minute pulse, so 45 seconds is one chargeable minute: 20,000 minutes. From 17 November that is ₹1,000.00 a month if the calls do not come from a designated series, and nil if they do — ₹12,000.00 a year decided by nothing but the numbering series you originate from. Our own post on per-pulse voice pricing covers how the carriage rate behaves underneath that.
One figure from the same Plivo page dwarfs everything above. The ₹0.20 domestic rate requires DLT registration of the entity, headers, consent templates and message templates; unregistered traffic is “placed on international (ILDO) routes by default” at a published $0.0800/sms. At the European Central Bank reference rate of ₹95.78 to the dollar, dated 12 October 2026, that is ₹7.6624 a message, 38.31× the domestic rate — ₹19,15,600.00 for the same 2,50,000 messages. DLT registration is the largest single price variable on this page.
The layer that never reaches the invoice
Everything above is a cost per message sent. What decides whether a campaign was worth running is the cost per customer reached, and no Indian SMS provider we could read publishes a delivery rate — so we will not invent one. Cost per reached customer is simply the per-message cost divided by your own delivery rate.
| Delivery rate | At ₹0.20 a message | At ₹0.25 a message |
|---|---|---|
| 95% | ₹0.2105 | ₹0.2632 |
| 90% | ₹0.2222 | ₹0.2778 |
| 80% | ₹0.25 | ₹0.3125 |
At 80% delivery a twenty-paise message costs the same per reached customer as a twenty-five-paise message delivered perfectly — which is why delivery belongs on the cost side rather than in an operations report. It is the same argument as our comparison of cost per reached customer across channels.
Where TRAI’s categories and WhatsApp’s do not line up
Send on both channels and you are running two incompatible category systems. TRAI has promotional, transactional, service and government; Meta has marketing, utility, authentication and service, drawn differently. A message TRAI calls transactional is usually Meta’s authentication or utility, and Meta’s test for utility is the stricter of the two.
The prices are not close either. AiSensy’s India card, read 13 October 2026 and stated as effective 1 October 2026, lists marketing at ₹1.09 and utility, authentication and service all at ₹0.145, service charged after 1,000 free messages per number per month. Marketing is about 7.52× utility on that card, and 4.36× the ₹0.25 top of the SMS promotional range here; WhatsApp utility at ₹0.145 sits below the base SMS rate. We sell a competing product, so take the published figures and the dates and check them yourself. Our guide to Meta’s utility and marketing categories covers that side.
So “which category is this?” has to be answered twice, with different tests, for the same business message — and getting it wrong is a price change on both channels. The four layers of a WhatsApp bill behave the same way: the published rate is the smallest part of the question.
What we could not verify
- Whether any aggregator passes the regulation 35 charge through, and at what amount. None publishes it. Plivo’s page says only that additional carrier charges may apply.
- The per-SMS DLT scrubbing charge. The only figure we found sits on a vendor knowledge base with no effective date, so we are not quoting it.
- Principal entity and header registration fees. No operator portal publishes them without a login; that was still the case on 13 October 2026.
- An Indian domestic per-minute voice carriage rate. Plivo’s India voice page would not load on 13 October 2026. Twilio publishes $0.0496/min to Indian mobiles, but that is an international route.
- The current GST schedule entry for telecom services. 18% is what providers’ own cards apply and what we have used above, but the only CBIC page we could read on 13 October 2026 is a pre-rollout press release with no effective date. Treat the tax line as the providers’ figure, not one we verified at source.
Frequently asked questions
Is an OTP transactional or service?
Transactional, if it is triggered by a transaction the customer performed, sent within thirty minutes of it and directly related to it. Those three conditions are the whole test; an OTP outside that window falls under the service definition.
Do I pay the five paise myself?
Not directly. Regulation 35 caps what a terminating operator may charge an originating operator. Whether your aggregator recovers it from you is a commercial term, not a published one — ask for it in writing, by category, before you sign.
Does the category change my DND exposure?
Yes. Promotional traffic is what preference settings block: Schedule II carries a BLOCK PROMO instruction that “shall block only promotional types of Commercial Communications”, while service messages “are not promotional in nature and do not require Explicit Consent”. Mixing an offer into a reminder moves the whole message into the blockable category.
Are 1600-series calls actually cheaper?
From 17 November 2026 they avoid the regulation 35A charge of up to five paise a minute, unless the Authority notifies otherwise. That is one regulated charge, not the whole price: your per-minute carriage rate sits underneath it.
What about government messages?
Regulation 35 carries no service SMS charge for government and constitutional-body messages, and TRAI runs an application process for the exemption. Per TRAI’s page, read 13 October 2026: granted for no more than a year at a time, only after KYC and header registration with an operator, not available to departments that charge customers for the messages, and it waives only the terminating charge — normal delivery charges still apply.
Does the header suffix itself change the price?
The suffix declares the category; the category is what the charge attaches to. Registering a -P header for traffic you consider service does not make it service traffic, and that mismatch is a common reason templates get rejected. If you are choosing categories to manage cost, our pricing page explains how we quote a campaign instead.
How we verified this
Every price, rate and regulation on this page was read from its primary publisher on 13 October 2026 and is dated above. Nothing is carried over from an earlier post without being re-checked, nothing is estimated, and all arithmetic was run rather than eyeballed. Figures we could not verify are named as unverified rather than filled in. We sell messaging and survey campaigns, so where this page names another provider it gives you the published figure and the date we read it, and leaves the comparison to you.
Sources
- TRAI, Telecom Commercial Communications Customer Preference Regulations, 2018 — regulation 2 definitions, regulation 35 charges, Schedule I calling line identity. Read 13 October 2026.
- TRAI, Telecom Commercial Communication Preference (Second Amendment) Regulations, 2025, gazetted 12 February 2025 — Schedule I header suffixes -P, -S, -T, -G; definitions 2(au), 2(bh), 2(bt), 2(za). Read 13 October 2026.
- TRAI, Telecom Commercial Communication Preference (Third Amendment) Regulations, 2026, gazetted 18 September 2026 — regulation 1(3) commencement, amending regulation 17 (regulation 35 cap), amending regulation 18 (new regulation 35A). Read 13 October 2026.
- TRAI, Information Note to the Press No. 119 of 2026 — A2P termination charge, 140xx/1600xx/1601xx series, spam-tagging. Read 13 October 2026.
- TRAI, Advice to Senders, last updated 12 October 2026, and Government Entities, last updated 6 October 2026 — promotional and service definitions, five-paise exemption process. Read 13 October 2026.
- Plivo, India SMS coverage and pricing page — ₹0.20/sms domestic, $0.0800/sms ILDO, DLT registration requirement, carrier charge note. Read 13 October 2026.
- Twilio, India SMS and voice pricing pages — $0.0832/sms, $0.0496/min to mobile. Read 13 October 2026.
- AiSensy, pricing page — India per-message rates effective 1 October 2026. Read 13 October 2026.
- European Central Bank reference rate via the Frankfurter API — 1 USD = ₹95.78, rate dated 12 October 2026.