SMS

Your agent can send a customer an SMS while it is talking to them (a booking link mid-call, an address they asked for) and after the call ends (a thank-you with your booking link, or a “sorry we missed you”). See Actions and After the call. SMS goes through your own provider account. You connect your SMS provider, it sends under your own sender ID, and it bills you directly. Nothing for SMS is taken from your wallet here.

SMS reaches Indian mobile numbers only. Every business SMS in India has to follow the DLT rules below, and those apply to Indian numbers. For customers elsewhere, use WhatsApp.

What DLT asks of you first

India’s telecom rules (TRAI’s DLT) mean an operator only delivers a business SMS that matches what you registered in advance. You register once on any one DLT portal (Jio, Airtel, Vi, BSNL…), and it works on every network. If your business already sends OTPs or order updates, you probably have all of this.

You need	What it is	Where it comes from
Entity (PE) ID	Your business’s registration on DLT, usually 19 digits	Your DLT portal, once your business is approved
Sender ID (header)	The six letters the message shows as coming from, like `ACMEIN`	Registered on your DLT portal
Templates	The exact words of each message, with `{#var#}` wherever the text changes	Registered and approved on your DLT portal; each gets a DLT template ID
Your provider in your PE–TM chain	Telling DLT which provider sends for you	Your DLT portal — add your provider’s telemarketer ID

Do the PE–TM chain step, or every message is dropped. Since 2024 operators reject a message unless your DLT registration names the provider that delivered it. Your provider’s support team will give you their telemarketer ID if it is not below.

Providers you can connect

Provider	You’ll need	Templates also need	Telemarketer ID
MSG91	Auth key	MSG91’s own template ID (from its dashboard)	`1302157225275643280`
Exotel	Account SID, API key, API token, region (`in` or `sg`)	—	ask Exotel
Gupshup Enterprise SMS	User ID, password	—	ask Gupshup
Infobip	Your API base URL (like `xxxxx.api.infobip.com`), API key	—	`110200001152`
Vonage	API key, API secret	—	ask Vonage
Fast2SMS	API key	Fast2SMS’s own message ID (from its DLT manager)	ask Fast2SMS

MSG91 and Fast2SMS send by their own copy of each template, so you add the template on their dashboard too and paste their ID here. The others send your template’s text along with your DLT IDs. Using a different provider? Tell us which one. We add a provider once we can test its DLT sending API against its own documentation.

Connect

Open Settings → SMS provider

Only owners and admins can change it.

Choose your provider and paste its keys

Then enter your DLT sender ID (header) and your DLT entity (PE) ID. Keys are sealed as soon as they arrive and never shown again. To change one field later, leave the secret blank and the saved one is kept.

Add your templates

Under DLT templates, add each template you want the agent to use:

Name — your own, like booking_link. The agent sees it, so make it say what the message is for.
Text — copied from your DLT portal exactly, with {#var#} where it varies.
DLT template ID — the number your DLT portal gave it.
Category — Transactional, or Service (implicit or explicit). Promotional templates can’t be sent by an agent.
Agent may send this during a call or chat — tick it for the templates you want the agent to be able to use mid-call. New templates start unticked. The after the call message doesn’t need the tick.
MSG91 template ID / Fast2SMS message ID — only with those two providers.

The page shows how many blanks the template has and how many SMS it will be sent as.

Send a test

Under Send a test, send one template to your own mobile. A success marks the provider Working; a refusal shows the provider’s reason, so you can fix it before a customer is waiting.

Writing templates the agent can use well

Each {#var#} takes at most 30 characters when it is sent, so keep the moving parts short: a first name, a date, a short link.

Good

Hi {#var#}, thanks for calling Acme Clinic. Book your visit here: {#var#}

Good

Your appointment at Acme Clinic is on {#var#} at {#var#}. Reply on WhatsApp to change it.

Won't work well

{#var#}

A template that is nothing but a blank was never going to pass DLT, and the agent cannot write free text into an SMS anyway. Every message is one of your approved templates, with only the blanks filled in.

Plain English fits 160 characters in one SMS. Hindi, other Indian scripts and emoji fit 70, so the same message may be sent as two or three SMS, and your provider charges for each one.

Using it

During a call or chat — tick the templates the agent may use, then turn on Send the customer an SMS on the agent’s Actions page. See Actions.
After a call — choose an SMS template in the After the call card on the same page. See After the call.

Every SMS the agent sends shows up as a note in that conversation, so your team can see what went out.

When something goes wrong

What you see	Usually means
The provider’s test fails with a DLT or template error	The text here doesn’t match the DLT template word for word, or the DLT template ID is wrong
The test succeeds but nothing arrives	Your provider isn’t in your PE–TM chain yet, or the sender ID isn’t approved for that template
”SMS can only be sent to an Indian mobile number”	The customer’s number is a landline or outside India
”MSG91 needs the MSG91 template ID”	Add the template on MSG91’s dashboard too, and paste its ID
Can’t change a template’s text	An agent sends it after calls and fills a different number of blanks. Change that agent’s After the call first

From the API

Everything above is also in the API: SMS.

curl -X POST https://app.thinnest.ai/api/v1/sms/templates \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "booking_link",
    "body": "Hi {#var#}, thanks for calling Acme Clinic. Book your visit here: {#var#}",
    "dltTemplateId": "1207169876543210987",
    "category": "service_implicit"
  }'

Getting started

Your agent

Channels

Put it on your site

Reaching out

Meta's rules

Working the conversations

White label

Partners

What DLT asks of you first

Providers you can connect

Connect

Writing templates the agent can use well

Using it

When something goes wrong

From the API

​What DLT asks of you first

​Providers you can connect

​Connect

​Writing templates the agent can use well

​Using it

​When something goes wrong

​From the API

What DLT asks of you first

Providers you can connect

Connect

Writing templates the agent can use well

Using it

When something goes wrong

From the API