Messaging glossary: the terms explained

A2P SMS

Application-to-person SMS: messages sent by software, such as OTPs, alerts and campaigns, to a person's phone. Bulk and business SMS is A2P. Learn more

API

A way for your software to talk to ours. With an SMS or WhatsApp API, your website or app can send messages automatically. Learn more

Authentication template

The WhatsApp template category for one-time passwords. It holds only the code and a short warning, with a copy code button. Learn more

Bounce

An email that could not be delivered. A hard bounce is permanent, such as an address that does not exist. A soft bounce is temporary, such as a full mailbox. Learn more

Carousel

A rich message with several cards that the person swipes through. Used in RCS and some WhatsApp messages. Learn more

Consent

A person's agreement to receive your messages. Promotional SMS, WhatsApp marketing and marketing email all depend on it. Learn more

Content template

The registered wording of an SMS, with variables for the parts that change. Each approved template has its own template ID. Learn more

Delivery report (DLR)

A status for each message, such as delivered or failed, sent back after you send. It shows what reached the phone. Learn more

DKIM

DomainKeys Identified Mail: a digital signature that proves an email was sent by your domain and not changed on the way. Learn more

DLT

Distributed Ledger Technology: the platform on which Indian telecom operators register businesses, sender IDs and message templates for commercial SMS. Learn more

DMARC

A policy that tells mail providers what to do with email that fails SPF or DKIM checks, and reports on it. Learn more

DND

Do Not Disturb: the national register of numbers whose owners have blocked promotional messages and calls. Learn more

DTMF

Dual-tone multi-frequency: the tones made when a caller presses keys on the phone. IVR and voice campaigns use them to capture responses. Learn more

Entity ID

The number a telecom operator gives your business when it is registered on DLT. Also called the principal entity ID. Learn more

Header (sender ID)

The short name that appears as the sender of an SMS, such as a brand name. It is registered and approved before use. Learn more

IVR

Interactive Voice Response: an automated phone menu that answers calls and routes callers by key press or voice. Learn more

Merge field

A placeholder, such as a name or order number, that is replaced with each person's own details when a message is sent. Learn more

Missed call service

A service where customers give a free missed call to a number and the system follows up with an SMS or callback. Learn more

OBD

Outbound dialling: automated calls that play a recorded message to many numbers. Also called voice broadcasting. Learn more

OTP

One-time password: a short code that works once and expires quickly, used to verify login, sign-up or payment. Learn more

Promotional SMS

A marketing text message, such as an offer. It respects DND choices and is sent only during permitted hours. Learn more

RCS

Rich Communication Services: a richer kind of text message with images, carousels and buttons in the default messaging app. Learn more

SMPP

Short Message Peer-to-Peer: a protocol that lets large senders connect their systems directly to an SMS gateway for high-speed sending. Learn more

SMTP

Simple Mail Transfer Protocol: the standard way email is sent between servers and applications. Learn more

SPF

Sender Policy Framework: a record that lists which servers may send email for your domain. Learn more

Template ID

The number given to an approved SMS template. It is attached to each message so it can be matched with the template. Learn more

TRAI

The Telecom Regulatory Authority of India, which sets the rules for commercial messages and calls in India. Learn more

Transactional SMS

An automatic text triggered by a customer's action, such as an order or payment. It can reach DND numbers but cannot carry offers. Learn more

Unicode SMS

An SMS in a language that needs special characters, such as Hindi or Marathi. It fits 70 characters per message instead of 160. Learn more

Utility message

The WhatsApp template category for updates about something a customer did, such as an order or appointment. Learn more

Webhook

A way for our platform to tell your system when something happens, such as a message being delivered or a customer replying. Learn more

WhatsApp Business API

The version of WhatsApp for businesses that message at scale and connect to software, using approved templates. Learn more