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Business messaging glossary
Plain-English definitions for WhatsApp, SMS, email and automation terms.
Short, plain definitions of the terms used across WhatsApp, SMS, email and automation. Each term links to the page that explains it in context.
- A2P SMS
- Application-to-person SMS: messages sent by software (a business system) to a person, such as OTP codes, alerts and campaigns. It is regulated differently from person-to-person texting in many countries.
- BSP (Business Solution Provider)
- A company approved by Meta to give businesses access to the WhatsApp Business Platform, handle onboarding and provide tools on top of the API.
- Customer service window
- The 24 hours after a customer last messaged your business on WhatsApp. Inside it you can send free-form replies; outside it you can only send approved template messages.
- DLT
- Distributed Ledger Technology registration, required in India by TRAI. Businesses register their entity, sender header and message templates before sending commercial SMS.
- HLR lookup
- A real-time query to the mobile network that shows whether a number is active, its network and whether it was ported. Used to clean lists before sending.
- Marketing, utility and authentication templates
- The three template categories on WhatsApp. Marketing promotes, utility confirms or updates something the customer asked for, and authentication delivers one-time passcodes.
- Opt-in
- A customer's clear permission to receive messages from your business on a given channel. WhatsApp requires it, and many countries require it for SMS and email.
- OTP
- One-time password: a short code sent by SMS or WhatsApp to verify a login, payment or sign-up.
- Sender ID
- The name or number that appears as the sender of an SMS. Several countries, including the UAE, require sender IDs to be registered before use.
- Template message
- A pre-written WhatsApp message with fixed text and placeholders, approved by Meta, that a business can send to start or restart a conversation.
- WABA (WhatsApp Business Account)
- The account that holds your WhatsApp phone numbers, templates and messaging limits on the WhatsApp Business Platform.
- WhatsApp Business API
- The programmatic interface of the WhatsApp Business Platform for medium and large senders. It supports templates, automation, multiple agents and integrations, unlike the free WhatsApp Business app.
- 10DLC
- 10-digit long code registration used in the United States for application-to-person messaging over standard local numbers.