Every messaging term, defined.
DLT, PE, BSP, conversation, template, DLR, scrubbing — the full vocabulary of Indian messaging, written in plain English for everyone on the team.
Most looked-up
Ten terms worth knowing cold.
DLT
Distributed Ledger TechnologyIndia's blockchain-based registration system for commercial SMS senders, mandated by TRAI.
Principal Entity
PEThe business — the actual brand sending SMS — registered on a DLT operator portal.
BSP
Business Solution ProviderA Meta-approved partner that provides access to the WhatsApp Business API.
OTP
One-Time PasswordA short-lived numeric or alphanumeric code used to verify a user.
WhatsApp template
A pre-approved WhatsApp message format required to start a conversation outside the 24-hour window.
Conversation (WhatsApp)
A 24-hour billing unit on the WhatsApp API — priced by template category.
Header
The six-character alphanumeric sender ID that shows up on the recipient's phone.
DND
Do Not DisturbA subscriber preference registered with the operator to block commercial messages.
DLR
Delivery ReceiptA status callback from the operator SMSC confirming what happened to a sent SMS.
Idempotency key
A unique request ID that guarantees an OTP send isn't duplicated on a retry.
Pick the area you're working in.
Each category is self-contained, but every term links to its neighbours.
Compliance & DLT
TRAI, DLT, consent and scrubbing vocabulary for India.
SMS
Message types, encoding, segmentation and delivery.
WhatsApp Business
BSP, templates, sessions and number quality.
OTP & Authentication
OTP, 2FA, retries and fallbacks.
Delivery & Routing
Operators, SMPP, DLRs and throughput.
API & Integration
Webhooks, SDKs, sandboxes and message IDs.
Pricing & Billing
Wallets, invoicing, GST and credits.
AI Agents
Intents, handoff, guardrails and knowledge bases.
A – Z
The full glossary.
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