WhatsApp API Glossary: 50 Terms in Plain English

Tenashi Team·October 29, 2026·10 min read

WhatsApp API conversations lean on acronyms. A provider mentions your WABA, a developer asks whether the CSW is open, finance wants to know why FEP messages were free and service messages were not. Nod along without being sure, and decisions rest on wrong assumptions.

This WhatsApp API glossary defines 50 terms you will meet on Meta's WhatsApp Business Platform and in linked-number tools, each in a line or two, as they stand in October 2026. Several changed meaning this year, notably WABA, which Meta split into two account types in September.

Terms are grouped alphabetically. For how they fit together, read the complete guide to the WhatsApp API.

A to B

Access token: The credential your server sends in the Authorization header of every API call. For production, Meta recommends a long-lived token owned by a system user, a non-human account in Business Suite.
Authentication template: A template category for one-time passwords and login codes, with copy-code, one-tap and zero-tap button options. Priced separately from other categories.
Automatic scaling: Meta raising your messaging limit one level, within about 6 hours, when your quality is high and you used at least half your current limit in the last 7 days.
BSP (Business Solution Provider): A company that resells access to the official platform, usually with its own dashboard and fees. Meta's current docs call them Solution Partners.
BSUID (business-scoped user ID): An ID for a WhatsApp user that is unique to your business portfolio, such as US.13491208655302741918. It appears in webhooks since April 2026 and supports usernames. See our BSUID guide.
Business portfolio: The top-level container in Meta Business Suite, formerly Business Manager, that owns your WhatsApp assets and carries business verification.
Business verification: Meta's check that your business is real, done on the business portfolio. It unlocks higher limits, more numbers and Official Business Account eligibility.

C to E

Calling API: The Cloud API feature for WhatsApp voice calls. User-initiated calls are free; business-initiated calls need permission and are billed by duration.
Click-to-WhatsApp ad (CTWA): A Facebook or Instagram ad that opens a WhatsApp chat with your business. Replies to these chats can open a free entry point window.
Cloud API: Meta's hosted API for sending and receiving WhatsApp messages over the Graph API. The only official messaging API since the On-Premises API expired.
Coexistence: Using one WhatsApp Business app number with both the app and the Cloud API. App messages stay free; API throughput is fixed at 20 per second. See WhatsApp coexistence.
Customer service window (CSW): The 24 hours after a user's last message or call, when you can send free-form messages. Outside it, only templates. See the WhatsApp 24-hour window.
Display name: The business name shown on your WhatsApp profile. It must follow Meta's guidelines and is reviewed before it can appear at the top of chats.
Embedded Signup: Meta's onboarding popup that partners put in their product so a business can create accounts and connect a number in a few minutes.

F to L

Flows: Multi-screen forms that open inside a chat, for things like bookings, quotes and lead capture, defined in Flow JSON.
Free entry point (FEP): A window of up to 7 days, opened when you reply to a user who came from a Click-to-WhatsApp ad, during which most business messages are free.
Groups API: The Cloud API feature that lets Official Business Accounts create invite-only groups of up to 8 participants. It cannot access groups a number is already in.
Interactive message: A message with reply buttons, lists, URL buttons, location requests or Flows. Free-form interactive messages only work inside the customer service window.
Linked device: A companion device, such as WhatsApp Web, connected to a regular WhatsApp account by QR code. Linked-number tools use this mechanism rather than the official API.

M to O

Market: The recipient's country or region, set by their country calling code, which with the category decides a message's price. Meta's published rate card listed 47 markets as of October 2026.
Marketing template: The template category for promotions, offers and re-engagement. The most expensive category, with no volume discounts.
Marketing Messages API (MM API): Meta's separate API for marketing templates, with delivery optimization and conversion metrics. It becomes the only API route for marketing on October 13, 2027.
Messaging account: The account that holds templates, billing and webhook subscriptions since Meta's September 2026 change. It keeps your old WABA ID.
Messaging limit: How many unique users your business portfolio can message outside a customer service window in a moving 24 hours: 250, 2,000, 10,000, 100,000 or unlimited. See messaging limits.
Meta Business Agent: Meta's own AI customer-service agent for WhatsApp, Messenger and Instagram, priced per token and launched globally in June 2026.
Official Business Account (OBA): A verified business number with a blue checkmark beside its name. Requires business verification, an approved display name and 30 days on the platform.
On-Premises API: The retired self-hosted version of the WhatsApp Business API. Its final version expired on October 23, 2025.
Opt-in: The permission a person gives to receive messages from your business, which Meta's policy requires before you message them.

P to S

Pair rate limit: The cap on messages from one business number to the same user: one every 6 seconds, with short bursts allowed. Exceeding it returns error 131056.
Per-message pricing: Meta's billing model since July 1, 2025: each delivered message is charged by category and market, replacing the old 24-hour conversation pricing.
Per-user marketing limit: WhatsApp's cap on how many marketing templates a person receives from all businesses when they seem unlikely to engage. Blocked sends fail with 131049.
Phone number ID: The numeric ID of your registered business number, used in every send URL. It is not the phone number itself.
Quality rating: WhatsApp's score of how users receive your messages over the last seven days, based on blocks, reports, mutes and archives. See quality rating.
Service message: A free-form, non-template reply inside the customer service window. Since October 1, 2026, the first 1,000 per number each month are free.
Solution Partner: A Meta partner that onboards businesses and can share its credit line to bill them. Most companies called BSPs are Solution Partners.

T to Z

Tech Provider: A software company that onboards its own customers to the platform through Embedded Signup, while each customer pays Meta directly.
Template: A message format pre-approved by Meta, with a header, body, footer and buttons, and the only kind allowed outside the customer service window. Meta can later recategorize it, changing its price.
Template pausing: Meta automatically pausing a low-quality template for 3 hours, then 6 hours, and disabling it on the third occurrence.
Throughput: How many messages per second a number can handle: 80 by default, upgradable to 1,000. Exceeding it returns 130429. See throughput.
Unofficial API: Any software that automates a regular WhatsApp account outside Meta's platform, usually through the linked-device protocol. Not endorsed by Meta.
Utility template: The template category for updates about a transaction or account the user started, such as orders, deliveries and appointments.
Volume tiers: Lower per-message rates that kick in at higher monthly volumes, for utility and authentication messages only, per market and reset monthly.
WABA (WhatsApp Business Account): The account that used to hold a business's numbers, templates and billing. Since September 2026 it is split into a WhatsApp account and a Messaging account. See our WABA guide.
WhatsApp account (WAAC): The account that holds one business phone number, its display name and profile under the new model. Always owned by the business.
wa_id: A user's WhatsApp ID, usually their phone number in digits. It may be missing for users who adopt usernames, which is why BSUIDs exist.
wamid: The ID of a single WhatsApp message, returned when you send and repeated in every status webhook for that message.
Webhook: An HTTPS endpoint you host that Meta calls with inbound messages, delivery statuses and account events. Meta retries failed deliveries for up to 7 days.
WhatsApp Business app: The free phone app for small businesses, run by people. It is separate from the API platform, apart from coexistence.
WhatsApp Manager: The web interface in Meta Business Suite for managing numbers, templates, messaging limits and insights.
X-Hub-Signature-256: The header on every Cloud API webhook carrying an HMAC-SHA256 of the raw body, made with your app secret. Verify it before trusting the payload.

Where Tenashi fits

Most of this glossary describes Meta's official platform. One term, linked device, describes where Tenashi sits. You link the WhatsApp or WhatsApp Business number you already use by QR scan, and your team works it from one shared inbox of DMs and groups, with a CRM, tickets and follow-ups under every chat. So a good share of these terms simply do not apply: there are no templates, customer service windows, categories or per-message fees.

Its developer vocabulary is small: conversationId to send into an existing DM or group, Idempotency-Key to stop duplicate sends, and webhook events such as message.received. The limit: Tenashi is not Meta's platform, so it has no green tick, interactive messages or OTP-grade speed. Plans start from $18/mo.

Read the API docs · See every feature

FAQ

What does WABA stand for?

WABA stands for WhatsApp Business Account, the account on Meta's platform that held a business's numbers, templates and billing. Since September 2026 Meta has split it into a WhatsApp account, which holds a phone number, and a Messaging account, which holds templates and billing. The old WABA ID now identifies the Messaging account.

What is the difference between a BSP and a Tech Provider?

Both are Meta partners that onboard businesses through Embedded Signup. A BSP, which Meta calls a Solution Partner, can share its own credit line and bill customers for messages. A Tech Provider builds software that connects to the platform, but each customer adds its own payment method and pays Meta directly.

What is a template message on WhatsApp?

A template message is a pre-approved message format on Meta's platform, categorized as marketing, utility or authentication. It is the only kind of message a business can send outside the 24-hour customer service window. Each template is reviewed by Meta, can include variables and buttons, and is billed by its category.

What is a linked device on WhatsApp?

A linked device is a companion, such as WhatsApp Web or desktop, connected to a regular WhatsApp account by scanning a QR code on the phone. It sends and receives as that account. Linked-number tools use this same mechanism to give teams access to an existing number without Meta's official API.

What does CSW mean in WhatsApp API?

CSW stands for customer service window, the 24 hours after a user last messaged or called your business number. While it is open you can send free-form messages; when it closes, only templates are allowed. Since October 2026, replies inside it are free only for the first 1,000 per number per month.

Bookmark this page for your next vendor call. When you are ready to put the terms to work on your own number, get started with Tenashi.

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