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WhatsApp Business API glossary for developers

The terms you meet when you integrate the WhatsApp Business API, defined in a line each: what the word means at Meta, and what it changes for your code.

Updated November 10, 2026Read as Markdown

TermDefinition
WABAWhatsApp Business Account: the account at Meta that owns one or more business numbers, their templates and their payment method.
Cloud APIMeta's hosted WhatsApp API, the official one. Numbers are registered on it; messages go through Meta's servers.
Phone number IDThe identifier Meta gives to a business number, distinct from the number itself. Calls to Meta name the number by this id.
TemplateA message approved by Meta in advance. The only way to write first, or after the 24-hour window has closed.
Customer service windowThe 24 hours after a customer's last message, during which you may answer in free text.
Message categoryMarketing, utility, authentication or service: what decides the price of a message. See Meta's pricing.
Messaging tierThe number of different customers a business number may write to first in 24 hours. It rises with the number's quality.
Quality ratingMeta's measure of how customers receive a number's messages (green, yellow, red). A red rating can lower the tier.
Embedded SignupMeta's signup window, shown inside a partner's product, through which a business connects its number. See the connect link.
Tech ProviderA partner that onboards businesses through Embedded Signup, while each business pays Meta directly. See Tech Provider or Solution Partner.
Solution Partner (BSP)A partner that can also pay Meta on a line of credit and bill its customers. Formerly Business Solution Provider.
CoexistenceA number used at once on the WhatsApp Business app and on the API. See coexistence.
FlowA form that opens inside a WhatsApp conversation. See Flows.
WebhookAn HTTPS address of yours that the gateway calls for each event: a message received, a status changed.
Idempotency keyA value you choose per message; sending twice with the same key sends once.
E.164The international phone number format: a plus sign, the country code, then the number (+33612345678).

Frequently asked questions

What is a WABA?

A WhatsApp Business Account: the account at Meta that owns a business's WhatsApp numbers, their templates and their payment method.

What is the difference between the Cloud API and the WhatsApp Business app?

The Cloud API is the programmatic interface, for software. The WhatsApp Business app is the phone app, for a person. With coexistence, one number can use both.

Try it with your own number.

Build is free: 3,000 messages a month, no card.

Talk to the Nodium team

Tell us what you are connecting. We get back to you within one business day, with a price that fits your WhatsApp numbers and your volume.