# 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.

| Term | Definition |
| --- | --- |
| WABA | WhatsApp Business Account: the account at Meta that owns one or more business numbers, their templates and their payment method. |
| Cloud API | Meta's hosted WhatsApp API, the official one. Numbers are registered on it; messages go through Meta's servers. |
| Phone number ID | The identifier Meta gives to a business number, distinct from the number itself. Calls to Meta name the number by this id. |
| Template | A message approved by Meta in advance. The only way to write first, or after the [24-hour window](https://nodium.io/en/guides/24-hour-window) has closed. |
| Customer service window | The 24 hours after a customer's last message, during which you may answer in free text. |
| Message category | Marketing, utility, authentication or service: what decides the price of a message. See [Meta's pricing](https://nodium.io/en/guides/meta-pricing). |
| Messaging tier | The number of different customers a business number may write to first in 24 hours. It rises with the number's quality. |
| Quality rating | Meta's measure of how customers receive a number's messages (green, yellow, red). A red rating can lower the tier. |
| Embedded Signup | Meta's signup window, shown inside a partner's product, through which a business connects its number. See [the connect link](https://nodium.io/en/features/embedded-signup). |
| Tech Provider | A partner that onboards businesses through Embedded Signup, while each business pays Meta directly. See [Tech Provider or Solution Partner](https://nodium.io/en/guides/tech-provider-vs-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. |
| Coexistence | A number used at once on the WhatsApp Business app and on the API. See [coexistence](https://nodium.io/en/features/coexistence). |
| Flow | A form that opens inside a WhatsApp conversation. See [Flows](https://nodium.io/en/features/flows). |
| Webhook | An HTTPS address of yours that the gateway calls for each event: a message received, a status changed. |
| Idempotency key | A value you choose per message; sending twice with the same key sends once. |
| E.164 | The 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.

Updated 2026-11-10 · https://nodium.io/en/guides/whatsapp-api-glossary