24-hour window (customer service window)
The 24 hours after a customer’s last message. During that time the business can reply freely; afterwards it can only write to them with a Meta-approved message template.
The 24-hour window explained →WhatsApp Business glossary
The WhatsApp Business terms you will meet when you move to the API, each defined in one or two sentences from Meta’s official documentation, with a link to the WYP.chat page that covers it in more depth.
Message template
A message prepared in advance and approved by Meta, the only way to message a customer first or after the 24-hour window. It can include variables, a header and buttons.
WhatsApp campaigns →Template categories: marketing, utility, authentication
Every template has a category, which sets its price: marketing (offers, promotional reminders), utility (updates on an order or appointment) and authentication (one-time codes). Meta can recategorise a template.
Template categories explained →Service message
A free-form reply from the business within the 24-hour window. Since 1 October 2026, 1,000 delivered service messages are free per month and per number, then charged at the country’s utility rate.
What is free and what is paid →WhatsApp Business API (Cloud API)
Meta’s official way to connect a WhatsApp number to software, so a team can reply together, automate and send campaigns. The Cloud API, its current version, is hosted by Meta.
The WhatsApp Business API explained →WhatsApp Business account (WABA) and business portfolio
The WhatsApp Business account holds your numbers and templates; it belongs to your Meta business portfolio (formerly Business Manager), where verification and the payment method are also managed.
Connecting your number →Embedded Signup
Meta’s window, opened inside a piece of software, that connects a number to the API without a developer: the business picks its portfolio, WhatsApp Business account and number, which stay its own.
The connection steps →Coexistence
The same number works both in the WhatsApp Business app on the phone and on the API, inside software such as WYP.chat. Contacts and recent history are carried over; the app must be opened regularly.
Coexistence with WYP.chat →WhatsApp username and BSUID
A customer can choose a username instead of showing their number. Meta then sends an identifier specific to each business portfolio, the BSUID (for example “GB.” followed by digits), used to reply without knowing their number.
WhatsApp usernames for businesses →Opt-in (consent)
The customer’s agreement to receive messages from the business on WhatsApp, required by Meta before messaging them first, especially for marketing. It must be collected clearly and can be withdrawn at any time.
WhatsApp consent: rules and wording →Messaging limit
How many different customers a portfolio can message outside the service window in a rolling 24 hours: 250 for a newly created business portfolio, then 2,000, 10,000, 100,000 and unlimited.
Messaging limits explained →WhatsApp catalogue
The list of your products, managed in Meta’s Commerce Manager and linked to the number. The customer browses the items, fills a basket and sends it in the conversation.
The WhatsApp Business catalogue guide →Sources
- Meta, non-template messages and the service window: developers.facebook.com/documentation/business-messaging/whatsapp/pricing/non-template-messages
- Meta, message templates: developers.facebook.com/documentation/business-messaging/whatsapp/templates/overview/
- Meta, template categorisation: developers.facebook.com/documentation/business-messaging/whatsapp/templates/template-categorization/
- Meta, WhatsApp Business Platform: developers.facebook.com/documentation/business-messaging/whatsapp
- Meta, Embedded Signup: developers.facebook.com/documentation/business-messaging/whatsapp/embedded-signup/overview
- Meta, coexistence with the WhatsApp Business app: developers.facebook.com/documentation/business-messaging/whatsapp/embedded-signup/onboarding-business-app-users/
- Meta, business-scoped user IDs (BSUID): developers.facebook.com/documentation/business-messaging/whatsapp/business-scoped-user-ids/
- Meta, getting opt-in: developers.facebook.com/documentation/business-messaging/whatsapp/getting-opt-in/
- Meta, messaging limits: developers.facebook.com/documentation/business-messaging/whatsapp/messaging-limits
- Meta, catalogues: developers.facebook.com/documentation/business-messaging/whatsapp/catalogs/catalogs-overview/
Meta documentation checked on 10 and 11 October 2026.
WYP.chat applies these Meta rules when you create templates and when you send
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