HostMentor Docs

The 24-hour window

WhatsApp's 24-hour customer service window: when you can send any message, and when you must send an approved template instead.

WhatsApp lets businesses send free-form messages only to customers who have written recently.

  • When a customer messages you, a 24-hour customer service window opens for that customer. Each new message from them restarts it.
  • Inside the window you can send any type of message: text, media, buttons, lists, products, payment requests, reactions and templates.
  • Outside the window you can only send templates. These are message formats that WhatsApp has approved in advance. Anything else fails with error 131047.

So to contact a customer first, or after more than a day of silence, send a template. When they reply, the window opens and you can chat freely.

IDs and phone numbers

The IDs you use with the WhatsApp Business API, from phone_number_id and waba_id to message, media, template and catalog IDs, and how to write phone numbers.

Webhooks

Receive incoming WhatsApp messages and delivery statuses on your webhook, verify the X-HostMentor-Signature header, and handle retries and duplicates.