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.
phone_number_id: your WhatsApp number. It sends messages and owns media files. It's an ID, not the phone number itself. Find it on the dashboard or with List your phone numbers.waba_id: your WhatsApp Business Account, which owns your templates. It comes back from the same call aswhatsapp_business_account_id.- Message ID: one message, sent or received. Starts with
wamid.. It comes back when you send, and in webhooks. - Media ID: a file uploaded to WhatsApp or received from a customer. It comes back from Upload media and in incoming-message webhooks.
- Template ID: one message template. It comes back when you create or list templates.
catalog_id: your product catalog. Get it with Retrieve your catalog ID.
Phone numbers
Write customer numbers with the country code and no +, spaces or dashes. For example, the Indian mobile number +91 98765 43210 is 919876543210.
In webhooks, a customer's number arrives as their WhatsApp ID (wa_id), usually in the same format. You can send to a wa_id directly.
Base URL and versions
The WhatsApp API base URL is https://wa.hostmentor.com/v3. How v3 stays stable, what counts as a breaking change and how much notice you get.
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.