What do I need to connect a number through WhatsApp Coexistence?

In short: the WhatsApp Business app on the number, version 2.24.17 or newer and in regular use, a Facebook account with two-factor authentication, and a computer to run the connection with your phone at hand. No CNPJ or company registration is needed to connect.

The checklist

• The number runs on the WhatsApp Business app (not regular WhatsApp), on Android or iPhone, version 2.24.17 or newer. This is the only requirement Meta publishes.
• The number is in regular use. Meta may refuse numbers with little recent activity and does not publish the threshold; in practice about 7 days of real use has been enough.
• A personal Facebook account with two-factor authentication on. It is only used to authorize the connection.
• The number is not connected to another provider (how to move it).
• A computer to run the connection, with your phone at hand to confirm it in the WhatsApp Business app.

Inside Meta's window

• If Meta asks for a phone number first, type or pick the number of your WhatsApp Business app, and go on only if Meta then shows that app's profile. If it shows two options, choose Connect a WhatsApp Business app, never Create a WhatsApp Business account.
• Stop if Meta sends a code by text message or phone call and asks you to type it, or asks you to delete your account: Coexistence needs neither (why).
• If Meta says the number is already registered, pick it from the list on the phone number screen instead of typing it. Still refused? Update the app, disconnect any provider you no longer use under Settings > Account > Business Platform and wait 15 minutes.
• A security check about a new device or location keeps the Next button spinning until you clear it at business.facebook.com, in the same browser (how to clear it).
• Meta checks eligibility here, before anything is authorized. If it refuses the number, ZapClaw receives no access; see number not eligible.
• If Meta answers that this number can't be shared with this app, it gives ZapClaw no reason; see number can't be shared for what to check and how to ask Meta.
• The app asks whether to share your chat history. It is optional; the contact list is always synced.

After connecting

• Linked devices are disconnected and can be linked again, except WhatsApp for Windows and WearOS, which Meta does not support with Coexistence.
• Keep opening the app on your main phone: Meta disconnects the number after about 14 days without it.
• Meta turns off disappearing messages, view-once and live location in one-to-one chats, broadcast lists become read-only, and group chats are not synchronized to the API.
• A Coexistence number sends up to 20 messages per second, a limit Meta fixes.