What phone number can you use for the WhatsApp Business API?
You need a number you control, that can receive a verification code by SMS or voice call, and that is not currently active on the WhatsApp consumer app or the WhatsApp Business app. A landline works as long as it can take the verification call. Once a number is registered to the Business Platform it can no longer be used in either phone app.
The one-number-one-place rule
A number lives in exactly one of three places: the consumer app, the Business app, or the Business Platform. It cannot be in two.
This is the detail that catches businesses out. Moving your existing Business app number to the API means that number stops working in the app on the phone — including its chat history, which does not come with it.
If people are actively using the phone app to serve customers on that number, migrate deliberately, not on a Friday afternoon.
Using a new number instead
Registering a fresh number avoids the migration entirely, at the cost of the recognition your existing number has.
A new number starts with no messaging history, which means the lowest messaging tier and no established quality rating. That is not a penalty, just a starting point.
What the number cannot be
A number you do not control — you must be able to receive the verification code on it.
A shortcode. Those cannot be registered.
A number already registered to another WhatsApp Business account, including one a previous provider set up on your behalf. If a provider registered your number under their business account, releasing it is their action, not yours.
The display name is separate
The name customers see is reviewed by Meta. It does not have to match the number, but it does have to relate to your business.
It can be changed later, though changes are reviewed again and frequent changes are treated as a signal.
PingPlug connects to a WhatsApp Business account registered under your own Meta business, so the number stays yours and the release problem above does not arise if you leave.