WhatsApp has an official "Coexistence" feature that lets you use the Cloud API and the Business App on the same number at the same time. Most people don't know it exists.
Took me an embarrassing amount of time to figure this out, so sharing here in case it saves someone the headache.
Most small business owners I've talked to hit the same wall. They start sending WhatsApp messages manually or through some browser extension, eventually get flagged by Meta, then look into the official Cloud API as the safe alternative. Then they find out switching to the API means losing the WhatsApp Business App on their phone. So they drop the whole idea.
That last part isn't actually true anymore.
Meta has a feature called Coexistence. It lets the same phone number run on both the Cloud API and the WhatsApp Business App simultaneously. Your automations go through the API. A client replies at 11pm, it hits your phone like a normal message. You reply from the app. The API picks back up.
Setting it up is not simple. The registration flow is confusing and Meta's documentation for small business owners is genuinely thin. The sequence of steps matters a lot. Connect the number to the API in the wrong order and you can end up stuck in a loop where the Business App won't recognize the number again. Chat history can disappear in this process.
Once it's working though, the API lets you send approved broadcast templates at real volume, connect tools like Make or Spur to trigger messages off CRM events, and pipe conversations into team inboxes so your whole team can handle replies without sharing one phone. The coexistence feature just means you keep the personal channel open alongside all of that.
If you're currently on an unofficial setup and sending more than a few dozen messages a day, it's worth sorting this out before Meta restricts the number. Recovering a flagged number when WhatsApp is your main customer channel is not a fun situation to be in.