In short: an unofficial WhatsApp API links a normal WhatsApp number to your software, so you send and receive from your own number without Meta’s approval or per-message fees. WhatsApp does not endorse these services and bans numbers that spam, so they suit conversations with people who expect to hear from you, not cold bulk messaging.
Two ways to send WhatsApp messages from software
Meta’s official WhatsApp Business Platform
Meta’s own API, used directly or through a Business Solution Provider. You register a number with Meta, verify your business and send through Meta’s servers. To start a conversation, or to write to someone more than 24 hours after their last message, you use a message template that Meta has approved. Meta charges for template messages at rates set by country and category; replies within the 24-hour window are free.
A linked number, the “unofficial” API
Your number stays on your phone. The service links to it as a companion device — the way WhatsApp Web and WhatsApp Desktop link — when you scan a QR code or type a pairing code. Messages go out from your number as if you had typed them, replies come back to your system, and your phone carries on as normal. There is no approval, no template and no charge per message. TextBot works this way.
What “unofficial” means in practice
- Meta does not endorse it. Linked-device services are not part of Meta’s Business Platform, and WhatsApp’s terms do not allow bulk or automated messaging from the WhatsApp apps.
- A number can be banned. WhatsApp bans numbers for how they behave: messages people did not ask for, many blocks and reports, sudden floods of identical messages. That is true of any WhatsApp number, linked or not.
- No green tick and no templates. People see the profile your WhatsApp or WhatsApp Business app already has.
- The phone matters. WhatsApp signs out linked devices when the phone has been offline for about two weeks, or when the number is registered on another phone. You link it again with a new QR code.
How to keep a number safe
- Message people who expect it. Customers who ordered, booked, asked a question or opted in. Never send to bought or scraped lists.
- Make stopping easy, and honour it. Tell people how to opt out and take them off your list when they do. The TextBot WordPress plugin keeps opt-in records and enforces opt-outs for you.
- Send what people are waiting for. Order updates, reminders, quotes and replies get read. Unexpected promotions get blocked and reported.
- Start gently with a new number. A number registered last week that suddenly sends hundreds of messages looks like spam. Where you can, use a number with a history of normal conversations.
- Write to the person. Their name and the details of their order read better than one identical message to everyone.
- Answer the replies. Conversations that go both ways are what WhatsApp is for. Send replies to your system with a webhook, or answer them as a team in AgentDesk.
When the official platform is the better choice
- You send marketing to large lists, or thousands of messages a day.
- You need a verified business profile, or support from Meta itself.
- Your industry, or your compliance team, requires an official channel.
When your own number makes more sense
- You talk to your own customers: orders, bookings, invoices and support.
- Most of your messages are replies and updates, not cold outreach.
- You want to keep the number your customers already have saved, on your phone.
- You would rather pay a flat price than per message, and start today rather than after an approval.
- Your developers want one HTTP call, not a provider’s platform.
The two side by side
| Official Business Platform | Your own number (TextBot) | |
|---|---|---|
| Approval | Meta verifies your business and approves your templates | None: you scan a QR code |
| Starting a conversation | An approved template, outside the 24-hour window | Any message |
| Cost | Meta’s charge per template message, plus your provider’s fees | An annual plan from $30, with no per-message fees |
| The number | Registered with Meta’s platform | Stays on your phone |
| Time to start | Usually days, while verification and templates are approved | Minutes |
| The risk | Meta’s quality ratings and messaging limits | Not endorsed by Meta; numbers that spam are banned |