Yes. Twilio supports WhatsApp through the WhatsApp Business Platform, using its Programmable Messaging and Conversations APIs. You'll need a registered WhatsApp sender, user opt-in, and pre-approved templates for business-initiated messages outside a 24 hour customer service window. A Sandbox is available for testing first.
Twilio lets you send and receive WhatsApp messages through the WhatsApp Business Platform and its own APIs. The uses it lists are support, notifications, verification and promotions. Before you plan a campaign, though, WhatsApp's rules shape what you can send and when.
Picking the right API
| You want to | Use |
|---|---|
| Send one-way notifications, such as order updates | Programmable Messaging API |
| Run two-way conversations with customers | Conversations API |
| Prototype and test before registering | Twilio Sandbox for WhatsApp |
In the API, WhatsApp addresses use the format whatsapp: followed by the phone number in E.164 format, so your code needs to store numbers in that format from the start.
Getting a sender registered
To send messages under your own brand, you must register a WhatsApp sender: a phone number tied to a WhatsApp Business Account, known as a WABA. Direct customers register with WhatsApp Self Sign-up. Independent Software Vendors, building messaging for their own clients, use the WhatsApp Tech Provider Program instead.
Two numbers matter here. Only one WABA is allowed per Twilio account. And businesses without a verified Meta Business Manager are allowed a maximum of 2 phone numbers; with verification it's up to 20, and an exception up to 50 can be requested. If you run several brands or locations, get the Meta verification done early.
The three rules that decide what you can send
Opt-in comes first
WhatsApp requires explicit user opt-in. Sending without it may lead to users blocking you and, ultimately, suspension of your WhatsApp Business account. Build the opt-in into your checkout, sign-up or booking form, and keep a record of it.
The 24 hour window
When a customer messages you, a customer service window opens. It lasts 24 hours after their most recent message, and inside it you can send free-form replies.
Templates everywhere else
Business-initiated notifications must be templated and pre-registered, except when you're replying to a message the user started. So an order confirmation or appointment reminder needs an approved template; a reply to a customer's question within the window doesn't.
These rules suggest a simple design. Use an approved template for the first message, such as a delivery update, and invite the customer to reply if they've got a question. The moment they do, the 24 hour window opens and your team can answer in plain, free-form messages. Every reply from the customer resets the clock, so a lively conversation can carry on for as long as it needs.
No cold messaging, and a cap on numbers
Twilio Docs, in the WhatsApp Business Platform overview, spell out the practical result: you can't cold-message on WhatsApp through Twilio. Outside the 24 hour window only pre-approved templates work, and without a verified Meta Business Manager you're capped at 2 phone numbers. For a small business, that means WhatsApp is best for customers who've already chosen to hear from you, not for prospecting.
If you're weighing whether the API route is right for your size of business, this guide on whether the Twilio WhatsApp API is worth it for a small business goes through the trade-offs.
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Testing before you register
The Twilio Sandbox for WhatsApp lets you prototype and test sending and receiving messages before your sender is approved. Use it to build and check your templates, opt-in flow and replies, so the switch to your registered number is just a change of sender.
Another provider with the same rules
Vonage's Messages docs describe the same 24 hour customer care window and say templates must be approved by WhatsApp before use. The rules come from WhatsApp, not the provider, so switching providers won't get you round them. For other options, see my list of Twilio alternatives, or if you'd rather not code at all, these WhatsApp chatbot builders sit on top of the same platform.
My advice before you build
Start in the Sandbox, write your templates and opt-in wording, and get Meta Business Manager verification under way at the same time. Use the Programmable Messaging API for notifications and the Conversations API for support. Treat the 24 hour window as your service promise: answer fast, and you can reply freely.
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Frequently asked questions
Can I use my own number with Twilio WhatsApp?
Twilio links to a support guide on activating your own phone number; the overview page covers registering a sender through Self Sign-up.
Can I test without registering?
Yes. The Twilio Sandbox for WhatsApp is for prototyping and testing.
Do I need templates?
Yes, for business-initiated messages outside the 24 hour customer service window.
Is opt-in required?
Yes. WhatsApp requires explicit user opt-in.
Can I run two-way chat?
Yes, with the Conversations API.
