How to Send a WhatsApp Message via API: A Developer’s Guide to the Cloud API

• A Meta developer account and an app of type Business, created at developers.facebook.com.
• A Meta business portfolio (formerly Business Manager) that owns the app and your WhatsApp Business Account (WABA).
• A phone number that can receive an SMS or voice call for verification and is not active on the WhatsApp or WhatsApp Business app. For testing, Meta gives you a test number and lets you message a few verified recipients.
• A payment method on the WABA before sending beyond test limits, because Meta bills per delivered message.
• An HTTPS endpoint you control, if you want to receive replies and delivery statuses (webhooks).

If you have not set up the business side yet, start with how to get the WhatsApp Business API and the overview in WhatsApp Business API: the complete guide.

In your app’s WhatsApp section, Meta shows two values you need for every request:

• Phone number ID — the ID of the sending number (not the number itself).
• WhatsApp Business Account ID — used for managing templates.

The page also offers a temporary access token, valid for about a day — fine for a first test, useless in production. For anything real, create a system user in your business portfolio, assign it the app and the WABA, and generate a permanent token with the whatsapp_business_messaging and whatsapp_business_management permissions. Store it like a password: in an environment variable or secret manager, never in front-end code or a repository.

A message your business starts must be a template Meta has approved. Every new WABA comes with a sample template called hello_world, so the first request can use it:

curl -X POST "https://graph.facebook.com/{API-VERSION}/{PHONE-NUMBER-ID}/messages" \
  -H "Authorization: Bearer {ACCESS-TOKEN}" \
  -H "Content-Type: application/json" \
  -d '{
    "messaging_product": "whatsapp",
    "to": "919876543210",
    "type": "template",
    "template": { "name": "hello_world", "language": { "code": "en_US" } }
  }'

Replace {API-VERSION} with the current Graph API version shown in Meta’s docs, {PHONE-NUMBER-ID} with your phone number ID, and the to value with the recipient’s number in international format — country code first, no plus sign, no spaces, no leading zero. A successful response returns a message ID:

{
  "messaging_product": "whatsapp",
  "contacts": [{ "input": "919876543210", "wa_id": "919876543210" }],
  "messages": [{ "id": "wamid.HBgM..." }]
}

Keep that wamid: delivery and read statuses for this message will arrive on your webhook with the same ID.

Real templates carry variables — the customer’s name, an order number, a date. Create the template in WhatsApp Manager (or via the management API), wait for approval, then fill the variables in the components array:

{
  "messaging_product": "whatsapp",
  "to": "919876543210",
  "type": "template",
  "template": {
    "name": "order_confirmation",
    "language": { "code": "en" },
    "components": [{
      "type": "body",
      "parameters": [
        { "type": "text", "text": "Priya" },
        { "type": "text", "text": "#10482" }
      ]
    }]
  }
}

Parameters fill the template’s {{1}}, {{2}} placeholders in order. Templates can also have a header (text, image, video or document) and buttons, each filled through its own component. The template’s category — marketing, utility or authentication — is set when you create it and decides the price. Check a template against Meta’s rules before submitting it with the WhatsApp template checker.

When a customer messages your number, a 24-hour customer-service window opens. Inside it you can reply with any message type, no template needed:

{
  "messaging_product": "whatsapp",
  "to": "919876543210",
  "type": "text",
  "text": { "body": "Thanks for your message! Your order #10482 ships today." }
}

The same window allows images, documents, locations and interactive messages with reply buttons or lists. Outside the window — or to someone who has never written to you — a free-form message is rejected and you must use a template. A common pattern is: template to start, free-form while the customer is chatting, template again if they go quiet for more than a day.

Inside the 24-hour window you can send richer messages with the same endpoint. An image with a caption:

{
  "messaging_product": "whatsapp",
  "to": "919876543210",
  "type": "image",
  "image": { "link": "https://example.com/invoice-preview.png", "caption": "Your invoice for order #10482" }
}

An interactive message with up to three reply buttons, useful for confirmations:

{
  "messaging_product": "whatsapp",
  "to": "919876543210",
  "type": "interactive",
  "interactive": {
    "type": "button",
    "body": { "text": "Confirm your appointment on Saturday at 10:30?" },
    "action": { "buttons": [
      { "type": "reply", "reply": { "id": "confirm", "title": "Confirm" } },
      { "type": "reply", "reply": { "id": "reschedule", "title": "Reschedule" } }
    ] }
  }
}

When the customer taps a button, your webhook receives the button's id, so your code knows which choice they made without parsing free text. Documents (PDF invoices, tickets) use "type": "document" with a link and a filename.

Sending is half the job. To see replies and know whether each message was delivered or read, subscribe your app to the WhatsApp Business Account’s messages webhook field and give Meta an HTTPS callback URL.

1. Verification. Meta first sends a GET request with hub.mode, hub.verify_token and hub.challenge. If the token matches the one you configured, respond with the challenge value.
2. Events. After that, Meta POSTs JSON for each incoming message (in value.messages) and each status change — sent, delivered, read, failed (in value.statuses), keyed by the wamid.
3. Respond fast. Return HTTP 200 quickly and process the event in the background; slow or failing endpoints get retried.
4. Check the signature. Verify the X-Hub-Signature-256 header with your app secret before trusting a payload.

• Re-engagement / outside the window. You sent free-form text to someone whose last message is more than 24 hours old. Send a template instead.
• Recipient not in allowed list. On a test number you can only message numbers you added as test recipients.
• Template does not exist or is not approved. Check the exact name, the language code (en vs en_US) and the approval status.
• Parameter count mismatch. The number of parameters must match the placeholders in the approved template.
• Invalid or expired token. The temporary token expired; switch to a system-user token.
• Rate or messaging limits. Your number has a daily cap on how many different customers you can start conversations with, which rises as your quality rating stays high.
• Payment issue. No valid payment method on the WABA once you are past test usage.

Every error response includes a code and message — log them, and alert on the ones that mean a customer did not get something important.

• Queue your sends. Put outgoing messages on a queue and send at a steady rate, so a burst (a big sale, a batch of OTPs) does not hit rate limits.
• Retry carefully. Retry on network errors and throttling with back-off, but not on validation errors — those will fail every time.
• Store the wamid. Save each message ID against your order or user, so delivery statuses and replies can be matched to what you sent.
• Honour opt-outs. When a customer asks to stop, record it and check the record before every marketing send.
• Monitor quality. Watch your number's quality rating and template status in WhatsApp Manager; a paused template silently stops a flow.
• Keep secrets out of code. Rotate tokens and keep them in a secret manager.

Meta charges per delivered template message, by category and by the recipient’s country. For Indian numbers on the October 1, 2026 rate card, before GST: marketing ₹0.8631, utility ₹0.115, authentication ₹0.115. Since 1 October 2026, free-form replies inside the 24-hour window are charged at the utility rate too; conversations a customer opens from a click-to-WhatsApp ad or Facebook Page button stay free for 72 hours.

So an order-confirmation service sending 10,000 utility messages a month to Indian customers costs about ₹1,150 in Meta charges. Model your own volumes with the WhatsApp API cost calculator.

Many searches for "WhatsApp API send message" are really about click-to-chat links. A link like https://wa.me/919876543210?text=Hi (or the older https://api.whatsapp.com/send?phone=919876543210&text=Hi) opens WhatsApp on the user’s device with a chat to that number and the text pre-filled. The user still presses send — nothing is sent automatically, and no business account is needed.

Click-to-chat links are perfect for "Chat with us" buttons, QR codes and email signatures. Make one in seconds with the WhatsApp link generator, or a floating website button with the WhatsApp chat button generator. For messages your system sends on its own, you need the Cloud API described above.

Calling the Cloud API directly is the right choice when WhatsApp is one channel inside a product you already build: transactional messages from your backend, OTPs, alerts. You control everything, and you only pay Meta’s message charges.

It becomes a bigger project once people outside engineering need WhatsApp too: marketing wants to send campaigns to segments, support needs a shared inbox, sales wants an AI agent that answers and books. Each of those is an interface someone has to build and maintain. That is what platforms such as Reputoo provide on top of the same Cloud API — campaigns, a team inbox, automations and AI agents — while store events from Shopify, WooCommerce or Zapier trigger messages without code.

Many teams do both: their backend sends transactional messages directly, and the marketing and support side runs on a platform. Our Cloud API explainer covers the trade-offs in more detail.