Send messages

POST to Meta Graph API v24.0 with a Bearer token. Same shape for the sandbox through the proxy and your own number direct.

The basic call

Every send is a POST to ${WHATSAPP_API_URL}/${WHATSAPP_PHONE_NUMBER_ID}/messages with Authorization: Bearer ${WHATSAPP_ACCESS_TOKEN} and a JSON body whose first key is messaging_product: "whatsapp".

The shape is identical for the sandbox (through the HookMyApp proxy) and your own number (direct to Meta). Only the base-URL variable differs: the sandbox env sets WHATSAPP_API_URL, while your own number's env sets META_GRAPH_API_URL. The Node example below reads whichever is present (WHATSAPP_API_URL ?? META_GRAPH_API_URL); the curl example uses whichever your env has. For the full message-object reference see Meta's Cloud API docs.

curl example

curl -X POST "${WHATSAPP_API_URL}/${WHATSAPP_PHONE_NUMBER_ID}/messages" \
  -H "Authorization: Bearer ${WHATSAPP_ACCESS_TOKEN}" \
  -H "Content-Type: application/json" \
  -d '{
    "messaging_product": "whatsapp",
    "to": "+15551234567",
    "type": "text",
    "text": { "body": "Hello from my app" }
  }'

Node/Express example

Verbatim from the webhook starter kit (src/providers/whatsapp.js). It reads whichever base-URL variable your env has, so the same code runs against the sandbox and your own number.

export async function send(to, text) {
  const base = process.env.WHATSAPP_API_URL ?? process.env.META_GRAPH_API_URL;
  const url = `${base}/${process.env.WHATSAPP_PHONE_NUMBER_ID}/messages`;
  const res = await fetch(url, {
    method: 'POST',
    headers: {
      Authorization: `Bearer ${process.env.WHATSAPP_ACCESS_TOKEN}`,
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({ messaging_product: 'whatsapp', to, type: 'text', text: { body: text } }),
  });
  if (!res.ok) {
    const err = await res.json().catch(() => ({}));
    throw new Error(`WhatsApp API error ${res.status}: ${JSON.stringify(err)}`);
  }
  return res.json();
}

Templates need your own number

Sandbox blocks template sends.

The sandbox proxy rejects type: "template" messages. Test templates against a connected WhatsApp number, not the sandbox.

Rate limits and retries

Meta enforces per-phone messaging tiers and per-account business-initiated-conversation quotas. HookMyApp passes rate-limit error responses through untouched so your retry logic sees them directly.

For current tier thresholds, pair rates, and the 429 retry contract, see Meta's rate-limit docs.

Next steps

• Receive Webhooks: Handle the delivery and read receipts.
• Sandbox: Try the send flow end-to-end with a test number.