Send a WhatsApp message with Node.js

// Node.js 18+ (built-in fetch). Save as send.mjs so top-level await works.
// Run on your server — never ship the key to a browser.
const BASE_URL = "https://public.leadpattern.com";
const API_KEY = process.env.LEADPATTERN_API_KEY; // YOUR_API_KEY

const headers = {
  Authorization: API_KEY, // the raw key, NO "Bearer " prefix
  "Content-Type": "application/json",
};

// Return data on 201, otherwise throw with the status, body and Retry-After
class LeadPatternError extends Error {
  constructor(status, body, retryAfter) {
    super(`HTTP ${status}: ${JSON.stringify(body)}`);
    Object.assign(this, { status, body, retryAfter });
  }
}

async function handle(res) {
  const body = await res.json().catch(() => null);
  if (res.status === 201) return body.data; // { messageId } or { messages: [...] }
  // e.g. { type: "error", code: 403, message: "..." }
  throw new LeadPatternError(res.status, body, Number(res.headers.get("Retry-After")) || 60);
}

// Optional: check connectivity (public endpoint, no key needed)
const health = await fetch(`${BASE_URL}/health-check`);
console.log(health.status);

async function sendTemplate(to, templateName, language, placeholders) {
  // placeholders = [{ name: "..." }, { order_id: "..." }]
  const res = await fetch(`${BASE_URL}/v2/whatsapp/message/template`, {
    method: "POST",
    headers,
    body: JSON.stringify({
      messages: [
        {
          to, // E.164 with country code, e.g. "+91XXXXXXXXXX"
          content: {
            templateName,
            language,
            templateData: { body: { placeholders } },
          },
        },
      ],
    }),
  });
  return handle(res);
}

const data = await sendTemplate("+91XXXXXXXXXX", "order_confirmation", "en", [
  { name: "Customer" },
  { order_id: "ORD-1234" },
]);
console.log(data.messages[0].messageId);

{
  "type": "success",
  "data": {
    "messages": [
      {
        "status": "SENT",
        "recipient": "91XXXXXXXXXX",
        "messageId": "wamid.abc123"
      }
    ]
  }
}

// Free-form text — only works within 24 hours of the customer's last message.
async function sendText(to, text, previewUrl = false) {
  const res = await fetch(`${BASE_URL}/whatsapp/message/text`, {
    method: "POST",
    headers,
    body: JSON.stringify({ to, content: { text, previewUrl } }),
  });
  return handle(res);
}

console.log((await sendText("+91XXXXXXXXXX", "Hello! How can I help you?")).messageId);

{
  "type": "success",
  "data": {
    "messageId": "wamid.abc123",
    "status": "sent",
    "recipient": "91XXXXXXXXXX"
  }
}

const sleep = (s) => new Promise((r) => setTimeout(r, s * 1000));

try {
  await sendText("+91XXXXXXXXXX", "Your order has shipped.");
} catch (e) {
  if (e.status === 429) {
    await sleep(e.retryAfter); // wait for Retry-After, then retry once
    await sendText("+91XXXXXXXXXX", "Your order has shipped.");
  } else if (e.status === 403) {
    // 24-hour window closed (or IP / plan restriction) -> send a template instead
    await sendTemplate("+91XXXXXXXXXX", "order_confirmation", "en", [
      { name: "Customer" },
      { order_id: "ORD-1234" },
    ]);
  } else {
    throw e;
  }
}

{
  "type": "error",
  "code": 403,
  "message": "Cannot send a free-form message. The 24-hour customer service window has expired. You may only send template messages after 24 hours of the last user message."
}