WhatsApp Business API for payment method clarification

Use case overview

The scenario sends the customer a personalised WhatsApp template when billing needs to know the payment method. The message includes the customer name and amount due. Two quick-reply buttons let the customer choose card or bank transfer; the webhook delivers the choice to your backend.

Template example

Hello, {{1}}! Please choose how you will pay {{2}}:

[Card]

[Bank Transfer]

Quick-reply button labels are fixed in the Meta template — only body variables are sent via the API.

Variables and purpose

• {{1}} — customer name
• {{2}} — payment amount

Filled-in example

Hello, Alex! Please choose how you will pay 150.00 USD:

[Card]

[Bank Transfer]

When to use it

• billing and checkout
• b2b invoicing
• integrators

Business value

• Billing detects that payment method is missing for an invoice or checkout
• Template is sent with customer name and payment amount
• Customer taps card or bank transfer on the quick-reply buttons
• Webhook delivers the structured choice to billing for the next payment step

Workflow

1. Billing detects that payment method is missing and fires an event.
2. The system resolves the customer phone number and payment amount.
3. A personalised template message is built with two body variables and two quick-reply buttons.
4. The customer receives the WhatsApp message and taps card or bank transfer.
5. The webhook delivers the structured choice to billing for the next payment step.
6. Delivery progress is reported asynchronously — typically sent, then delivered (or failed/undelivered).
7. Your system receives status via webhook (hooks[]) or polls GET …/hookInfo?messageId=<id> and handles failures if needed.

Technical implementation

Prerequisites

• A 1MSG account with WhatsApp Business API connected and an approved message template with two quick-reply buttons.
• Customer phone number in international format (without + and spaces).
• Payment context: customer name and amount due.
• HTTPS webhook endpoint to receive quick-reply button events.

Code examples

#!/usr/bin/env node

// === Configuration (replace "___" placeholders) ===

const API_BASE_URL = "https://api.1msg.io"; // production 1MSG API base URL
const CHANNEL_ID = "___";                   // channel ID from 1MSG dashboard
const API_TOKEN = "___";                    // channel JWT token (Bearer)

const TEMPLATE_NAME = "___";                // approved template name
const TEMPLATE_NAMESPACE = "___";           // template namespace (422 without it)
const TEMPLATE_LANGUAGE = "___";            // template language code, e.g. "en"



// === Test data ===
const TEST_PHONE = "___";            // client phone in international format
const TEST_CUSTOMERNAME = "___";    // {{1}} customer name
const TEST_PAYMENTAMOUNT = "___";    // {{2}} payment amount

function normalizePhone(phone) {
  return String(phone).replace(/\D/g, "");
}

function assertConfigured(values) {
  for (const [key, value] of Object.entries(values)) {
    if (value === "___" || value === "" || value === undefined || value === null) {
      throw new Error(`Missing configuration value: ${key}`);
    }
  }
}

async function sendTemplateMessage({ phone, customerName, paymentAmount }) {
  assertConfigured({
    CHANNEL_ID,
    API_TOKEN,
    TEMPLATE_NAME,
    TEMPLATE_NAMESPACE,
    TEMPLATE_LANGUAGE,
    phone,
    customerName,
    paymentAmount,
  });

  const url = `${API_BASE_URL}/${CHANNEL_ID}/sendTemplate`;

  // params carries body and button blocks (dynamic buttons).
  const requestBody = {
    phone: normalizePhone(phone),
    template: TEMPLATE_NAME,
    namespace: TEMPLATE_NAMESPACE,
    language: {
      policy: "deterministic",
      code: TEMPLATE_LANGUAGE,
    },
    params: [
      {
        type: "body",
        parameters: [
          { type: "text", text: String(customerName) }, // {{1}} customer name
          { type: "text", text: String(paymentAmount) }, // {{2}} payment amount
        ],
      },
    ],
  };

  const res = await fetch(url, {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      Authorization: `Bearer ${API_TOKEN}`,
    },
    body: JSON.stringify(requestBody),
  });

  const raw = await res.text();
  let data;
  try {
    data = JSON.parse(raw);
  } catch {
    data = null;
  }

  if (!res.ok || !data || data.sent !== true) {
    console.error("Send failed. API response:");
    console.error(raw);
    process.exit(1);
  }

  console.log("Message sent to client.");
  console.log("API response:", raw);
  return data;
}

function handleIncomingMessage(message) {
  const text = (message && (message.text || message.body || "")).trim();
  // Meta quick_reply label (from template.txt) → route key (code_contract.ref) "pay_by_card"
  if (text === "Картой") {
    console.log("Reply received: pay_by_card");
    return { status: "pay_by_card" };
  }
  // Meta quick_reply label (from template.txt) → route key (code_contract.ref) "pay_by_bank"
  if (text === "Банковский перевод") {
    console.log("Reply received: pay_by_bank");
    return { status: "pay_by_bank" };
  }
  console.log("Free-text reply — handle separately.");
  return { status: "other" };
}

if (require.main === module) {
  sendTemplateMessage({
    phone: TEST_PHONE,
    customerName: TEST_CUSTOMERNAME,
    paymentAmount: TEST_PAYMENTAMOUNT,
  }).catch((err) => {
    console.error("Execution failed:", err.message);
    process.exit(1);
  });
}

module.exports = { sendTemplateMessage, handleIncomingMessage };

Immediate API response (synchronous)

• HTTP 2xx and JSON "sent": true mean 1MSG accepted the message for sending — not that it already reached the customer's phone.
• Save the `id` field from the response (value looks like wamid.…). Use it to correlate delivery callbacks or polling.
• The response may also include message and description — informational only.

Delivery status (asynchronous)

• Register a webhook (POST …/webhook) so 1MSG POSTs delivery updates to your HTTPS endpoint in a separate `hooks[]` payload (sent, delivered, read, or failed/undelivered when applicable).
• Optionally poll: GET {base}/{channel}/hookInfo?messageId=<id from sendTemplate>.
• In practice, delivery often completes within a few seconds — but that is not guaranteed by the API contract.

Common errors

• Invalid or non-normalized phone number
• Unapproved or missing template name / namespace
• No customer opt-in for WhatsApp business messages
• Template variable count mismatch (422 from API)
• Delivery failure — check status webhook and retry policy

FAQ

• Do I need an approved template? Yes — cold-start WhatsApp messages require a Meta-approved template.
• Can I customize the message text? Body variables are dynamic; fixed text and button labels are set in the Meta template.
• How do I check delivery? sent: true only confirms acceptance. Track delivery via webhook hooks[] or GET …/hookInfo?messageId=<id>.
• What if the message is not delivered? Log the failed/undelivered hook, verify opt-in and template status, then retry or fall back to another channel.
• Can I connect this to my CRM or backend? Yes — trigger the API call from your platform webhook or event handler.

Related

• Knowledge base
• Creating a template
• Sending a template
• SDK