Offline payment receipt via WhatsApp API

The scenario sends the customer a personalised WhatsApp template when an offline payment is recorded.

Use case overview

The scenario sends the customer a personalised WhatsApp template when an offline payment is recorded. The message includes the customer name, payment amount, and payment date. A static URL button opens the receipt or payment history page.

Template example

Hello, {{1}}! We recorded your offline payment of {{2}} on {{3}}. Thank you.

View receipt

{{1}}
customer name
{{2}}
payment amount
{{3}}
payment date
“View receipt”
button — fixed in the Meta template

WhatsApp Business API for offline payment notification

When to use it

Reach for this scenario when staff or billing posts a cash, transfer, or in-person payment and the customer needs proof right away but has no open WhatsApp chat — only an approved template can go out first. It fits retail and field teams logging counter payments, finance teams matching bank transfers to accounts, and integrators wiring ERP or POS payment-posting events to customer confirmations.

Fewer "did you get my payment?" calls

Customer name, amount, and payment date arrive as three body variables the moment billing records the offline payment, so the client sees posting proof without calling support or checking email.

Proof in a channel they already use

The confirmation lands in WhatsApp where the customer already chats, so payment details stay searchable in the thread instead of buried in a receipt email.

Receipt without a support ticket

A static URL button fixed in the Meta template opens the receipt or payment history page, so the customer can pull documentation without asking staff to resend it.

No manual confirmation work

Billing or back-office fires the template when it posts the payment and resolves the customer phone, and delivery status is logged for billing or CRM follow-up.

Workflow

Trigger
Staff or billing records an offline payment and fires a confirmation event.
event · triggered
Capture event
The system resolves the customer phone number and payment fields.
phone: "+…"
Build & send
A personalised template message is built with three body variables and a static URL button.
POST /sendTemplate
Delivered
The customer receives the WhatsApp notification and can open the receipt via the button.
delivered
Status tracked
Delivery result is logged for billing or CRM follow-up.
status: "read"

Technical implementation

Prerequisites

1MSG API Key · How to get API Key
WhatsApp Business account · How to Connect WABA
WhatsApp Template · How to Approve WABA Template
Customer opt-in · How to Manage Customers Consent

Code examples

#!/usr/bin/env bash
set -euo pipefail

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

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

TEMPLATE_NAME="___"                        # approved template name
TEMPLATE_NAMESPACE="___"                   # template namespace (required — send fails without it)
TEMPLATE_LANGUAGE="___"                    # template language code, e.g. "en"



# === Test data ===
TEST_PHONE="___"                 # client phone in international format
TEST_CUSTOMERNAME="___"         # {{1}} customer name
TEST_PAYMENTAMOUNT="___"         # {{2}} payment amount
TEST_DATE="___"         # {{3}} date or time

PHONE_NORM="$(printf '%s' "$TEST_PHONE" | tr -cd '0-9')"

for pair in "CHANNEL_ID=$CHANNEL_ID" "API_TOKEN=$API_TOKEN" \
            "TEMPLATE_NAME=$TEMPLATE_NAME" "TEMPLATE_NAMESPACE=$TEMPLATE_NAMESPACE" \
            "TEMPLATE_LANGUAGE=$TEMPLATE_LANGUAGE" "TEST_PHONE=$TEST_PHONE" \
            "TEST_CUSTOMERNAME=$TEST_CUSTOMERNAME" \
            "TEST_PAYMENTAMOUNT=$TEST_PAYMENTAMOUNT" \
            "TEST_DATE=$TEST_DATE"; do
    val="${pair#*=}"
    if [ -z "$val" ] || [ "$val" = "___" ]; then
        echo "Missing configuration value: ${pair%%=*}" >&2
        exit 1
    fi
done

if [ -z "$PHONE_NORM" ]; then
    echo "Error: phone number has no digits after normalization" >&2
    exit 1
fi

URL="${API_BASE_URL%/}/${CHANNEL_ID}/sendTemplate"

# params carries body ONLY. Button text is fixed in the Meta template — no button param.

# {{1}} customer name → ${TEST_CUSTOMERNAME}
# {{2}} payment amount → ${TEST_PAYMENTAMOUNT}
# {{3}} date or time → ${TEST_DATE}
read -r -d '' PAYLOAD <<JSON || true
{
  "phone": "${PHONE_NORM}",
  "template": "${TEMPLATE_NAME}",
  "namespace": "${TEMPLATE_NAMESPACE}",
  "language": { "policy": "deterministic", "code": "${TEMPLATE_LANGUAGE}" },
  "params": [
    {
      "type": "body",
      "parameters": [
        { "type": "text", "text": "${TEST_CUSTOMERNAME}" },
        { "type": "text", "text": "${TEST_PAYMENTAMOUNT}" },
        { "type": "text", "text": "${TEST_DATE}" }
      ]
    }

  ]
}
JSON

RESPONSE="$(curl -s -w '\n%{http_code}' -X POST "$URL" \
    -H "Content-Type: application/json" \
    -H "Authorization: Bearer ${API_TOKEN}" \
    -d "$PAYLOAD")"

HTTP_CODE="$(printf '%s' "$RESPONSE" | tail -n1)"
BODY="$(printf '%s' "$RESPONSE" | sed '$d')"

case "$BODY" in
    *'"sent":true'*) ok=1 ;;
    *) ok=0 ;;
esac

if [ "$HTTP_CODE" -ge 200 ] && [ "$HTTP_CODE" -lt 300 ] && [ "$ok" -eq 1 ]; then
    echo "Message sent to client."
    echo "API response: $BODY"
else
    echo "Send failed. HTTP status: $HTTP_CODE" >&2
    echo "$BODY" >&2
    exit 1
fi

Response and delivery status

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 (looks like wamid.…) to correlate delivery callbacks.

200 OKResponse

{
  "sent": true,
  "message": "Sent to [email protected]",
  "description": "Message has been sent to the provider",
  "id": "wamid.HBgLMzgwNjM5..."
}

sent
Accepted for sending — not yet on the customer's phone
id
Store it; delivery callbacks and hookInfo are keyed on this

Delivery statuses and webhooks →

Common errors

Status	API response	Cause	Fix
200	Message was not sent: template is not defined	namespace, template or language is missing from the request body.	Send all three. Take namespace and the exact template name from GET /templates; language is an object: {"policy": "deterministic", "code": "en"}.
200	template name (…) does not exist in <language>	The template is approved in a different language than the one requested.	Use the exact language code the template was approved in (for example es_MX is not the same as es). Check it in GET /templates.
200	Message was not sent: provide chatId, phone, bsuid, or username	No recipient the channel could resolve.	Pass exactly one recipient: phone (country code plus number, digits only), chatId (for example [email protected]) or bsuid.