Send a payment link via WhatsApp API

The scenario sends the customer a personalised WhatsApp template when billing or checkout needs to collect payment.

Use case overview

The scenario sends the customer a personalised WhatsApp template when billing or checkout needs to collect payment. The message includes the customer name, payment amount, and due date. A static URL button opens the online payment page.

Template example

Hello, {{1}}! Please pay {{2}} by {{3}} using the link below.

Pay now

{{1}}
customer name
{{2}}
payment amount
{{3}}
payment due date
“Pay now”
button — fixed in the Meta template

WhatsApp Business API for payment link send

When to use it

Reach for this scenario when billing or checkout creates a payment request and the customer has no open WhatsApp conversation — only an approved template can go out first. It fits invoicing and online checkout, service and B2B teams replacing lost email payment links, and integrators connecting payment gateways or ERP billing events to WhatsApp collection.

Fewer missed payment links

Customer name, amount and due date arrive as three body variables in WhatsApp, where the client already reads messages, instead of an email or SMS they never open.

Less finance follow-up work

Billing or checkout emits the payment-link event and the system resolves the phone number plus payment fields, so no one retypes amounts or manually chases links after invoicing.

One tap to the payment page

The Pay now URL button is fixed in the approved Meta template and opens the online payment page directly from the chat — only the three body variables are sent via the API.

Visibility for billing and CRM

Delivery result is logged after the template send, so finance or CRM can see who received the link instead of guessing from email opens.

Workflow

Trigger
Billing or checkout emits a payment-link 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 message and can pay 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_DUEDATE="___"         # {{3}} due date

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_DUEDATE=$TEST_DUEDATE"; do
    val="${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}} due date → ${TEST_DUEDATE}
read -r -d '' PAYLOAD <<JSON || true
{
  "phone": "${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_DUEDATE}" }
      ]
    }

  ]
}
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.