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Back-in-stock notification via WhatsApp API

The scenario sends the customer a personalized WhatsApp template when ordered or reserved stock arrives at the warehouse.

Use case overview

The scenario sends the customer a personalized WhatsApp template when ordered or reserved stock arrives at the warehouse. The message includes the customer name, order or reference number, product name, and fulfilment next step. A static URL button opens order confirmation or tracking.

Template example

Hello, {{1}}! For order #{{2}}, item "{{3}}" is now in stock. {{4}}.

Confirm shipment
  • {{1}}
    customer name
  • {{2}}
    order or reference number
  • {{3}}
    product name
  • {{4}}
    fulfilment next step or availability note
  • “Confirm shipment”
    button — fixed in the Meta template
WhatsApp Business API for stock arrival notification

When to use it

Use this scenario when a customer is waiting on a pre-order or paused order and stock finally arrives at the warehouse — and they need to hear about it even though there is no open WhatsApp chat. It fits back-in-stock fulfilment teams, e-commerce operators resuming orders after supplier delivery, and integrators connecting WMS stock-in webhooks to outbound WhatsApp.

Faster fulfilment restart
When the WMS registers stock for the relevant SKU, the template goes out with customer name, order reference, product name and next-step note in four body variables, and the Confirm shipment URL button lets them resume without checking a portal.
Fewer "is it in stock yet?" support tickets
Order number and product name land in the customer's WhatsApp chat together with the availability note, so they stop polling support or refreshing an order page.
No manual back-in-stock outreach
The stock-arrival event from the warehouse system builds and sends the template automatically — no one retypes order details or remembers to notify each waiting customer.
Compliant reach without an open conversation
Because the customer may have no active session, the approved utility template is the allowed first message; only the four body variables are sent via the API while the order URL stays fixed in Meta.

Workflow

  1. Trigger

    The WMS registers stock arrival for the relevant SKU and fires an event.

    event · triggered

  2. Capture event

    The system resolves the customer phone number and order or product fields.

    phone: "+…"

  3. Build & send

    A personalized template message is built with four body variables and a static URL button.

    POST /sendTemplate

  4. Delivered

    The customer receives the WhatsApp update and can confirm fulfilment via the button.

    delivered

  5. Status tracked

    Delivery result is logged; errors are handled according to platform rules.

    status: "read"

WhatsApp Business API for stock arrival notification

Technical implementation

Prerequisites

  1. 1MSG API Key · How to get API Key
  2. WhatsApp Business account · How to Connect WABA
  3. WhatsApp Template · How to Approve WABA Template
  4. 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_TICKETNUMBER="___"         # {{2}} ticket number
TEST_PRODUCTNAME="___"         # {{3}} product name
TEST_NEXTSTEP="___"         # {{4}} next step

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=$TEST_CUSTOMERNAME" \
            "TEST_TICKETNUMBER=$TEST_TICKETNUMBER" \
            "TEST_PRODUCTNAME=$TEST_PRODUCTNAME" \
            "TEST_NEXTSTEP=$TEST_NEXTSTEP"; 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}} ticket number → ${TEST_TICKETNUMBER}
# {{3}} product name → ${TEST_PRODUCTNAME}
# {{4}} next step → ${TEST_NEXTSTEP}
read -r -d '' PAYLOAD <<JSON || true
{
  "phone": "${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": "${TEST_TICKETNUMBER}" },
        { "type": "text", "text": "${TEST_PRODUCTNAME}" },
        { "type": "text", "text": "${TEST_NEXTSTEP}" }
      ]
    }

  ]
}
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

StatusAPI responseCauseFix
200Message was not sent: template is not definednamespace, 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"}.
200template 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.
200Message was not sent: provide chatId, phone, bsuid, or usernameNo recipient the channel could resolve.Pass exactly one recipient: phone (country code plus number, digits only), chatId (for example [email protected]) or bsuid.

All error codes →

Common questions

Related

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