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Delivery delay notification via WhatsApp API

The scenario sends the customer a personalized WhatsApp template when their order delivery is delayed.

Use case overview

The scenario sends the customer a personalized WhatsApp template when their order delivery is delayed. The message includes the customer name, order number, product name, and revised ETA or delay reason. A static URL button opens shipment tracking.

Template example

Hello, {{1}}! Unfortunately, delivery of order #{{2}} for "{{3}}" is delayed. {{4}}.

Track shipment
  • {{1}}
    customer name
  • {{2}}
    order number
  • {{3}}
    product name
  • {{4}}
    revised ETA or delay reason
  • “Track shipment”
    button — fixed in the Meta template
WhatsApp Business API for delivery delay notification

When to use it

Reach for this scenario when a carrier or warehouse reports a slip on the promised delivery date and the customer may have no open WhatsApp thread — only an approved template can reach them first. It fits e-commerce logistics teams, marketplaces fielding WISMO tickets after carrier delays, and integrators wiring TMS delay webhooks into WhatsApp outbound.

Fewer inbound WISMO tickets
Order number, product name and revised ETA or delay reason arrive as four body variables in the customer's chat, so they learn about the slip in WhatsApp before opening a support ticket.
Trust when ETA slips
Logistics fires the template on the delay event while the customer still has no open conversation, so an approved template reaches them outside the 24-hour window instead of waiting for them to call.
No manual delay outreach
The TMS or OMS delay event triggers the send automatically, so no agent retypes order details or hunts for the customer's phone.
Tracking without a support call
The static URL button fixed in the Meta template opens shipment tracking, so the customer can follow the parcel from the same message that explains the delay.
Delivery logged for CRM follow-up
Delivery result is written back after send, so support sees the delay notice on the order record without a separate note.

Workflow

  1. Trigger

    Logistics marks a delivery delay and fires an event.

    event · triggered

  2. Capture event

    The system resolves the customer phone number and delay 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 open tracking via the button.

    delivered

  5. Status tracked

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

    status: "read"

WhatsApp Business API for delivery delay 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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