No-reply follow-up message via WhatsApp API

The scenario sends the client a personalised WhatsApp template when they did not reply to a prior service message within the expected time.

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Use case overview

The scenario sends the client a personalised WhatsApp template when they did not reply to a prior service message within the expected time. The message includes the client name, the topic or context of the original request, and a reminder of what response is still needed. A static URL button opens the portal or reply page.

Template example

Hello, {{1}}! We sent you a message about "{{2}}", but have not received a reply yet. {{3}} Please respond when convenient — we are here to help.

{{1}}
customer name
{{2}}
topic or subject of the prior message (e.g. appointment confirmation, feedback survey, document request)
{{3}}
reminder detail (e.g. please confirm by Friday, reply with your preferred time)
“Reply”
button — fixed in the Meta template

WhatsApp Business API for follow-up when no response received

When to use it

Reach for this scenario when a client was asked to confirm, upload, or respond on WhatsApp and the expected window passed with no reply — and the process cannot advance until they act. It fits onboarding and form reminders, service workflows waiting on confirmation or documents, and agencies wiring no-response timers from CRM or BPM into WhatsApp outbound.

Stalled processes move again without phone calls

When the no-response timeout elapses, CRM or workflow triggers the follow-up template so the client gets a clear nudge in WhatsApp instead of a rep chasing by phone.

Outreach stays compliant when the chat is closed

There is no open conversation after the first message, so only an approved template can reach the client — the scenario sends that template via the 1MSG API when the timer fires.

Reminders that name the original request

Three body variables carry the client name, the topic of the prior message, and what response is still needed, so the follow-up reads as a continuation of the same thread.

A direct path to reply

A static URL button fixed in the Meta template opens the portal or reply page; only the body variables are sent via the API.

Delivery logged for CRM follow-up

Delivery result is logged after send, so CRM or back office can track who was nudged and handle errors according to platform rules.

Workflow

Trigger
The CRM or workflow detects that the no-response timeout has elapsed.
event · triggered
Capture event
The system resolves the recipient phone number and follow-up fields.
phone: "+…"
Build & send
A personalised template message is built with three body variables and a static URL button.
POST /sendTemplate
Delivered
The client receives the WhatsApp follow-up reminder.
delivered
Status tracked
Delivery result is logged; errors are handled according to platform rules.
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_TOPIC="___"         # {{2}} topic or subject
TEST_REQUESTDETAIL="___"         # {{3}} request detail

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=$TEST_CUSTOMERNAME" \
            "TEST_TOPIC=$TEST_TOPIC" \
            "TEST_REQUESTDETAIL=$TEST_REQUESTDETAIL"; do
    val="${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}} topic or subject → ${TEST_TOPIC}
# {{3}} request detail → ${TEST_REQUESTDETAIL}
read -r -d '' PAYLOAD <<JSON || true
{
  "phone": "${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": "${TEST_TOPIC}" },
        { "type": "text", "text": "${TEST_REQUESTDETAIL}" }
      ]
    }

  ]
}
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.