WhatsApp API session message: request ticket info

This scenario sends a free-text WhatsApp message with sendMessage inside the 24-hour customer service window.

Use case overview

This scenario sends a free-text WhatsApp message with sendMessage inside the 24-hour customer service window. Use it after an inbound webhook event when you already have an open session and must request missing ticket details.

Template example

To continue resolving ticket {{1}}, please send {{2}}.

{{1}}
support ticket number
{{2}}
what you need from the client (photo, document, clarification)

WhatsApp Business API for session reply — request additional information

When to use it

Reach for this scenario when an inbound webhook shows the client already wrote in WhatsApp and your support team needs one specific photo, document, or clarification before closing the ticket. It fits helpdesk follow-ups where the 24-hour session window is open and a template would add cost and friction to an ongoing dialog.

No template spend on open tickets

sendMessage sends free-text inside the 24-hour customer service window, so you ask for missing details without paying for a template on a conversation the client already started.

Faster ticket resolution

Two body variables carry the ticket number and the exact item you are waiting for, so the client knows what to send back without opening email or repeating the issue.

Less agent back-and-forth

Your backend maps the inbound webhook to the ticket and fills both placeholders before sendMessage fires, so the agent does not retype the request in chat.

Reply stays in the same thread

The client receives the request in the open WhatsApp session and can attach the photo or document in the same chat, where your webhook picks up the inbound reply for the helpdesk.

Workflow

Status tracked
An inbound client message arrives via webhook.
status: "read"
Capture event
Your backend maps the chat to a ticket and determines the missing detail.
POST /sendMessage
Build & send
A session text message is sent referencing the ticket and the awaited item.
POST /sendMessage
Delivered
The client replies with the requested material in the same session.
delivered

Technical implementation

Prerequisites

1MSG API Key · How to get API Key
WhatsApp Business account · How to Connect WABA
Open 24-hour session window · How the 24-hour window works
Customer opt-in · How to Manage Customers Consent
Webhook endpoint · How to Set Up Webhooks

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)



# === Test data ===
TEST_PHONE="___"                 # client phone in international format · requires open 24-hour session window
TEST_TICKETNUMBER="___"         # {{1}} ticket number
TEST_AWAITEDITEM="___"         # {{2}} awaited item

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

for pair in "CHANNEL_ID=$CHANNEL_ID" "API_TOKEN=$API_TOKEN" "TEST_PHONE=$TEST_PHONE" \
            "TEST_TICKETNUMBER=$TEST_TICKETNUMBER" \
            "TEST_AWAITEDITEM=$TEST_AWAITEDITEM"; do
  val="${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}/sendMessage"

read -r -d '' PAYLOAD <<JSON || true
{
  "phone": "${PHONE_NORM}",
  "body": "To continue resolving ticket TKT-1024, please send a photo of the damaged item."
}
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: 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.
200	Message was not sent: empty body	The body field is missing or empty.	Send a non-empty body string. It is required for text, reply-button and list messages.
401	token is required	The request has no token.	Add your channel token as the token query parameter: https://api.1msg.io/{channelId}/{method}?token=…