WhatsApp Business API for session reply — request additional information
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)
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.
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.
{
"sent": true,
"id": "wamid.HBgLMzgwNjM5...",
"message": "Message accepted for delivery"
}sentAccepted for sending — not yet on the customer's phone
idStore it; delivery callbacks and
hookInfoare keyed on this
Delivery itself arrives later, as a separate callback. Register a webhook (POST …/webhook) and 1MSG POSTs status updates to your HTTPS endpoint in a top-level hooks[] payload.
{
"hooks": [
{
"id": "gBGGeSaGViBfAgnlzOSHEwK9O6F",
"type": "message",
"status": "sent",
"timestamp": "1654864094",
"recipient_id": "556123122026"
}
]
}statussent,delivered,read— or a failure status when applicableidCorrelates the callback with the
idreturned by the send calltimestampUnix seconds, as a string
If you would rather not receive callbacks, poll GET {base}/{channel}/hookInfo?messageId=<id> instead. In practice delivery often completes within seconds — but the API contract does not guarantee it, so never block a flow waiting on it.
Common errors
| Status | Response | Cause |
|---|---|---|
| 200 | Message was not sent: empty body | No body in the request. |
| 200 | Message was not sent: provide chatId, phone, bsuid, or username | No recipient the channel could resolve. |
| 200 | wrong file | The media could not be fetched or uploaded — not a reachable URL, not valid base64. |
| 403 | access denied | The token is wrong, or belongs to a different channel than the URL. |
| 200 | Message was not sent: filename | sendFile called without a filename, so the media has no extension to send. |