When does the session window close?

If the client has not written or replied within 24 hours, sendMessage will fail until a template reopens the chat.

How do I check delivery?

sent: true only confirms acceptance. Track delivery via webhook hooks[] or polling.

What if the message is not delivered?

Log the failed/undelivered hook, verify the session window, then retry or use a template.

Can I connect this to my CRM or backend?

Yes — trigger the API call from your inbound webhook or workflow engine.

WhatsApp Business API for product catalog — interactive list

This scenario sends an interactive list with sendList during the 24-hour session window.

Try the demo View code example

Use case overview

This scenario sends an interactive list with sendList during the 24-hour session window. Two sections group product rows; the client opens the catalog and selects an item.

Template example

Browse our catalog for {{1}}:

{{1}}
campaign or product context shown in the list header text

WhatsApp Business API for product catalog — interactive list

When to use it

Reach for this scenario when a WhatsApp sales campaign already has an open session and the buyer needs to pick a SKU without an agent pasting long product lists. It fits teams running promotional sends where a structured catalog beats free-text and manual SKU entry would slow checkout.

Less buyer drop-off mid-chat

sendList replaces pasted SKU walls with two grouped sections and a View catalog button, so the buyer selects inside WhatsApp instead of abandoning a hard-to-scan text list on mobile.

No manual sku entry

The client taps a product row in the interactive list and your inbound webhook receives the row id, so agents and backends skip retyping SKUs from chat.

Campaign context in one variable

One body variable carries the campaign or promo label in the list header text, so the same list layout works across offers without rewriting the message body.

Checkout continues from the selection

The webhook passes the product row id to your CRM or storefront, which continues the order or follow-up flow from that SKU instead of asking the buyer to repeat their choice.

Workflow

Customer acts
A campaign event or client reply keeps the session open.
user action
Capture event
Your backend builds a two-section interactive list with product rows.
POST /send_list
Taps View catalog
The client taps View catalog and selects a product.
user action
Delivered
The webhook returns the row id for order or CRM processing.
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
TEST_PRODUCTCONTEXT="___"         # {{1}} product context

PHONE_NORM="$(printf '%s' "$TEST_PHONE" | tr -cd '0-9')"
URL="${API_BASE_URL%/}/${CHANNEL_ID}/sendList"

read -r -d '' PAYLOAD <<JSON || true
{
  "phone": "${PHONE_NORM}",
  "body": "Browse our catalog for spring promotion:",
  "buttonText": "View catalog",
  "action": "catalog",
  "sections": [{"title":"Featured products","rows":[{"id":"prod_alpha","title":"Alpha Widget","description":"Compact model"},{"id":"prod_beta","title":"Beta Widget","description":"Standard model"}]},{"title":"Bundles","rows":[{"id":"bundle_starter","title":"Starter pack","description":"Two items included"},{"id":"bundle_pro","title":"Pro pack","description":"Four items included"}]}]
}
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 ] && [ "$ok" -eq 1 ]; then
  echo "Message sent to client."
else
  echo "$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,
  "id": "wamid.HBgLMzgwNjM5...",
  "message": "Message accepted for delivery"
}

sent
Accepted for sending — not yet on the customer's phone
id
Store it; delivery callbacks and hookInfo are 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.

200 OKDelivery status webhook — payload you receive

{
  "hooks": [
    {
      "id": "gBGGeSaGViBfAgnlzOSHEwK9O6F",
      "type": "message",
      "status": "sent",
      "timestamp": "1654864094",
      "recipient_id": "556123122026"
    }
  ]
}

status
sent, delivered, read — or a failure status when applicable
id
Correlates the callback with the id returned by the send call
timestamp
Unix 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.