Pending booking confirmation: WhatsApp buttons API

The scenario sends the client a personalised WhatsApp template when a booking awaits confirmation.

Use case overview

The scenario sends the client a personalised WhatsApp template when a booking awaits confirmation. Two quick-reply buttons let the client confirm or cancel the booking; the webhook routes the choice to your scheduling system.

Template example

Hello, {{1}}! Please confirm your {{2}} booking on {{3}} at {{4}}:

Confirm booking

{{1}}
customer name
{{2}}
service or appointment type
{{3}}
booking date
{{4}}
booking time
“Confirm booking”
button — fixed in the Meta template

WhatsApp Business API for pending booking confirmation

When to use it

Use this scenario when a booking is created in your scheduling system but the slot should stay tentative until the client explicitly confirms or cancels on WhatsApp. It fits online booking widgets that hold a turn until confirmation, salons and clinics that want structured confirm/cancel without phone calls, and integrators routing booking-state webhooks from quick-reply taps.

Slots released when clients decline

Two quick-reply buttons in the approved template let the client confirm or cancel in one tap, and the webhook routes that choice back to the scheduling system so an unconfirmed slot is not left blocking the calendar.

No phone-tag follow-up

The pending booking event fires the template with four body variables — customer name, service, date and time — so staff are not chasing confirmations by phone or email.

Reach clients with no open chat

There is no active WhatsApp session yet, so an approved template opens the conversation and carries the personalised booking details instead of a free-text message that Meta would block.

Structured state for integrators

Quick-reply taps arrive at your HTTPS webhook as button events, so the scheduling system or CRM can confirm or release the booking without parsing free-form replies.

Workflow

Trigger
The scheduling system creates a pending booking and fires a confirmation request event.
event · triggered
Capture event
The system resolves the client phone number and booking fields.
phone: "+…"
Build & send
A personalised template message is built with four body variables and two quick-reply buttons.
POST /sendTemplate
Delivered
The client receives the WhatsApp message and taps confirm or cancel.
delivered
Status tracked
The webhook confirms or releases the booking slot.
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
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)

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_SERVICE="___"         # {{2}} service name
TEST_BOOKINGDATE="___"         # {{3}} booking date
TEST_BOOKINGTIME="___"         # {{4}} booking time

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=$TEST_CUSTOMERNAME" \
            "TEST_SERVICE=$TEST_SERVICE" \
            "TEST_BOOKINGDATE=$TEST_BOOKINGDATE" \
            "TEST_BOOKINGTIME=$TEST_BOOKINGTIME"; 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}} service name → ${TEST_SERVICE}
# {{3}} booking date → ${TEST_BOOKINGDATE}
# {{4}} booking time → ${TEST_BOOKINGTIME}
read -r -d '' PAYLOAD <<JSON || true
{
  "phone": "${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": "${TEST_SERVICE}" },
        { "type": "text", "text": "${TEST_BOOKINGDATE}" },
        { "type": "text", "text": "${TEST_BOOKINGTIME}" }
      ]
    }

  ]
}
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.