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Same-day appointment reminder via WhatsApp API

The scenario sends the client a personalised WhatsApp template on the day of the visit.

Use case overview

The scenario sends the client a personalised WhatsApp template on the day of the visit. The message includes the client name, service name, visit time, and address. A static URL button opens booking details.

Template example

Hello, {{1}}! Today you have {{2}} at {{3}}. Address: {{4}}. See you soon!

View booking
  • {{1}}
    customer name
  • {{2}}
    service or appointment type
  • {{3}}
    visit time
  • {{4}}
    visit address or location
  • “View booking”
    button — fixed in the Meta template
WhatsApp Business API for same-day visit reminder

When to use it

Use this scenario when a client has a visit scheduled for today and you need time and address to reach them before they leave — especially where a missed slot costs a paid hour. It fits clinics and home-visit teams, salons juggling back-to-back appointments on busy days, and integrators who run a morning batch from the calendar to WhatsApp.

Fewer no-shows
Name, service, visit time and address arrive as four body variables in the client's WhatsApp chat on the day of the visit, so the details stay searchable there instead of buried in email they never open.
Fewer late arrivals on busy days
The scheduling system fires the reminder when it identifies visits due today, so clients get time and location in WhatsApp while they are still planning their day.
No manual reminder work
A morning batch or same-day trigger from the calendar sends the approved template automatically — no staff retypes visit details for each appointment.
Booking details one tap away
The static URL button opens the booking page fixed in the Meta template, for anything the four body variables do not cover.

Workflow

  1. Trigger

    The scheduling system identifies visits due today and fires a reminder event.

    event · triggered

  2. Capture event

    The system resolves the client phone number and visit fields.

    phone: "+…"

  3. Build & send

    A personalised template message is built with four body variables and a static URL button.

    POST /sendTemplate

  4. Delivered

    The client receives the same-day WhatsApp reminder.

    delivered

  5. Status tracked

    Delivery result is logged for scheduling or CRM follow-up.

    status: "read"

WhatsApp Business API for same-day visit reminder

Technical implementation

Prerequisites

  1. 1MSG API Key · How to get API Key
  2. WhatsApp Business account · How to Connect WABA
  3. WhatsApp Template · How to Approve WABA Template
  4. 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_SERVICE="___"         # {{2}} service name
TEST_BOOKINGTIME="___"         # {{3}} booking time
TEST_ADDRESS="___"         # {{4}} address or location

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_BOOKINGTIME=$TEST_BOOKINGTIME" \
            "TEST_ADDRESS=$TEST_ADDRESS"; 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 time → ${TEST_BOOKINGTIME}
# {{4}} address or location → ${TEST_ADDRESS}
read -r -d '' PAYLOAD <<JSON || true
{
  "phone": "${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_BOOKINGTIME}" },
        { "type": "text", "text": "${TEST_ADDRESS}" }
      ]
    }

  ]
}
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

StatusAPI responseCauseFix
200Message was not sent: template is not definednamespace, 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"}.
200template 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.
200Message was not sent: provide chatId, phone, bsuid, or usernameNo recipient the channel could resolve.Pass exactly one recipient: phone (country code plus number, digits only), chatId (for example [email protected]) or bsuid.

All error codes →

Common questions

Related

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