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Welcome message after signup via WhatsApp API

The scenario sends a personalised WhatsApp template when a user completes registration.

Use case overview

The scenario sends a personalised WhatsApp template when a user completes registration. The message includes the customer's name and the service or app they signed up for. A static URL button opens the account or getting-started page.

Template example

Welcome {{1}}! Thank you for registering with {{2}}. We are excited to have you on board. Tap the button below to open your account and complete your first steps. If you need help getting started, feel free to reply to this message.

Open Account
  • {{1}}
    customer name
  • {{2}}
    service or app name the user registered for
  • “Open Account”
    button — fixed in the Meta template
WhatsApp Business API for registration welcome message

When to use it

Use this scenario when a user finishes registration with a phone number on file and the business needs a warm welcome to land immediately — before they drift away from onboarding. It fits SaaS and mobile apps greeting new sign-ups, portals and marketplaces nudging profile completion, and agencies wiring client registration webhooks to automated WhatsApp onboarding.

Welcome while sign-up intent is fresh
The app emits a registration-completed event with the phone collected during sign-up, and an approved template reaches the new user on WhatsApp even though no conversation is open yet.
Greeting that names them and their app
Two body variables carry the customer name and the service or app they registered for, so the welcome reads as personal confirmation instead of a generic broadcast.
One tap into the account
A static URL button fixed in the Meta template opens the account or getting-started page, so the user has a direct path without waiting inside the 24-hour reply window.
No manual welcome work
The system pulls name and service context from the registration payload and sends the template automatically, so no one retypes details or remembers to message each new user.
Onboarding delivery tracking
Delivery result is logged for onboarding analytics or support follow-up, so the team knows whether the welcome landed before chasing the user elsewhere.

Workflow

  1. Capture event

    The app or portal emits a registration-completed event with the user's phone number.

    phone: "+…"

  2. Retrieves the customer name

    The system retrieves the customer name and service or app context from the registration payload.

    phone: "+…"

  3. Build & send

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

    POST /sendTemplate

  4. Delivered

    The new user receives the WhatsApp welcome message and can open their account via the button.

    delivered

  5. Status tracked

    Delivery result is logged for onboarding analytics or support follow-up.

    status: "read"

WhatsApp Business API for registration welcome message

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

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"; 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 → ${TEST_SERVICE}
read -r -d '' PAYLOAD <<JSON || true
{
  "phone": "${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}" }
      ]
    }

  ]
}
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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