Stage completed notification via WhatsApp API

The scenario sends the client a personalized WhatsApp template when they complete a stage in a multi-step process.

Use case overview

The scenario sends the client a personalized WhatsApp template when they complete a stage in a multi-step process. The message includes the client name, the completed stage, and what happens next. A static URL button opens the portal or status page.

Template example

Hello, {{1}}! Stage "{{2}}" completed successfully. Moving to the next step: {{3}} If you need help — we are here.

Open portal

{{1}}
customer name
{{2}}
completed stage name (e.g. document upload, identity verification, payment)
{{3}}
next step or following stage (e.g. manager review within 2 business days)
“Open portal”
button — fixed in the Meta template

WhatsApp Business API for stage completion notification

When to use it

Reach for this scenario when a client finishes a stage in a multi-step process — onboarding, loan application, order fulfilment — and you need to confirm the milestone plus explain what happens next, but there is no open WhatsApp chat. It fits SaaS onboarding and KYC flows, B2B pipelines where a document review stage just closed, and agencies wiring stage-completed events from CRM, BPM, or a custom workflow engine.

Less drop-off in long processes

Three body variables carry the client's name, the completed stage label, and the next step, so the milestone lands in WhatsApp where they already chat instead of waiting on email they may never open.

Fewer status-check support calls

The template names the stage that passed and what follows next, so the client does not need to call support or search inbox threads to learn where they stand in the journey.

No manual progress updates

The workflow fires the template when it marks a stage complete and resolves the recipient phone, so no one retypes stage names or next-step text for each client.

Portal access from the chat

A static URL button fixed in the Meta template opens the portal or status page, while only the three body variables are sent via the API.

Workflow

Trigger
The workflow marks a stage complete and fires a stage-completed event.
event · triggered
Capture event
The system resolves the recipient phone number and stage fields.
phone: "+…"
Build & send
A personalized template message is built with three body variables and a static URL button.
POST /sendTemplate
Delivered
The client receives the WhatsApp notification with stage context and next step.
delivered
Status tracked
Delivery result is logged; errors are handled according to platform rules.
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

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_STAGE="___"         # {{2}} stage name
TEST_NEXTSTEP="___"         # {{3}} next step

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=$TEST_CUSTOMERNAME" \
            "TEST_STAGE=$TEST_STAGE" \
            "TEST_NEXTSTEP=$TEST_NEXTSTEP"; do
    val="${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}} stage name → ${TEST_STAGE}
# {{3}} next step → ${TEST_NEXTSTEP}
read -r -d '' PAYLOAD <<JSON || true
{
  "phone": "${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": "${TEST_STAGE}" },
        { "type": "text", "text": "${TEST_NEXTSTEP}" }
      ]
    }

  ]
}
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.