Incomplete action reminder: WhatsApp API template

The scenario sends the client a personalized WhatsApp template when they started but did not finish an important action.

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Use case overview

The scenario sends the client a personalized WhatsApp template when they started but did not finish an important action. The message includes the client name, the incomplete action, and what remains to complete. A static URL button opens the portal, checkout, or form to resume.

Template example

Hello, {{1}}! To complete {{2}}, one step remains. {{3}} If you have questions — we are here to help.

Continue

{{1}}
customer name
{{2}}
incomplete action (e.g. order payment, loan application, KYC upload)
{{3}}
remaining step or deadline (e.g. complete payment within 24 hours)
“Continue”
button — fixed in the Meta template

WhatsApp Business API for incomplete action reminder

When to use it

Reach for this scenario when a client starts checkout, onboarding, or verification but leaves before finishing — and you need them back on the exact step they abandoned. It fits e-commerce teams recovering unpaid carts, product teams nudging KYC or profile completion, and agencies wiring cart-abandon or draft-saved triggers from a client's CRM or analytics stack.

Lower drop-off on half-finished flows

Three body variables carry the client's name, the incomplete action label, and the remaining step, so the reminder names what they left behind instead of a generic nudge.

One tap back to checkout or the form

A static URL button labeled Continue opens the portal, checkout, or form where they stopped — the link is fixed in the approved Meta template while only the body text is sent via the API.

Reminders without an open chat window

Because there is no active conversation, the send uses an approved WhatsApp template via the 1MSG API — the only channel that can reach the client outside the 24-hour session window.

No manual chase after abandon events

When the system detects an incomplete state — cart timeout, draft saved, or verification stalled — it resolves the phone number and fires the template on that trigger instead of someone copying details by hand.

Delivery logged for CRM follow-up

Delivery result is logged after send, so CRM or back office can see who was reminded and handle errors according to platform rules.

Workflow

Customer acts
The client starts an action but leaves before completion.
user action
Capture event
The system detects the incomplete state and resolves the recipient phone number.
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 reminder with action context and the remaining 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_INCOMPLETEACTION="___"         # {{2}} incomplete action
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=$TEST_CUSTOMERNAME" \
            "TEST_INCOMPLETEACTION=$TEST_INCOMPLETEACTION" \
            "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}} incomplete action → ${TEST_INCOMPLETEACTION}
# {{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": "${TEST_INCOMPLETEACTION}" },
        { "type": "text", "text": "${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.