Registration OTP via WhatsApp API (copy code)

Sends a WhatsApp authentication template with a one-time registration code in the body and a copy-code button.

Use case overview

Sends a WhatsApp authentication template with a one-time registration code in the body and a copy-code button. The user copies the code and completes signup in your app.

Template example

{{1}} is your verification code. For your security, do not share this code with anyone.

Copy code

{{1}}
one-time registration verification code (digits)
“Copy code”
button — fixed in the Meta template

WhatsApp Business API for registration otp

When to use it

Reach for this when registration hits the phone-verification step and you need a one-time code delivered on cold start before any WhatsApp conversation exists. It fits new account signup, onboarding flows replacing SMS OTP, and integrators wiring phone verification into backend signup APIs.

Whatsapp instead of SMS OTP

Your backend generates a one-time registration code and sends it via an approved authentication template through the 1MSG API, so verification runs on WhatsApp rather than a separate SMS channel at signup.

Cold-start compliant delivery

Only an approved authentication template can open the chat on first contact, which is the channel rule for reaching a user who has never messaged your business before.

Faster code entry

One body variable carries the digit code and a copy-code button exposes the same value, so the user pastes into your signup form instead of retyping from memory.

Fewer silent send failures

Authentication templates require the OTP in both body and copy-code button parameters; body-only payloads return `sent: false`, and this scenario wires both from the same backend value.

Workflow

Capture event
User starts registration and requests phone verification.
phone: "+…"
Generates a one-time code
Backend generates a one-time code and resolves the WhatsApp number.
phone: "+…"
Build & send
Template message is built with the code in body and copy-code button parameter.
POST /sendTemplate
Delivered
User receives WhatsApp and submits the code in your signup form.
delivered
Status tracked
Backend validates the code and completes registration.
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_CODE="___"         # {{1}} otp code

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_CODE=$TEST_CODE"; do
    val="${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 and button blocks.

# {{1}} otp code → ${TEST_CODE}
read -r -d '' PAYLOAD <<JSON || true
{
  "phone": "${PHONE_NORM}",
  "template": "${TEMPLATE_NAME}",
  "namespace": "${TEMPLATE_NAMESPACE}",
  "language": { "policy": "deterministic", "code": "${TEMPLATE_LANGUAGE}" },
  "params": [
    {
      "type": "body",
      "parameters": [
        { "type": "text", "text": "${TEST_CODE}" }
      ]
    },
    {
      "type": "button",
      "sub_type": "url",
      "index": "0",
      "parameters": [ { "type": "text", "text": "${TEST_CODE}" } ]
    }

  ]
}
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.