Skill v1.0.0

version: "1.0.0" name: twilio-whatsapp-send-message description: > WhatsApp messaging deep-dive reference. Covers the 24-hour service window rules (free-form vs template mode), sandbox setup for testing, template approval workflow, production sender requirements, and WhatsApp-specific error handling. For sending WhatsApp messages, use twilio-send-message instead. Use this skill when setting up WhatsApp for the first time or debugging WhatsApp-specific delivery behavior.

Overview

WhatsApp is one channel in Twilio's Messaging platform. All channels share the same messages.create() API — see twilio-messaging-overview for the full channel comparison and onboarding sequence.

Twilio routes WhatsApp through the Programmable Messaging API — all numbers use whatsapp:+E.164 prefix. Two sending modes apply: free-form (within 24 hrs of last inbound) and template (anytime). Sending free-form outside the window causes silent delivery failure — always check which mode is required.

Prerequisites

• Twilio account with WhatsApp enabled

— New to Twilio? See twilio-account-setup

• Environment variables:
• TWILIO_ACCOUNT_SID
• TWILIO_AUTH_TOKEN

— See twilio-iam-auth-setup for credential setup and best practices

• SDK: pip install twilio / npm install twilio
• Recipient opted in to receive messages from your WhatsApp Business Account

Testing (sandbox): Join by texting join <your-code> to +14155238886. No registration needed — see Console > Messaging > Try it out > Send a WhatsApp message. Sandbox participants must re-join every 3 days.

Production: Register a WhatsApp Business sender first — see twilio-whatsapp-manage-senders.

Quickstart

Python

import os
from twilio.rest import Client
client = Client(os.environ["TWILIO_ACCOUNT_SID"], os.environ["TWILIO_AUTH_TOKEN"])
message = client.messages.create(
    from_="whatsapp:+14155238886",   # Sandbox sender (or your production number)
    to="whatsapp:+15005550006",      # Must have joined the sandbox
    body="Your order has been confirmed."
)
print(message.sid)     # MMxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
print(message.status)  # queued | sent | delivered | failed

Node.js

const twilio = require("twilio");
const client = twilio(process.env.TWILIO_ACCOUNT_SID, process.env.TWILIO_AUTH_TOKEN);
 
const message = await client.messages.create({
    from: "whatsapp:+14155238886",
    to: "whatsapp:+15005550006",
    body: "Your order has been confirmed.",
});
 
console.log(message.sid);
console.log(message.status);

Key Patterns

Send a Template Message (outside service window)

Templates are created in Console > Messaging > Content Template Builder and must be approved by Meta. See twilio-content-template-builder for template creation.

Python

message = client.messages.create(
    from_="whatsapp:+14155238886",
    to="whatsapp:+15005550006",
    content_sid="HXxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
    content_variables='{"1": "March 25", "2": "2:00 PM"}'
)

Node.js

const message = await client.messages.create({
    from: "whatsapp:+14155238886",
    to: "whatsapp:+15005550006",
    contentSid: "HXxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
    contentVariables: JSON.stringify({ "1": "March 25", "2": "2:00 PM" }),
});

Send Media (free-form only)

Max file size: 16 MB.

Python

message = client.messages.create(
    from_="whatsapp:+14155238886",
    to="whatsapp:+15005550006",
    body="Here is your invoice.",
    media_url=["https://example.com/invoice.pdf"]
)

Node.js

const message = await client.messages.create({
    from: "whatsapp:+14155238886",
    to: "whatsapp:+15005550006",
    body: "Here is your invoice.",
    mediaUrl: ["https://example.com/invoice.pdf"],
});

Response Fields

Common Errors

CANNOT

• Cannot exceed 80 messages/second per sender — Text-only can be raised to 400 MPS on request
• Cannot queue messages beyond 4 hours — Undelivered messages fail after 4 hours
• Cannot exceed sandbox throttle limits — 1 message per 3 seconds, 50 messages/day on trial, participants expire after 3 days
• Cannot send without opt-in — Sending without recipient opt-in risks account suspension
• Cannot use WhatsApp Groups API — Deprecated April 2020. Use Conversations API instead.

Next Steps

• Channel overview and onboarding guide: twilio-messaging-overview
• Register a production WhatsApp sender: twilio-whatsapp-manage-senders
• Create and manage message templates: twilio-content-template-builder
• Multi-channel conversations with history: twilio-conversations-api