
Skill
twilio-whatsapp-send-message
send WhatsApp messages via Twilio
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.
SKILL.md
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.
| Mode | When allowed | Parameters |
|---|---|---|
| Free-form | Within 24 hrs of last inbound from user | body, optional mediaUrl |
| Template | Anytime | contentSid + contentVariables |
Prerequisites
- Twilio account with WhatsApp enabled
— New to Twilio? See
twilio-account-setup - Environment variables:
TWILIO_ACCOUNT_SIDTWILIO_AUTH_TOKEN— Seetwilio-iam-auth-setupfor 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
| Field | Description |
|---|---|
sid | Unique message identifier (MM...) |
status | queued, sent, delivered, read, failed, undelivered |
error_code | Populated on failure |
error_message | Human-readable error description |
date_sent | UTC timestamp |
Common Errors
| Code | Meaning | Fix |
|---|---|---|
| 63003 | Invalid WhatsApp destination number | Verify number is WhatsApp-enabled and correctly formatted |
| 63018 | Rate limit exceeded on sender | Reduce send rate; default is 80 MPS |
| 63020 | Business hasn't accepted Twilio's Meta invitation | Accept invite in Meta Business Manager |
| N/A | Free-form outside window | Switch to a template message |
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
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