Twilio Messaging Overview

---
name: twilio-messaging-overview
description: >
  Twilio Messaging channel overview and onboarding guide. Covers all
  channels (SMS, WhatsApp, RCS, Facebook Messenger), the unified
  Messages API, channel selection guidance, and the recommended setup
  sequence from first message to production monitoring. Start here
  before choosing a specific messaging channel.
---

## Overview

Twilio's Messaging platform sends and receives messages across multiple channels through a single API. All channels use `client.messages.create()` — only the address format changes.

| Channel | Address format | Rich media | Template required? | Reach | Skill |
|---------|---------------|------------|-------------------|-------|-------|
| **SMS/MMS** | `+15551234567` (E.164) | MMS: images/video, US/CA/AU only | No | Global (180+ countries) | `twilio-sms-send-message` |
| **WhatsApp** | `whatsapp:+15551234567` | Yes (images, docs, video, location) | Outside 24hr window: yes | 190+ countries | `twilio-whatsapp-send-message` |
| **RCS** | Same number (via Messaging Service) | Yes (rich cards, carousels, video) | No | US + expanding globally | `twilio-rcs-messaging` |
| **Facebook Messenger** | `messenger:{page-scoped-id}` | Yes | No | Global | — |

---

## Which Channel Should I Use?

| If you need to... | Use | Why |
|-------------------|-----|-----|
| Reach any phone number | SMS | Universal — works on every phone, no app needed |
| Send rich media globally | WhatsApp | Images, docs, video work worldwide (MMS is US/CA/AU only) |
| Send time-sensitive alerts (OTP, outages) | SMS | Highest open rates, no app dependency |
| Reach opted-in audience at lower cost | WhatsApp | No per-message fee in many markets |
| Run marketing campaigns across channels | Start with `twilio-marketing-promotions-advisor` | Planner skill handles channel mix, compliance, and fallback |
| Send transactional notifications | Start with `twilio-notifications-alerts-advisor` | Planner skill handles urgency-based channel routing |

**Not sure?** Use a Planner skill first — it will qualify your use case and recommend the right channel combination.

---

## Unified API

All channels share `messages.create()`. The only difference is the address format in `from` and `to`.

**Python**
```python
import os
from twilio.rest import Client

client = Client(os.environ["TWILIO_ACCOUNT_SID"], os.environ["TWILIO_AUTH_TOKEN"])

# SMS
sms = client.messages.create(
    from_="+15017122661",
    to="+15558675310",
    body="Your order shipped."
)

# WhatsApp — same API, prefixed addresses
whatsapp = client.messages.create(
    from_="whatsapp:+15017122661",
    to="whatsapp:+15558675310",
    body="Your order shipped."
)
```

**Node.js**
```javascript
const client = require("twilio")(process.env.TWILIO_ACCOUNT_SID, process.env.TWILIO_AUTH_TOKEN);

// SMS
const sms = await client.messages.create({
    from: "+15017122661",
    to: "+15558675310",
    body: "Your order shipped.",
});

// WhatsApp — same API, prefixed addresses
const whatsapp = await client.messages.create({
    from: "whatsapp:+15017122661",
    to: "whatsapp:+15558675310",
    body: "Your order shipped.",
});
```

---

## Onboarding Sequence

Set up messaging in this order. Each step builds on the previous.

### Step 1: Foundation
Get a Twilio number, send your first SMS.
- `twilio-account-setup` → `twilio-sms-send-message`

### Step 2: Sender Strategy
Create a Messaging Service and add your numbers to a sender pool. Use `messagingServiceSid` instead of `from` for all production sends — this enables geo-match, sticky sender, and unlocks compliance features.
- `twilio-messaging-services`

### Step 3: Compliance
Register for A2P 10DLC (required for US SMS traffic). Set up opt-out handling.
- `twilio-compliance-onboarding` → `twilio-compliance-traffic`

### Step 4: Protect
Enable SMS pumping protection (prevents artificial traffic inflation) and compliance toolkit (quiet hours, reassigned number detection) on your Messaging Service.
- `twilio-messaging-services` (Compliance Toolkit + SMS Pumping Protection sections)

### Step 5: Add Channels
Add WhatsApp or other channels. Use Content Templates for cross-channel message formatting.
- `twilio-whatsapp-send-message` → `twilio-content-template-builder`

### Step 6: Monitor
Enable intelligent alerts for error pattern detection. Set up status callbacks for delivery tracking.
- `twilio-messaging-services` (Intelligent Alerts section) → `twilio-messaging-webhooks`

---

## CANNOT

- **Cannot send cross-channel in a single API call** — Each `messages.create()` targets one channel. For multi-channel fallback, implement sequencing in your application (e.g., try SMS, on failure send WhatsApp).
- **Cannot use WhatsApp free-form messages outside the 24-hour window** — After 24 hours since the user's last inbound message, you must use a pre-approved template. See `twilio-whatsapp-send-message`.
- **Cannot send MMS outside US, Canada, and Australia** — MMS is only supported on US/CA/AU numbers. For international rich media, use WhatsApp.
- **Cannot use SMS pumping protection or compliance toolkit without a Messaging Service** — These features are configured per Messaging Service. Raw `from` number sends don't get these protections.
- **Cannot mix channels in a single Messaging Service sender pool** — A Messaging Service manages phone numbers for SMS/MMS. WhatsApp senders are configured separately.
- **Cannot guarantee delivery on any channel** — SMS can be carrier-filtered, WhatsApp can queue-timeout (4 hours). Always implement status callbacks to track delivery.

---

## Next Steps

- **Send SMS:** `twilio-sms-send-message`
- **Send RCS:** `twilio-rcs-messaging`
- **Send WhatsApp:** `twilio-whatsapp-send-message`
- **Set up sender pools and production features:** `twilio-messaging-services`
- **Channel selection for marketing:** `twilio-marketing-promotions-advisor`
- **Channel selection for notifications:** `twilio-notifications-alerts-advisor`