twilio-sms-send-message

## Overview **SMS is one channel in Twilio's Messaging platform.** All channels — SMS, WhatsApp, RCS, Facebook Messenger — share the same `messages.create()` API. See `twilio-messaging-overview` for the full channel comparison and onboarding sequence. | When to use SMS | When to consider alternatives | |----------------|------------------------------| | Reach any phone number globally | Need rich media outside US/CA/AU → WhatsApp | | No app install required | Opted-in audience prefers chat apps → WhatsApp | | Time-sensitive alerts (OTP, outage) | Marketing campaigns → `twilio-marketing-promotions-advisor` | | Regulatory/compliance requires SMS | Cost-sensitive high-volume → WhatsApp (lower per-msg cost in many markets) | **For production SMS:** Use a Messaging Service (`messagingServiceSid`) instead of a raw `from` number. It enables sender pool management, compliance toolkit, SMS pumping protection, link shortening, and message scheduling. See `twilio-messaging-services`. Every outbound SMS requires a `from` Twilio number (or `messagingServiceSid`) and a `to` recipient — both in E.164 format. --- ## Prerequisites - Twilio account with an SMS-capable phone number — New to Twilio? See `twilio-account-setup` for signup, getting a number, and trial limitations - 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` --- ## Quickstart **Python** ```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_="+15017122661", # Your Twilio number (E.164) to="+15558675310", # Recipient (E.164) body="Your appointment is confirmed for tomorrow at 2pm." ) print(message.sid) # SMxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx print(message.status) # queued | sent | delivered | failed ``` **Node.js** ```node const twilio = require("twilio"); const client = twilio(process.env.TWILIO_ACCOUNT_SID, process.env.TWILIO_AUTH_TOKEN); const message = await client.messages.create({ from: "+15017122661", to: "+15558675310", body: "Your appointment is confirmed for tomorrow at 2pm.", }); console.log(message.sid); console.log(message.status); ``` --- ## Key Patterns ### Send MMS (with media) **Python** ```python message = client.messages.create( from_="+15017122661", to="+15558675310", body="Here is your invoice.", media_url=["https://example.com/invoice.pdf"] ) ``` **Node.js** ```node const message = await client.messages.create({ from: "+15017122661", to: "+15558675310", body: "Here is your invoice.", mediaUrl: ["https://example.com/invoice.pdf"], }); ``` Supported media types: images (JPEG, PNG, GIF), PDF, audio, video. Max 5 MB per message. ### Send via Messaging Service (recommended for scale) Use `messagingServiceSid` instead of `from` — Twilio picks the best sender automatically from your pool. **Python** ```python message = client.messages.create( messaging_service_sid="MGxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx", to="+15558675310", body="Your order has shipped." ) ``` **Node.js** ```node const message = await client.messages.create({ messagingServiceSid: "MGxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx", to: "+15558675310", body: "Your order has shipped.", }); ``` ### Track Delivery Status **Python** ```python message = client.messages.create( from_="+15017122661", to="+15558675310", body="Hello!", status_callback="https://yourapp.com/sms-status" ) ``` **Node.js** ```node const message = await client.messages.create({ from: "+15017122661", to: "+15558675310", body: "Hello!", statusCallback: "https://yourapp.com/sms-status", }); ``` Twilio POSTs to your URL at each transition: `queued → sent → delivered` (or `failed`/`undelivered`). --- ## Response Fields | Field | Description | |-------|-------------| | `sid` | Message identifier (`SM...`) | | `status` | `queued`, `sent`, `delivered`, `undelivered`, `failed` | | `error_code` | Populated on failure | | `error_message` | Human-readable description | | `price` | Cost (populated after delivery) | | `date_sent` | UTC timestamp | --- ## Common Errors | Code | Meaning | Fix | |------|---------|-----| | 21211 | Invalid `to` number | Validate E.164 format | | 21408 | Permission to send to region not enabled | Enable geo-permissions in Console | | 21610 | Number is on blocklist (opted out) | Do not retry; respect opt-out | | 30003 | Unreachable destination | Carrier cannot deliver; try later | | 30007 | Message filtered as spam | Review content and sender reputation | | 30034 | Message from unregistered number | Complete A2P 10DLC registration — see `twilio-compliance-onboarding` | | 30450 | SMS pumping detected | Message blocked by SMS pumping protection — see `twilio-messaging-services` | ### Messages Being Filtered or Blocked? If your messages aren't being delivered, check these causes in order: 1. **Unregistered sender (error 30034)** — US 10DLC numbers must be registered. See `twilio-compliance-onboarding` 2. **Spam filtered (error 30007)** — Carrier flagged content. Check: opt-out language included? URL shorteners avoided? Content matches registered campaign? 3. **Opted-out recipient (error 21610)** — Recipient sent STOP. Do not retry. See `twilio-compliance-traffic` 4. **Geo-permissions disabled (error 21408)** — Enable the destination country in Console > Messaging > Settings > Geo Permissions. See `twilio-security-hardening` 5. **SMS pumping (error 30450)** — Artificial traffic detected. Whitelist known prefixes via Global Safe List. See `twilio-messaging-services` 6. **Account suspended** — Check Console for account status notifications. See `twilio-account-setup` For delivery event tracking, set up StatusCallbacks or use `twilio-debugging-observability`. --- ## CANNOT - **Cannot send without E.164 format** — Both `from` and `to` must be `+` followed by country code and number - **Cannot send to unverified numbers on trial accounts** — Upgrade to paid or verify recipient numbers first - **Cannot send MMS outside US, Canada, and Australia** — MMS is only supported on US/CA/AU numbers; for international rich media use WhatsApp - **Cannot exceed 1,600 characters per message** — Longer messages are automatically split into segments (each billed separately) - **Cannot prevent SMS pumping without a Messaging Service** — Enable SMS pumping protection via Messaging Services to prevent artificial traffic inflation. See `twilio-messaging-services` --- ## Next Steps - **Channel overview and onboarding guide:** `twilio-messaging-overview` - **Receive inbound SMS and delivery status:** `twilio-messaging-webhooks` - **Manage sender pools at scale:** `twilio-messaging-services` - **US compliance for A2P traffic:** `twilio-compliance-onboarding` - **Send via WhatsApp instead:** `twilio-whatsapp-send-message`