Use Twilio to send text messages

Cost

Paid. Twilio charges per message and per phone number. No open source service can deliver text messages, because that needs contracts with phone carriers in each country.

How to do it

Twilio's Python SDK dates from November 2009, and its npm package reached 1.0.0 in March 2013. The npm SDK 6.2.0 and the Python SDK 9.12.0 shipped on 12 October 2026. They had about 3.7 and 5.2 million weekly downloads, both MIT-licensed. Messages still go to the 2010-04-01 API path, so the interface has stayed stable for 16 years. Numbers and opt-outs are your own data, and sender registrations can move to another carrier. Follow Register every sender before you send and Guard text sending against SMS pumping. Choose something else when your app already runs on one cloud and sends only codes. AWS End User Messaging or Vonage then save a second vendor.

Examples

Using these examples: they show one way to follow this rule. Keep the behaviour and the check, not the syntax. Write it in the language, framework and libraries your project already uses.

JavaScript example

import twilio from 'twilio';

const client = twilio(process.env.TWILIO_ACCOUNT_SID, process.env.TWILIO_AUTH_TOKEN);

export const sendText = (to, body) => client.messages.create({
  to, body, messagingServiceSid: process.env.TWILIO_MESSAGING_SERVICE_SID,
});

Python example

import os
from twilio.rest import Client

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

def send_text(to: str, body: str):
    return client.messages.create(to=to, body=body, messaging_service_sid=os.environ["TWILIO_MESSAGING_SERVICE_SID"])

How to check

Every send names a Messaging Service, not a single sender number. Every stored phone number matches ^\+[1-9]\d{1,14}$.

Sources

• Twilio Message resource

Related rules

• Register every sender before you send in Notifications
• Guard text sending against SMS pumping in Notifications