Twilio SMS Python Quickstart

With just a few lines of code, your Python application can send and receive text messages with Twilio Programmable SMS.

This Python SMS Quickstart will teach you how to do this using our Communications REST API, the Twilio Python helper library, and Python’s Flask microframework to ease development. Prefer to use Django? Check out this blog post.

In this Quickstart, you will learn how to:

1. Sign up for Twilio and get your first SMS-enabled Twilio phone number
2. Set up your development environment to send and receive messages
3. Send your first SMS
4. Receive inbound text messages
5. Reply to incoming messages with an SMS

Prefer to get started by watching a video? Check out our Python SMS Quickstart video on Youtube.

Sign up for - or sign in to - Twilio

You can sign up for a free Twilio trial account here.

• When you sign up, you'll be asked to verify your personal phone number. This helps Twilio verify your identity and also allows you to send test messages to your phone from your Twilio account while in trial mode.
• Once you verify your number, you'll be asked to create a project. For the sake of this tutorial, you can click on the "Learn and Explore" template. Give your project a name, or just click "skip remaining steps" to continue with the default.
• Once you get through the project creation flow, you'll arrive at your project dashboard in the Twilio Console. This is where you'll be able to access your Account SID an authentication token, find a Twilio phone number, and more.

Install the Twilio CLI

We'll need to use the Twilio CLI (command line interface) for a few tasks, so let's install that next.

Run twilio login to get the Twilio CLI connected to your account. Visit https://www.twilio.com/console, and you’ll find your unique Account SID and Auth Token to provide to the CLI.

You can reveal your auth token by clicking on the eyeball icon:

Get a phone number

If you don't currently own a Twilio phone number with SMS functionality, you'll need to purchase one. With the CLI, run:

twilio phone-numbers:buy:local --country-code US --sms-enabled

Select a phone number to add it to your account.

Next, we need to install Python and the Twilio Python Helper Library.

Install Python and the Twilio Helper Library

To send your first SMS, you’ll need to have Python and the Twilio Python helper library installed.

Send an outbound SMS with Python

Now that we have Python and twilio-python installed, we can send an outbound text message from the Twilio phone number we just purchased with a single API request. Create and open a new file called send_sms.py and type or paste in this code sample.

You’ll need to edit this file a little more before your message will send:

Replace the placeholder credential values

Swap the placeholder values for account_sid and auth_token with your personal Twilio credentials. Go to https://www.twilio.com/console and log in. On this page, you’ll find your unique Account SID and Auth Token, which you’ll need any time you send messages through the Twilio Client like this. You can reveal your auth token by clicking on the 'view' link:

Open send_sms.py and replace the values for account_sid and auth_token with your unique values.

Replace the from_ phone number

Remember that SMS-enabled phone number you bought just a few minutes ago? Go ahead and replace the existing from_ number with that one, making sure to use E.164 formatting:

[+][country code][phone number including area code]

Replace the to phone number

Replace the to phone number with your mobile phone number. This can be any phone number that can receive text messages, but it’s a good idea to test with your own phone so you can see the magic happen! As above, you should use E.164 formatting for this value.

Save your changes and run this script from your terminal:

python send_sms.py

That's it! In a few moments, you should receive an SMS from your Twilio number on your phone.

Are your customers in the U.S. or Canada? You can also send them MMS messages by adding just one line of code. Check out this guide to sending MMS to see how it's done.

Receive and reply to inbound SMS messages with Python

When someone sends an SMS to your Twilio phone number, Twilio makes an HTTP request to your server asking for instructions on what to do next. For this Quickstart, we’ll reply to the sender with a note about how we're sending our SMS reply.

In order to receive and reply to incoming SMS messages, we'll need to create a very lightweight web application that can accept incoming requests. We'll use Flask for this Quickstart, but if you prefer to use Django, you can find instructions in this blog post.

For instructions on setting up Flask on Windows, you can check out this handy guide.

Install Pip and Virtualenv

To install Flask and set up our development environment, we’ll need two tools: pip to install Flask and virtualenv to create a unique sandbox for this project. If you already have these tools installed, you can skip this section.

Pip comes pre-packaged with Python 3.4+, so if you’re on a recent version of Python, you don’t need to install anything new. If you’re on an earlier version, never fear: pip is included in virtualenv. So let’s install virtualenv!

If you’re using Python 2.4, run the following command in your terminal:

easy_install virtualenv

If you’re using Python 2.5-2.7, run the following command in your terminal, specifying your version number:

easy_install-2.7 virtualenv

Replace the 2.7 with 2.5 or 2.6 if you have that version installed.

To install virtualenv with Python 3.4+:

# If you get 'permission denied' errors try running "sudo python" instead of "python"
pip install virtualenv

If you get any errors in this step, check out these tips for debugging.

Create and activate your virtual environment

Once you have virtualenv installed, use your terminal to navigate to the directory you’re using for this Quickstart and create a virtual environment:

cd Documents/my_sms_quickstart_folder
virtualenv --no-site-packages .

Now, activate the virtual environment:

source bin/activate     # On Windows, use .\Scripts\activate.bat

You can verify that your virtualenv is running by looking at your terminal: you should see the name of the enclosing folder. It will look something like this:

(sms_quickstart)USER:~ user$

If you wish to point your virtual environment to a Python version that’s different from your default or just want to learn more about virtualenv, see this thorough guide.

Install dependencies

Now we’re ready to install Flask. Create a file called requirements.txt and add the following lines to it:

Flask>=0.12
twilio~=6.0.0

Then install both of these packages with pip in your terminal:

bin/pip install -r requirements.txt

Test everything from scratch

First, make sure your virtualenv is activated:

cd Documents/my_sms_quickstart_folder
source bin/activate     # On Windows, use .\Scripts\activate.bat

Then, create and open a file called run.py and add the code from this example:

Now it's time to try running it. In your terminal, type:

python run.py

You should see:

* Running on http://127.0.0.1:5000/

Navigate to http://localhost:5000/sms in your browser. You should see an "Ahoy!" message. You’re ready to create your first Twilio messaging app!

Configure your Webhook URL

Now, you need to configure your Twilio phone number to call your webhook URL whenever a new message comes in. Just run this CLI command, replacing the phone number with your Twilio phone number:

twilio phone-numbers:update "+15017122661" --sms-url="http://localhost:5000/sms"

The CLI will start an ngrok tunnel (so Twilio can reach your development machine) and wait patiently for incoming text messages!

Test your application with a text

Now that everything is glued together, it's time to test.

Send a text message from your mobile phone to your Twilio phone number. You'll see a couple of things happen very quickly -

1. Your Flask app will note a new connection
2. Twilio will forward your response back as an SMS!

Where to next?

Now that you know the basics of sending and receiving SMS and MMS text messages with Python, you might want to check out these resources.

• Dive into the API Reference documentation for Twilio SMS
• Learn how to create an SMS conversation in Python
• Track the delivery status of your messages with Python
• Send an SMS during a phone call
• Learn how to build cool things with TwilioQuest, our interactive, self-paced game that teaches you how to Twilio.

We can't wait to see what you build!