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:
- Sign up for Twilio and get your first SMS-enabled Twilio phone number
- Set up your development environment to send and receive messages
- Send your first SMS
- Receive inbound text messages
- Reply to incoming messages with an SMS
Prefer to get started by watching a video? Check out our Python SMS Quickstart video on Youtube.
If you already have a Twilio account and an SMS-enabled Twilio phone number, you’re all set here! Feel free to jump to the next step.
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, authentication token, find a Twilio phone number, and more.
If you don't currently own a Twilio phone number with SMS functionality, you'll need to purchase one. After navigating to the Buy a Number page, check the "SMS" box and click "Search."
You’ll then see a list of available phone numbers and their capabilities. Find a number that suits your fancy and click "Buy" to add it to your account.
Now that you have a Twilio account and a programmable phone number, you can start writing some code! To make things even easier, we'll next install Twilio's official helper library for Python applications.
If you’ve gone through one of our other Python Quickstarts already and have Python and the Twilio Python helper library installed, you can skip this step and get straight to sending your first text message.
To send your first SMS, you’ll need to have Python and the Twilio Python helper library installed.
If you’re using a Mac or Linux machine, you probably already have Python installed. You can check this by opening up a terminal and running the following command:
You should see something like:
$ python --version Python 3.4 # Python 2.7+ is okay too
Windows users can follow this excellent tutorial for installing Python on Windows, or follow the instructions from Python's documentation.
Twilio’s Python server-side SDK supports both Python 2 and Python 3. You can use either version for this quickstart, but we recommend using Python 3 for future projects with Twilio unless there are specific libraries your project needs which are only compatible with Python 2.
The easiest way to install the library is using pip, a package manager for Python that makes it easier to install the libraries you need. Simply run this in the terminal:
pip install twilio
If you get a
pip: command not found error, you can also use
easy_install by running this in your terminal:
If you'd prefer a manual installation, you can download the source code (ZIP) for
twilio-python and then install the library by running:
python setup.py install
in the folder containing the twilio-python server-side SDK library code.
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:
Swap the placeholder values for
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:
send_sms.py and replace the values for
auth_token with your unique values.
Please note: it's okay to hardcode your credentials when getting started, but you should use environment variables to keep them secret before deploying to production. Check out how to set environment variables for more information.
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.
If you are on a Twilio Trial account, your outgoing SMS messages are limited to phone numbers that you have verified with Twilio. Phone numbers can be verified via your Twilio Console's Verified Caller IDs.
When you send an SMS from your free trial phone number, it will always begin with "Sent from a Twilio trial account." We remove this message after you upgrade.
Save your changes and run this script from your terminal:
That's it! In a few moments, you should receive an SMS from your Twilio number on your phone.
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.
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:
If you’re using Python 2.5-2.7, run the following command in your terminal, specifying your version number:
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.
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:
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:
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.
Now we’re ready to install Flask. Create a file called
requirements.txt and add the following lines to it:
Then install both of these packages with pip in your terminal:
bin/pip install -r requirements.txt
First, make sure your virtualenv is activated:
cd Documents/my_sms_quickstart_folder source bin/activate # On Windows, use .\bin\activate.bat
Then, create and open a file called
run.py and add these lines:
from flask import Flask app = Flask(__name__) @app.route("/sms") def hello(): return "Hello World!" if __name__ == "__main__": app.run(debug=True)
Now it's time to try running it. In your terminal, type:
You should see:
* Running on http://127.0.0.1:5000/
Navigate to http://localhost:5000/sms in your browser. You should see a "Hello World!" message. You’re ready to create your first Twilio messaging app!
If you encountered any issues or want instructions on setting up your environment with an older Python version (<3.4), check out our full guide to setting up a local Python dev environment.
We’re about to build a small Flask application to receive incoming messages. Before we do that, we need to make sure that Twilio can reach your application.
Most Twilio services use webhooks to communicate with your application. When Twilio receives an SMS, for example, it reaches out to a URL in your application for instructions on how to handle the message.
When you’re working on your Flask application in your development environment, your app is only reachable by other programs on your computer, so Twilio won’t be able to talk to it. We need to solve this problem by making your application accessible over the internet.
While there are a lot of ways to do this, like deploying your application to Heroku or AWS, you'll probably want a less laborious way to test your Twilio application. For a lightweight way to make your app available on the internet, we recommend a tool called Ngrok. Once started, Ngrok provides a unique URL on the ngrok.io domain which forwards incoming requests to your local development environment.
It works something like this:
If you don’t already use Ngrok, head over to their download page and grab the appropriate binary for your operating system. Once downloaded, unzip the package.
If you're working on a Mac or Linux, you're all set. If you're on Windows, follow our guide on how to install and configure ngrok on Windows. For more info on ngrok, including some great tips and tricks, check out this in-depth blog post.
Once downloaded, start that Hello World application we made previously:
Your local application must be running locally for Ngrok to do its magic.
Then open a new terminal tab or window and start Ngrok with this command:
./ngrok http 5000
If your local server is running on a different port, replace 5000 with the correct port number.
You should see output similar to this:
Copy your public URL from this output and paste it into your browser, appending our
/sms route to the ngrok URL. You should see your Flask application's "Hello, World!" message.
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. Once you receive the request, you can tell Twilio to reply with an SMS, kick off a phone call, store details about the SMS in your database, or trigger something else entirely - it’s all up to you!
For this Quickstart, we’ll have our Flask app reply to incoming SMS messages with a thank you to the sender. Open up
run.py again and update the code to look like this code sample:
Save this file and restart your app with
Double-check that Ngrok is still running on your localhost port. Now Twilio will be able to find your application - but first, we need to tell Twilio where to look.
For Twilio to know where to look, you need to configure your Twilio phone number to call your webhook URL whenever a new message comes in.
- Log into Twilio.com and go to the Console's Numbers page.
- Click on your SMS-enabled phone number.
- Find the Messaging section. The default “CONFIGURE WITH” is what you’ll need: "Webhooks/TwiML".
- In the “A MESSAGE COMES IN” section, select "Webhook" and paste in the URL you want to use. Make sure to add the
/smsroute to the end of your ngrok URL here:
Save your changes - you’re ready!
As long as your localhost and the Ngrok servers are up and running, we’re ready for the fun part - testing our new Flask application!
Send a text message from your mobile phone to your Twilio phone number. You should see an HTTP request in your Ngrok console. Your Flask app will process the text message, and you’ll get your response back as an SMS.
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!