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Twilio Verify Python Flask Quickstart

With just a few lines of code, your Python application can verify phone numbers and add an additional layer of security with Twilio Verify.

This Python Verify Quickstart will teach you how to do this using our Verify REST API, the Twilio Python helper library, and Python’s Flask microframework to ease development.

In this Quickstart, you will learn how to:

  1. Sign up for Twilio
  2. Set up your development environment to send and receive messages
  3. Send your first SMS phone verification
  4. Check verification codes

Sign up for Twilio

If you already have a Twilio account, you’re all set here! Feel free to jump to the next step.

Before you can send an SMS from Python, you'll need to sign up for a Twilio account or sign into your existing account.

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 verification messages to your phone from your Twilio account while in trial mode. This phone verification step is exactly what you'll learn how to build in this tutorial!
  • 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, create a verification service, and more.

Do I need a phone number?

If you've sent SMS with Twilio in the past, you might remember needing to buy a phone number. With Twilio Verify, we take care of that for you! The Verify API selects the best routes for quickly and reliably delivering verification codes globally.

Now that you have a Twilio account and a verification service, you can start writing some code! To make things even easier, we'll next install Twilio's official helper for Python applications.

Install Python and the Twilio Helper Library

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 verification.

To start a phone verification, you’ll need to have Python and the Twilio Python helper library installed.

Install Python

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:

python --version

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 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.

Clone and Setup the Verification Application

Start by cloning our Flask repository.

git clone git@github.com:TwilioDevEd/verify-v2-quickstart-python.git

If you don't have git installed or prefer to download the source code you can grab a zip file of the project here.

Set up your virtual environment and install dependencies

If you're not familiar with Python virtual environments, follow our tutorial for setting up your local Python environment. Navigate into the project folder and create your virtual environment.

cd verify-v2-quickstart-python

virtualenv venv
source venv/bin/activate

pip install -r requirements.txt

Copy .env.example to .env. This is where we'll store sensitive data in environment variables.

cp .env.example .env

Run the application

export FLASK_APP=verify
export FLASK_ENV=development
flask init-db
flask run

Or on Windows cmd:

set FLASK_APP=verify
set FLASK_ENV=development
flask init-db
flask run

If your credentials are set up correctly you'll soon get a message that the app is up!

Use the Flask Twilio Verify Demo

Navigate to http://localhost:5000/auth/register. You should see a registration form that looks like this:

sign up form with phone verification
Enter your phone number and choose which channel to request verification over. Finally hit the green Sign Up button and wait. You'll either receive a phone call or an SMS with the verification token. If you requested a phone call, as an additional security feature you may need to interact to proceed (the call will tell you to enter a number on the phone keypad).

Enter the token into the Verification entry form and click 'Verify':

verification entry form

And with that, your demo app is protected with Twilio's Phone Verification! You can now log out to try the untried channel.

What's Next?

Your demo app is now keeping fraudulent users from registering with your business and polluting your database. Next, check out all of the variables and options available to you in the Phone Verification API Reference. Also, to protect your customers in an ongoing manner (with this same codebase) try the Python Flask Authy Two-Factor Authentication Quickstart.

After that, visit the Docs for more Account Security demos and tutorials and web applications using all of Twilio's products.

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Need some help?

We all do sometimes; code is hard. Get help now from our support team, or lean on the wisdom of the crowd browsing the Twilio tag on Stack Overflow.