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Account Verification with Authy, Python and Flask

For new development, we encourage you to use the Verify API instead of the Authy API. The Verify API is an evolution of the Authy API with continued support for SMS, voice, and email one-time passcodes, an improved developer experience and new features including:

  • Twilio helper libraries in JavaScript, Java, C#, Python, Ruby, PHP, and Golang
  • Access via the Twilio CLI
  • Improved Visibility and Insights
  • Push authentication SDK embeddable in your own application

You are currently viewing the Authy API. New features and development will be on the Verify API. Check out the FAQ for more information and the migrating to Verify guide to get started.

Ready to add Authy user account verification to your Flask application? Don't worry, this will be the easiest thing you do all day.

Here's how it all works at a high level:

  1. A user begins the registration process by entering their information (including a phone number) into a signup form.
  2. The authentication system sends a one-time password to the user's mobile phone to verify the phone number.
  3. The user enters that one-time password into a form to complete registration.
  4. The user sees a success page and receives an SMS alerting them that their account has been created!

Building Blocks

To get this done, you'll be working with the following Twilio-powered APIs:


  • Authy Docs: Find quickstarts, documentation, and info on the helper libraries.


  • Messages Resource: We will use Twilio directly to send our users a confirmation message after they creates their accounts.

        Initialize Flask application


        All of this can be done in under a half an hour with the simplicity and power of Authy and Twilio. Let's get started!

        Click me to move on to the next step!

        Application configuration

        For this application we'll be using the The Twilio Python Helper Library and the Python Client for Authy API. We require some configuration from your side before we can begin.

        Edit the DevelopmentConfig class constant values located in the account_verification_flask/ file:

        AUTHY_KEY = 'your_authy_key'
        TWILIO_ACCOUNT_SID = 'your_twilio_account_sid'
        TWILIO_AUTH_TOKEN = 'your_twilio_auth_token'
        TWILIO_NUMBER = 'your_twilio_phone_number'
        SQLALCHEMY_DATABASE_URI = 'sqlite://'

        Note that you have to replace the placeholders your_twilio_account_sid, your_twilio_auth_token, your_twilio_phone_number and your_authy_key with your information. You can find all of those parameters (and more) in your Twilio Account Console and your Authy dashboard.


              Configure your application with Twilio and Authy


              Now that we've got the setup boilerplate out of the way, let's take a look at the User model.

              Visit our user model

              The User Model

              The User Model for this tutorial is pretty straight-forward. Note the new variable authy_user_id, which is implemented for storing the user's Authy identification token.

              We'll be using the Flask-Login library for our user session management. To integrate this library into our code we need to implement a few properties and methods, then we're good to go.


                    User model with DB configuration and model methods for Flask-Login


                    Pretty simple User model, right? Next we're going to visit the registration form on the client side.

                    Take a look at the user registration form

                    Registration Form

                    In order to validate the user's account and register the user, we need a mobile number with a country code. We can then use Authy to send a verification code via SMS.

                    In this example we're validating and rendering the forms with the WTForms library. This allows us to define the forms as classes inside Python.


                          User registration form


                          That's it for the client side. Now let's look at what happens when the user submits the form.

                          Let's look at the form code on the server side

                          Registration Server Side Implementation

                          Next our controller stores the new user, registers them with Authy's API, and requests a new verification code.


                                The registration view route


                                Next we'll set up our application to complete our user verification.

                                What happens when a verification code comes in?

                                Verifying a User in Python

                                On the server we first check that the email belongs to a user that we haven't yet verified.

                                The process then has two critical steps:

                                1. Communicate with Authy's API to check if the given code is correct.

                                2. Send a confirmation SMS to the user using Twilio's API.

                                After that (assuming a success!) we redirect the user to a success page.


                                      Verify a user's code and send a success SMS


                                      What happens if the message was never sent, didn't arrive, or can't be found? Let's look at how to handle those scenarios next.

                                      And how about handling exceptions?

                                      Re-sending a Verification Code

                                      The form for re-sending the code is a single line, so let's skip that detail for this tutorial. Instead, let's just take a look at the controller function for resending verifications.

                                      This controller loads the User associated with the request and then uses the same Authy API method we used earlier to resend the code. Pretty straightforward, right?


                                            Re-send a verification code


                                            Let's take a step back and see how we can use Authy to resend a verification code to an unverified user.

                                            Send a token on account creation

                                            Sending a Token on Account Creation

                                            In order to end up with a cleaner and decoupled design we'll encapsulate all of Authy's related features in an AuthyService. This class will hold a shared class instance of the AuthyApiClient class.

                                            Once the user has an authyId we can send a verification code to that user's mobile phone.


                                                  Send Authy token via SMS


                                                  When our user is created successfully via the form we have implemented, we send a token to the user's mobile phone asking them to verify their account in our controller. When the code is sent, we redirect our users to another page where they can enter the received token, completing the verification process.

                                                  Next: Verifying the user's code with Authy

                                                  Verifying the Code

                                                  Authy provides us with a tokens.verify method that allows us to pass a user id and token. In this case we just need to check that the API request was successful and, if so, set a verified flag on the user.


                                                        Verify a user's token with AuthyServices


                                                        That's it for token verification! Let's provide a nice user onboarding experience, and send a confirmation message to our new user.

                                                        Wrap it up with a nice confirmation message

                                                        Sending the Confirmation Message

                                                        Just as we did for our Authy client, we create a single instance of the Twilio REST API helper. It will be called twilio_client in this example.

                                                        After that, it's straightforward - send an SMS using the Twilio Python helper library to the same number we used in messages.create().


                                                              Send a registration success SMS from the TwilioServices class


                                                              Congratulations! You've successfully verified new user accounts with Authy. Where can we take it from here?

                                                              Now you're an expert on Authy. Where to next?

                                                              Where to Next?

                                                              In one simple tutorial, we've implemented account verification with Authy and Twilio, allowing your users to confirm accounts with their phone number! Now it's on you - let us know what you build on Twitter, and check out these other tutorials:

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                                                              Two-Factor Authentication with Authy

                                                              Use Twilio and Twilio-powered Authy OneTouch to implement two-factor authentication (2FA) in your web app.

                                                              Kevin Whinnery Kelley Robinson Hector Ortega David Prothero Kat King Andrew Baker Jose Oliveros Paul Kamp
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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 by visiting Twilio's Community Forums or browsing the Twilio tag on Stack Overflow.


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