Implement Passwordless Email in Single-Page Apps

With an email connection, the user is asked to enter their email address, to which Auth0 sends a one-time code. The user then enters the code into your application.

If the email address attached to the code matches an existing user, Auth0 authenticates the user:

Existing User Flow

If the user is new, their user profile is created for the email connection before they are authenticated by Auth0.

New User Flow


Configure an email provider

By default, Auth0 sends the email from its own SMTP provider. Auth0's built-in email infrastructure should be used for testing-level emails only. You can configure your own email provider to better monitor and troubleshoot the email service as well as be able to fully customize the emails.

You will need to use your own email provider to be able to modify the From, Subject, and Body of Passwordless emails.

Configure the connection

  1. Navigate to the Connections > Passwordless page in the Auth0 Dashboard, and enable the Email toggle.

Enable Email Passwordless

  1. Select your Email Syntax, and enter your email's From, Subject, and Message text.

Configure Email Passwordless

You must change the From value to a non @auth0com address for your custom email to be sent. Otherwise the default email template will be sent.

  1. Enter any Authentication Parameters you would like to include in the generated sign-in link.

  2. Adjust settings for your OTP Expiry and OTP Length, and click SAVE.

If you choose to extend the amount of time it takes for your one-time password to expire, you should also extend the length of the one-time password code. Otherwise, an attacker has a larger window of time to attempt to guess a short code.

Multi-Language Support

The Message area supports multiple languages.

To choose the language, call the /passwordless/start authentication endpoint and set the value of the 'x-request-language' header. When this header is not set, the language is extracted from the 'accept-language' header, which is automatically set by the browser.

Message syntax

The Message area accepts Liquid syntax. You can use this syntax, combined with exposed parameter values, to programmatically construct elements of the message. For example, you can reference the request_language parameter to change the language of the message:

The following parameters are available when defining the message template:

Exposed Parameter Description
code The password to use
link The generated sign-in link The name of the application with which the user is signing up
request_language The requested language for message content
operation Indicates when the template has been triggered by an update to a user's email via the API. Equals change_email when triggered; otherwise, null.

Enable your apps

Click the Apps tab, and enable the apps for which you would like to use Passwordless Email.

Configure Cross-Origin Resource Sharing (CORS)

For security purposes, your app's origin URL must be listed as an approved URL. If you have not already added it to the Allowed Callback URLS for your application, you will need to add it to the list of Allowed Origins (CORS).

  1. Navigate to the Applications page in the Auth0 Dashboard.

  2. Click the name of your application to see its settings.

View Application Settings

  1. Scroll to Allowed Origins (CORS), enter your app's origin URL, then click Save Changes.

Enter Allowed Origin URL


Use Lock (the Auth0 UI widget)

Lock with Passwordless Mode is a professional-looking dialog that allows users to log in after receiving a one-time password via email or text message.

After installing Lock (version 11.2.0 or later), you must initialize it with your Client Id and domain. You can find this information in the Dashboard on your application settings page.

Then you can trigger the login with the following code:

If you use custom domains, replace YOUR_DOMAIN with your custom domain.

First, this will open a dialog that asks the user for their email address:

Then Auth0 will send an email to the user containing the one-time code:

Lock will ask for the code that has been emailed to the provided address. The code can then be used as a one-time password to log in.

Once the user enters the code received by email, Lock will authenticate them and call the callback function where the ID Token and profile will be available.

Use your own UI

Sample Project

Download a sample project specific to this tutorial configured with your Auth0 API Keys.

You can perform passwordless authentication in your SPA with your own custom UI using the Auth0 JavaScript SDK.

Construct a new instance of the Auth0 client as follows:

Be sure to provide a redirectUri and to set the responseType: 'token'.

You must provide a way for the user to enter a address to which the email will be sent. Then you can begin the passwordless authentication as follows (assuming the name of your form input as

This will send an email to the provided address. The user must now enter the code they received into your custom UI. Then you can continue with the login as follows (assuming the name of your form inputs as and input.code):

The passwordlessVerify method will verify the Passwordless transaction, then redirect the user back to the redirectUri that was set. You will then need to parse the URL hash in order to acquire the token, and then call the client.userInfo method to acquire your user's information, as in the following example:

Check out the Auth0.js SDK reference documentation for more information.