> ## Documentation Index
> Fetch the complete documentation index at: https://docs-dev-docs-event-stream-action-templates.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> The document announces support for Universal Login and Passwordless connections.

# Passwordless with Universal Login

<Card title="Before you start">
  * Configure a Passwordless connection. To learn how, read the following articles:

    * [Passwordless Authentication with Email](/docs/authenticate/passwordless/authentication-methods/email-otp)
    * [Passwordless Authentication with Magic Links](/docs/authenticate/passwordless/authentication-methods/email-magic-link)
    * [Passwordless Authentication with SMS](/docs/authenticate/passwordless/authentication-methods/sms-otp)
</Card>

The <Tooltip tip="Universal Login: Your application redirects to Universal Login, hosted on Auth0's Authorization Server, to verify a user's identity." cta="View Glossary" href="/docs/glossary?term=Universal+Login">Universal Login</Tooltip> Experience supports [Passwordless connections](/docs/authenticate/passwordless), which allow users to provide a phone number or email address, and then receive a one-time password (OTP) to complete authentication.

## Enable Passwordless for Universal Login

To configure Universal Login to support <Tooltip tip="Passwordless: Form of authentication that does not rely on a password as the first factor." cta="View Glossary" href="/docs/glossary?term=Passwordless">Passwordless</Tooltip> connections, you'll need to set the Authentication Profile to use a supported login flow, and update your application to specify the connection during authentication.

### Enable Identifier First

In the <Tooltip tip="Auth0 Dashboard: Auth0's main product to configure your services." cta="View Glossary" href="/docs/glossary?term=Auth0+Dashboard">Auth0 Dashboard</Tooltip>, go to [Authentication > Authentication Profile.](https://manage.auth0.com/?/authentication-profiles)

Select either **Identifier First** or **Identifier First + Biometrics**.

### Update your application

Depending on the type of connections you have enabled for your application, you may need to update your application to specify a Passwordless connection during login:

| Database connection | Passwordless connection | Need to specify? | User experience                                                                                |
| ------------------- | ----------------------- | ---------------- | ---------------------------------------------------------------------------------------------- |
| Yes                 | SMS and/or Email        | Yes              | Specified Passwordless connection is presented during login.                                   |
| No                  | SMS and Email           | No               | Passwordless connection that was created first is presented.                                   |
| No                  | SMS or Email            | No               | Passwordless connection is presented (along with any enabled Social connections) during login. |

To specify a Passwordless connection during login, you must pass the `connection` parameter and its value (either `sms` or `email`) to the [Auth0 Authentication API Login endpoint](https://auth0.com/docs/api/authentication#login):

`https://mytenant.us.auth0.com/authorize?client_id={id}&``connection={sms|email}``&scope=…&response_type=code&response_mode=query&state=…&redirect_uri=http%3A%2F%2Flocalhost%3A3000&code_challenge=…`

If you are using one of our SDKs, you can specify a Passwordless connection during initialization. For example:

```js lines theme={null}
auth0 = await createAuth0Client({
     domain: config.domain,
     client_id: config.clientId,
     connection: "email"
  });

auth0 = await createAuth0Client({
     domain: config.domain,
     client_id: config.clientId,
     connection: "sms"
  });
```

<Callout icon="file-lines" color="#0EA5E9" iconType="regular">
  If you are using Passwordless with Universal Login and [Single Sign-On](/docs/authenticate/single-sign-on), connection parameters `sms` and `email` do not utilize the existing Auth0 session, and the user will be prompted to log in.
</Callout>

### Test the connection

When the user is prompted to enter their OTP, they'll see one of the following screens:

### Signup

<Frame>
  <img src="https://mintcdn.com/docs-dev-docs-event-stream-action-templates/tcenw4jcNpftRqWN/docs/images/cdy7uua7fh8z/6ABY0ul7dceiGcdRH7glm6/617488990cb1f8f7f3f2b8efde866928/Passwordless_-_SMS_Enrollment_-_English.png?fit=max&auto=format&n=tcenw4jcNpftRqWN&q=85&s=a097a9b45f436e10c666db42b815c693" alt="" width="482" height="662" data-path="docs/images/cdy7uua7fh8z/6ABY0ul7dceiGcdRH7glm6/617488990cb1f8f7f3f2b8efde866928/Passwordless_-_SMS_Enrollment_-_English.png" />
</Frame>

### Login

<Frame>
  <img src="https://mintcdn.com/docs-dev-docs-event-stream-action-templates/tcenw4jcNpftRqWN/docs/images/cdy7uua7fh8z/5xHAEaXgnS43Jpnju9FCzZ/17e67c2901f6ec2a9a7421f65d84a1d1/Passwordless_Login_-_English.png?fit=max&auto=format&n=tcenw4jcNpftRqWN&q=85&s=7d51edf424ea2f882d951c53d9920043" alt="" width="482" height="658" data-path="docs/images/cdy7uua7fh8z/5xHAEaXgnS43Jpnju9FCzZ/17e67c2901f6ec2a9a7421f65d84a1d1/Passwordless_Login_-_English.png" />
</Frame>