To enable Email OTP (One-Time Password) feature in a self-hosted open-source version of Ory Kratos, follow these steps: ## 1. Configure your identity schema First, ensure your identity schema has an email field marked as an identifier for the code method:

json {   "$id": "<https://schemas.ory.sh/presets/kratos/identity.email.schema.json>",   "title": "Person",   "type": "object",   "properties": {     "traits": {       "type": "object",       "properties": {         "email": {           "type": "string",           "format": "email",           "title": "E-Mail",           "<http://ory.sh/kratos|ory.sh/kratos>": {             "credentials": {               "code": {                 "identifier": true,                 "via": "email"               }             }           },           "maxLength": 320         }       },       "required": ["email"],       "additionalProperties": false     }   } }

## 2. Enable the code method in your configuration Update your Kratos configuration file (kratos.yml) to enable the code method:

yaml selfservice:   methods:     code:       enabled: true       passwordless_enabled: true  # Enable this for passwordless login       config:         lifespan: 15m  # Defines how long the code is valid for

## 3. Configure SMTP for email delivery Set up your SMTP connection to send the one-time codes:

yaml courier:   smtp:     connection_uri: <smtps://username:password@smtp-server:1234/>

## 4. Configure the login flow (optional) If you want to use identifier-first authentication (where users enter their email first, then get a code):

yaml selfservice:   flows:     login:       style: identifier_first

## 5. Restart Ory Kratos After making these configuration changes, restart your Ory Kratos instance to apply them. These steps will enable Email OTP functionality in your self-hosted Ory Kratos instance. Users will be able to authenticate using one-time codes sent to their email addresses. Sources: [Passwordless one-time code login identifier](https://www.ory.sh/docs/kratos/manage-identities/customize-identity-schema#passwordless-one-time-code-login-identifier) [Email and SMS one-time-code authentication](https://www.ory.sh/docs/kratos/passwordless/one-time-code) [Identifier first authentication](https://www.ory.sh/docs/identities/sign-in/identifier-first-authentication)

In Ory Kratos, the

connection_uri

is a configuration parameter used to specify the connection details for the SMTP server that will be used to send emails. This is particularly important for features like email verification, account recovery, and one-time password (OTP) authentication. The

connection_uri

follows a URL-like format that includes: - Protocol (smtp or smtps) - Username and password - Server address - Port number - Optional parameters For example:

<smtp://username:password@server:port/>

It's important to note that the username and password must be [URI encoded](https://en.wikipedia.org/wiki/Percent-encoding) to properly handle special characters. Different security mechanisms can be specified in the `connection_uri`: 1. StartTLS with certificate verification (recommended):

<smtp://username:password@server:port/>

2. StartTLS without certificate verification:

<smtp://username:password@server:port/?skip_ssl_verify=true>

3. Cleartext SMTP (not secure, for development only):

<smtp://username:password@server:port/?disable_starttls=true>

4. Implicit TLS with certificate verification:

<smtps://username:password@server:port/>

5. Other variations with different security options When configuring your self-hosted Ory Kratos for email delivery, you would include this in your configuration file:

yaml courier:   smtp:     connection_uri: <smtp://username:password@server:port/>     from_address: <mailto:noreply@yourdomain.com|noreply@yourdomain.com>     from_name: Your Company Name

[Use a custom server to send Ory Identity messages to users](https://www.ory.sh/docs/kratos/emails-sms/sending-emails-smtp) provides more detailed information about configuring SMTP for Ory Kratos.

I understand you're encountering a 400 error when using the login flow endpoint after setting up Email OTP in Ory Kratos. This is actually expected behavior in certain scenarios with Ory Kratos, particularly when using the passwordless login with one-time codes. ## Why you're seeing a 400 error When requesting a login code via email for passwordless login, Ory Kratos returns HTTP 400 status code even though the request is valid and the email with the code is successfully sent. This is a known behavior that has been reported in [GitHub issue #4052](https://github.com/ory/kratos/issues/4052). The reason behind this design is explained in the issue: 1. Ory Kratos returns 200 only on successful login completion 2. The first step (requesting the code) is considered an intermediate step, not a completed login 3. The 400 response contains the updated flow information needed for the next step ## Troubleshooting steps 1. Check the response body: Despite the 400 status code, the response body should contain the updated flow information with a message indicating that the code has been sent. 2. Verify in the logs: Check if the email was actually sent by looking at your logs. 3. Common issues to check: - Make sure you're starting and finishing the request in the same browser - Ensure your SMTP configuration is correct - Verify your identity schema is properly configured for the code method 4. Implementation approach: When implementing the client side, you'll need to handle the 400 response as a successful intermediate step rather than an error when the response contains the expected flow information. As mentioned in the [troubleshooting documentation](https://www.ory.sh/docs/kratos/debug/troubleshooting), a "400: Bad Request" on self-service flows doesn't necessarily mean your request was invalid. This behavior has been discussed extensively, and while it might seem counterintuitive from an HTTP standards perspective, it's the current design of Ory Kratos for this specific flow. If you need further assistance, you might want to check the complete response body to ensure it contains the expected flow information and not an actual error. Would you like me to help you interpret the response body or suggest a specific implementation approach for handling this behavior?