Overview

Email Authentication enables users to authenticate and recover their Turnkey accounts using email-based verification. There are two methods of email authentication:

One-Time Password

• Uses a 6-digit one-time password sent via email
• Simple, and familiar user experience

Credential Bundle

• Sends an encrypted API key credential directly via email
• Alternative method for specific use cases
• More secure, but requires copying the full credential to the client

Both methods provide users with an expiring API key for authentication or account recovery.

Core Mechanism

Email Authentication is built with expiring API keys as the foundation. The two delivery mechanisms are:

OTP-based Method

The authentication process happens in two steps:

1. A 6-digit OTP code is sent to the user’s verified email address
2. Upon verification of the correct code, an API key credential is generated and encrypted for the client

Credential Bundle Method

The API key credential is encrypted and delivered directly through email to the user.

In both cases, once the credential is live on the client side (within the context of an iframe), it is readily available to stamp (authenticate) requests. See the enclave to end-user secure channel for more info on how we achieve secure delivery.

User Experience

OTP-based Authentication Flow

The flow begins with a new activity of type ACTIVITY_TYPE_INIT_OTP_AUTH with these parameters:

• otpType: specify "OTP_TYPE_EMAIL"
• contact: user’s email address (must match their registered email)
• emailCustomization: optional parameters for customizing emails
• userIdentifier: optional parameter for rate limiting SMS OTP requests per user. We recommend generating this server-side based on the user’s IP address or public key. See the OTP Rate Limits section below for more details.

After receiving the 6-digit code, users complete authentication with ACTIVITY_TYPE_OTP_AUTH:

• otpId: ID from the init activity
• otpCode: the 6-digit code received via email
• targetPublicKey: public key for credential encryption
• apiKeyName: optional name (defaults to OTP Auth - <Timestamp>)
• expirationSeconds: optional validity window (defaults to 15 minutes)
• invalidateExisting: optional boolean to invalidate previous OTP Auth API keys

OTP Rate Limits

In order to safeguard users, Turnkey enforces rate limits for OTP auth activities. If a userIdentifier parameter is provided, the following limits are enforced:

• 3 requests per 3 minutes per unique userIdentifier
• 3 retries max per code, after which point that code will be locked
• 3 active codes per user, each with a 5 minute TTL

Credential Bundle Authentication Flow

This alternative method uses ACTIVITY_TYPE_EMAIL_AUTH with these parameters:

• email: user’s email address (must match their registered email)
• targetPublicKey: public key for credential encryption
• apiKeyName: optional name (defaults to Email Auth - <Timestamp>)
• expirationSeconds: optional validity window (defaults to 15 minutes)
• emailCustomization: optional parameters for customizing emails
• invalidateExisting: optional boolean to invalidate previous Email Auth API keys

Recovery Flow

For account recovery scenarios, users can initiate a recovery-specific flow using the ACTIVITY_TYPE_INIT_USER_EMAIL_RECOVERY activity type, which requires:

• email: the email of the user needing recovery (must match their registered email)
• targetPublicKey: the public key for recovery credential encryption

The recovery process consists of two phases:

1. Initiation: Generates a temporary recovery credential and sends it via email
2. Finalization: User decrypts the recovery credential and uses it to sign an ACTIVITY_TYPE_RECOVER_USER activity, which can add new authenticators to regain account access

Authorization

Authorization is managed through our policy engine:

Authentication

Both OTP-based and credential bundle authentication activities:

• Can be performed by root users and users with proper policy authorization
• Require the respective feature to be enabled in the organization and sub-organization
• Can target any user in the organization or sub-organizations

Specifically:

• For OTP-based auth: ACTIVITY_TYPE_INIT_OTP_AUTH and ACTIVITY_TYPE_OTP_AUTH
• For credential bundle auth: ACTIVITY_TYPE_EMAIL_AUTH

Recovery

• ACTIVITY_TYPE_INIT_USER_EMAIL_RECOVERY:

  • Initiates the recovery process
  • Requires proper authorization via policies
  • Can target any user in the organization or sub-organizations

• ACTIVITY_TYPE_RECOVER_USER:

  • Must be signed by the recovery credential received via email
  • Users can add credentials to their own user when authenticated
  • Recovery credentials expire after 15 minutes
  • Only the most recent recovery credential remains valid
  • Users can add new authenticators to regain account access when authenticated with a recovery credential

Implementation in Sub-organizations

Both authentication methods and recovery work seamlessly with sub-organizations.

Example Implementations

• OTP Auth Example
• Email Auth Example
• Email Recovery Example
• Demo Embedded Wallet (code)

For implementation details:

Sub-Organization Email Auth Guide

Sub-Organization Recovery Guide

Implementation in Organizations

For organizations accessed via dashboard:

1. Ensure the required features are enabled:

   • FEATURE_NAME_OTP_EMAIL_AUTH for OTP-based authentication
   • FEATURE_NAME_EMAIL_AUTH for credential bundle authentication
   • Recovery features if needed

2. Users initiating the request must have appropriate permissions

Opting Out

Organizations can disable email-based features if their security model requires it:

Use ACTIVITY_TYPE_REMOVE_ORGANIZATION_FEATURE to disable:

• FEATURE_NAME_OTP_EMAIL_AUTH for OTP-based authentication
• FEATURE_NAME_EMAIL_AUTH for credential bundle authentication
• FEATURE_NAME_EMAIL_RECOVERY for recovery

When creating sub-organizations, use:

• disableOtpEmailAuth parameter for OTP-based authentication
• disableEmailAuth parameter for credential bundle authentication
• disableEmailRecovery parameter for recovery

Implementation Notes​

• Users are limited to:

  • 10 long-lived API keys
  • 10 expiring API keys (oldest are discarded when limit is reached)

For Top-level Organizations

• Both authentication methods are disabled by default
• Must be enabled via ACTIVITY_TYPE_SET_ORGANIZATION_FEATURE

For Sub-organizations

• Both authentication methods are enabled by default
• Can be disabled during creation using CreateSubOrganizationIntentV7 activity parameters

Example of enabling OTP-based Email Auth:

turnkey request --host api.turnkey.com --path /public/v1/submit/set_organization_feature --body '{
        "timestampMs": "'"$(date +%s)"'000",
        "type": "ACTIVITY_TYPE_SET_ORGANIZATION_FEATURE",
        "organizationId": "<YOUR-ORG-ID>",
        "parameters": {
                "name": "FEATURE_NAME_OTP_EMAIL_AUTH"
        }
}' --organization <YOUR-ORG-ID>

Example of enabling credential bundle Email Auth:

turnkey request --host api.turnkey.com --path /public/v1/submit/set_organization_feature --body '{
        "timestampMs": "'"$(date +%s)"'000",
        "type": "ACTIVITY_TYPE_SET_ORGANIZATION_FEATURE",
        "organizationId": "<YOUR-ORG-ID>",
        "parameters": {
                "name": "FEATURE_NAME_EMAIL_AUTH"
        }
}' --organization <YOUR-ORG-ID>