> ## Documentation Index
> Fetch the complete documentation index at: https://docs.kerne.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Start passwordless login or signup

> Emails a one-click link for the given address. If the email belongs to an existing user, it's a login link; otherwise, when registration allows it, this creates the account first and the link both confirms the email and logs them in. Always responds identically regardless of outcome.



## OpenAPI

````yaml /openapi.json post /v1/auth/passwordless/start
openapi: 3.0.0
info:
  title: Kerne API
  description: >-
    Kerne SaaS Foundation as a Service - authentication, authorization, and
    billing management. Errors follow standardized error codes (K1xxx-K9xxx)
    documented at https://docs.kerne.io/errors
  version: 1.0.0
  contact:
    name: Kerne Team
    url: https://kerne.io
    email: support@kerne.io
  license:
    name: Proprietary
    url: https://kerne.io/license
servers:
  - url: https://api.kerne.io
    description: Production Server
security: []
tags:
  - name: Auth
    description: Authentication endpoints
  - name: Waitlist
    description: Waitlist management
  - name: Invitations
    description: Invitation system
  - name: Billing
    description: 'The tenant''s end users: subscription, entitlements, usage, checkout'
  - name: Pricing
    description: Public pricing page data
paths:
  /v1/auth/passwordless/start:
    post:
      tags:
        - Auth
      summary: Start passwordless login or signup
      description: >-
        Emails a one-click link for the given address. If the email belongs to
        an existing user, it's a login link; otherwise, when registration allows
        it, this creates the account first and the link both confirms the email
        and logs them in. Always responds identically regardless of outcome.
      operationId: AuthController_startPasswordless
      parameters: []
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/PasswordlessStartDto'
      responses:
        '200':
          description: ''
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SuccessMessageDto'
      security:
        - AppIdentifier: []
components:
  schemas:
    PasswordlessStartDto:
      type: object
      properties:
        email:
          type: string
          example: user@example.com
        invitationToken:
          type: string
          description: JWT invitation token received via email
        invitationCode:
          type: string
          description: Short invitation code
      required:
        - email
    SuccessMessageDto:
      type: object
      properties:
        success:
          type: boolean
        message:
          type: string
      required:
        - success
        - message
  securitySchemes:
    AppIdentifier:
      type: apiKey
      in: header
      name: x-app-id
      description: App identifier (App.id, sent as the x-app-id header)

````