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

# Challenge Hub Handoff

> Register this hub browser for a launch; carries no Contact authority.

Sets an HttpOnly nonce cookie and stores only hashes of the nonce, the
state and the S256 code challenge.



## OpenAPI

````yaml /openapi/mio-openapi.json post /api/v1/contact-auth/handoff/challenges
openapi: 3.1.0
info:
  description: >-
    Production API reference for Membership.io. Use the authored guides for
    workflows and the generated endpoint pages for exact parameters and schemas.
  title: Membership.io API
  version: 0.1.0
servers:
  - description: Production
    url: https://api.member.dev
security:
  - bearerAuth: []
paths:
  /api/v1/contact-auth/handoff/challenges:
    post:
      tags:
        - contact-auth
      summary: Challenge Hub Handoff
      description: |-
        Register this hub browser for a launch; carries no Contact authority.

        Sets an HttpOnly nonce cookie and stores only hashes of the nonce, the
        state and the S256 code challenge.
      operationId: contact_auth.post_contact_auth_post_contact_auth_handoff_challenges
      requestBody:
        content:
          application/vnd.api+json:
            schema:
              $ref: '#/components/schemas/HubHandoffChallengeEnvelope'
        required: true
      responses:
        '201':
          content:
            application/vnd.api+json:
              schema:
                $ref: '#/components/schemas/HubHandoffChallengeResponse'
          description: Successful Response
        '422':
          content:
            application/vnd.api+json:
              schema:
                $ref: '#/components/schemas/HTTPValidationError'
          description: Validation Error
components:
  schemas:
    HubHandoffChallengeEnvelope:
      additionalProperties: false
      properties:
        data:
          $ref: '#/components/schemas/HubHandoffChallengeRequestResource'
      required:
        - data
      title: HubHandoffChallengeEnvelope
      type: object
    HubHandoffChallengeResponse:
      additionalProperties: false
      properties:
        data:
          $ref: '#/components/schemas/HubHandoffChallengeResource'
      required:
        - data
      title: HubHandoffChallengeResponse
      type: object
    HTTPValidationError:
      properties:
        detail:
          items:
            $ref: '#/components/schemas/ValidationError'
          title: Detail
          type: array
      title: HTTPValidationError
      type: object
    HubHandoffChallengeRequestResource:
      additionalProperties: false
      properties:
        attributes:
          $ref: '#/components/schemas/_HubHandoffChallengeRequestAttributes'
        type:
          const: hub_handoff_challenges
          title: Type
          type: string
      required:
        - type
        - attributes
      title: HubHandoffChallengeRequestResource
      type: object
    HubHandoffChallengeResource:
      additionalProperties: false
      properties:
        attributes:
          $ref: '#/components/schemas/HubHandoffChallengeAttributes'
        id:
          title: Id
          type: string
        type:
          const: hub_handoff_challenges
          default: hub_handoff_challenges
          title: Type
          type: string
      required:
        - id
        - attributes
      title: HubHandoffChallengeResource
      type: object
    ValidationError:
      properties:
        ctx:
          title: Context
          type: object
        input:
          title: Input
        loc:
          items:
            anyOf:
              - type: string
              - type: integer
          title: Location
          type: array
        msg:
          title: Message
          type: string
        type:
          title: Error Type
          type: string
      required:
        - loc
        - msg
        - type
      title: ValidationError
      type: object
    _HubHandoffChallengeRequestAttributes:
      additionalProperties: false
      properties:
        code_challenge:
          description: >-
            base64url(SHA-256(code_verifier)); the verifier never leaves the hub
            tab.
          pattern: ^[A-Za-z0-9_-]{43}$
          title: Code Challenge
          type: string
        code_challenge_method:
          const: S256
          title: Code Challenge Method
          type: string
        launch_id:
          pattern: ^[A-Za-z0-9_-]{43}$
          title: Launch Id
          type: string
        state:
          pattern: ^[A-Za-z0-9_-]{43}$
          title: State
          type: string
      required:
        - launch_id
        - code_challenge
        - code_challenge_method
        - state
      title: _HubHandoffChallengeRequestAttributes
      type: object
    HubHandoffChallengeAttributes:
      additionalProperties: false
      properties:
        authorize_url:
          description: Admin authorize page; ids travel in the fragment.
          title: Authorize Url
          type: string
        deadline:
          format: date-time
          title: Deadline
          type: string
        hub_slug:
          title: Hub Slug
          type: string
        purpose:
          enum:
            - view
            - preview
          title: Purpose
          type: string
        request_id:
          description: Key for the hub tab's stored verifier and state.
          title: Request Id
          type: string
      required:
        - request_id
        - authorize_url
        - deadline
        - hub_slug
        - purpose
      title: HubHandoffChallengeAttributes
      type: object
  securitySchemes:
    bearerAuth:
      bearerFormat: JWT or mio_sk API key
      description: >-
        Send platform JWTs, contact JWTs, or team API keys as `Authorization:
        Bearer <token>`.
      scheme: bearer
      type: http

````

This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.