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

# Finish sign-in with an authenticator or backup code

> Completes a sign-in that stopped at the second factor. Takes a six-digit TOTP code or a 10-character backup code (with or without the hyphen) — the server tells them apart by length. A TOTP code can't be replayed and a backup code is spent on use; when one is, `backupCodesRemaining` tells you how many are left. A wrong code is 403, not 401, so the portal doesn't read it as a dead session. An expired pre-auth token is 400. Rate-limited to 10 requests per 15 minutes per IP. Writes LOGIN_TOTP, LOGIN_BACKUP_CODE or LOGIN_2FA_FAILED audit entries.



## OpenAPI

````yaml /api-reference/openapi.yaml post /v1/auth/2fa/code
openapi: 3.1.0
info:
  title: Server.Express API
  version: 1.0.0
  description: >-
    The customer-facing Server.Express API: auth, billing, tickets, cloud and
    dedicated servers, hosting, reselling and account management. Every response
    uses the `{ success, data | error }` envelope.
  contact:
    name: Server.Express
    url: https://server.express
servers:
  - url: https://my.server.express/api
    description: Production
security:
  - bearerAuth: []
  - apiToken: []
tags:
  - name: API Tokens
  - name: Account
  - name: Auth
  - name: Cloud
  - name: Coupons
  - name: Credits
  - name: Dashboard
  - name: Dedicated
  - name: Health
  - name: Hosting
  - name: Integrations
  - name: Invoices
  - name: Livechat
  - name: Notifications
  - name: Passkeys
  - name: Payments
  - name: Products
  - name: Public
  - name: Public Invoices
  - name: Public Tools
  - name: Reseller
  - name: SSH Keys
  - name: Services
  - name: Tasks
  - name: Teams
  - name: Tickets
  - name: Web Hosting
  - name: Webhooks
paths:
  /v1/auth/2fa/code:
    post:
      tags:
        - Auth
      summary: Finish sign-in with an authenticator or backup code
      description: >-
        Completes a sign-in that stopped at the second factor. Takes a six-digit
        TOTP code or a 10-character backup code (with or without the hyphen) —
        the server tells them apart by length. A TOTP code can't be replayed and
        a backup code is spent on use; when one is, `backupCodesRemaining` tells
        you how many are left. A wrong code is 403, not 401, so the portal
        doesn't read it as a dead session. An expired pre-auth token is 400.
        Rate-limited to 10 requests per 15 minutes per IP. Writes LOGIN_TOTP,
        LOGIN_BACKUP_CODE or LOGIN_2FA_FAILED audit entries.
      operationId: publicAuthTwoFactorCode
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
                - preAuthToken
                - code
              properties:
                preAuthToken:
                  type: string
                  description: >-
                    From the `twoFactorRequired` response of login, OAuth
                    exchange or the Telegram Mini App.
                code:
                  type: string
                  description: >-
                    A six-digit authenticator code, or a backup code such as
                    `ABCDE-FGHIJ`.
      responses:
        '200':
          description: Signed in.
          content:
            application/json:
              schema:
                type: object
                required:
                  - success
                  - data
                properties:
                  success:
                    type: boolean
                    const: true
                  data:
                    allOf:
                      - $ref: '#/components/schemas/PublicAuthSession'
                      - type: object
                        properties:
                          backupCodesRemaining:
                            type: integer
                            minimum: 0
                            description: Present only when a backup code was used.
        '400':
          $ref: '#/components/responses/BadRequest'
        '403':
          $ref: '#/components/responses/Forbidden'
        '429':
          $ref: '#/components/responses/TooManyRequests'
        '500':
          $ref: '#/components/responses/ServerError'
      security: []
components:
  schemas:
    PublicAuthSession:
      type: object
      required:
        - accessToken
        - refreshToken
        - user
      properties:
        accessToken:
          type: string
          description: >-
            Access JWT, good for 15 minutes. Send as `Authorization: Bearer
            <token>`.
        refreshToken:
          type: string
          description: >-
            Opaque refresh token (`se_rt_…`), good for 30 days and rotated on
            every use.
        user:
          $ref: '#/components/schemas/PublicAuthSessionUser'
    PublicAuthSessionUser:
      type: object
      required:
        - id
        - email
        - firstName
        - lastName
        - role
      properties:
        id:
          type: string
          format: uuid
        email:
          type: string
          format: email
        firstName:
          type: string
        lastName:
          type: string
        role:
          type: string
          enum:
            - CLIENT
            - ADMIN
    ErrorResponse:
      type: object
      required:
        - success
        - error
      properties:
        success:
          type: boolean
          const: false
        error:
          type: string
          description: Human-readable error message.
      additionalProperties: true
  responses:
    BadRequest:
      description: Validation failed or the request is malformed.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
    Forbidden:
      description: >-
        Authenticated but not allowed (missing scope, not an admin, or not your
        resource).
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
    TooManyRequests:
      description: Rate limit exceeded.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
    ServerError:
      description: Unexpected server error.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT
      description: >-
        Session access token (JWT) from POST /v1/auth/login or /v1/auth/refresh.
        A session satisfies every API scope.
    apiToken:
      type: http
      scheme: bearer
      bearerFormat: se_live_<prefix>_<secret>
      description: >-
        Personal API token created under Settings → API tokens. Only routes
        guarded by verifyApiAuth accept it, and the token must carry the scope
        named in the operation's x-required-scope.

````

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