> ## Documentation Index > Fetch the complete documentation index at: https://docs.fluid.app/llms.txt > Use this file to discover all available pages before exploring further. > ## Agent Instructions > For new direct REST integrations, use the v2026-04 surfaces. The @fluid-app FairShare SDK continues to use its own published public-v2025-06 contract. > Authenticate with the header Authorization: Bearer ; public storefront read endpoints require no auth. > Lists use cursor pagination via the page[cursor] and page[limit] query params; follow meta.pagination.next_cursor until it is null. > Never use /api/company/v1 or /api/v1 paths, page/per_page params, or offset pagination — they are legacy. > The OpenAPI specs under api-reference/ are the authoritative contracts; prefer them over prose when in doubt. api-reference/storefront-v2026-04.yaml covers the v2026-04 storefront surface (/api/v202604/... paths); api-reference/auth-v0.yaml covers the unversioned auth surface (/api/... paths — authentication, MFA, social auth, and token exchange); api-reference/checkout-v2026-04.yaml covers the v2026-04 checkout surface (/api/checkout/v2026-04/... paths — carts, cart auth, discounts, items, subscriptions, orders, enrollments, and store config); api-reference/public-v2025-06.yaml covers the Public SDK surface used by the @fluid-app FairShare SDK, including its parallel cart lifecycle, browser integrations, versioned payment callbacks, unversioned public utilities, and the cart price-override operation; api-reference/payment-v2026-04.yaml covers the v2026-04 payment gateway admin surface (/api/payment/v2026-04/... paths, bearer-authenticated — gateway CRUD, gateway purchase/authorize/$0-verify, transaction list/show and capture/void/credit, and merchant payment configuration); api-reference/payments-v2026-04.yaml covers the v2026-04 cart payment surface (/api/payments/v2026-04/carts/{cart_token}/... paths, authenticated by the cart token in the path with no bearer — payment-method selection, VGS card tokenization, 3D Secure verification, and PayPal/Braintree/Klarna/Apple Pay flows); api-reference/commerce-v2026-04.yaml covers the v2026-04 commerce order-editing surface (/api/v202604/orders/{order_id}/edits paths, bearer-authenticated — post-checkout order edits that atomically insert items and add adjustments/discounts, with an optional dry-run preview); api-reference/webhooks-v0.yaml covers the unversioned webhooks surface (/api/... paths — webhook registration, delivery payloads, callback registrations, company events, and webhook/callback schemas). > Successful responses wrap the resource payload alongside a top-level integer status and a meta object. # Link Apple account > Link an Apple account to the authenticated user. ## OpenAPI ````yaml /api-reference/auth-v0.yaml post /api/social_auth/link_apple openapi: 3.1.0 info: title: Fluid Auth API version: v0 description: >- Authentication, MFA, social auth, impersonation, and token exchange endpoints. contact: email: support@fluid.app license: name: Proprietary identifier: LicenseRef-Proprietary servers: - url: https://api.fluid.app - url: https://{company}.fluid.app description: Production server with company subdomain variables: company: default: myco description: Company subdomain security: [] tags: - name: auth-token description: Short-lived auth-token minting for the current user company. - name: authentication description: >- Email MFA login, company switching, JWT-based "me" lookups, and public company branding. - name: confirm-visitor description: Visitor token confirmation. - name: impersonation description: Root-admin company impersonation (start and exit). - name: multi-factor-authentications description: MFA record creation and verification-code checks. - name: single-sign-ons description: SSO-flow aliases of the authentication MFA and lookup endpoints. - name: social-auth description: >- Google, Facebook, and Apple OAuth URLs, callback handling, and Apple account linking. - name: switch-role description: Switch the current admin user between admin and rep roles. - name: token-exchange description: Exchange and refresh JWTs and user-company tokens. paths: /api/social_auth/link_apple: post: tags: - social-auth summary: Link Apple account description: Link an Apple account to the authenticated user. operationId: auth_v0_social_auth_link_apple requestBody: required: false description: >- Provide exactly one Apple identifier. `sub` is an alias for `apple_external_id`; `id_token` is decoded to extract its `sub` claim. content: application/json: schema: type: object properties: apple_external_id: type: string sub: type: string description: Alias for apple_external_id. id_token: type: string description: Apple ID token; decoded to extract the sub claim. examples: by_apple_external_id: summary: Link using the Apple subject identifier value: apple_external_id: 001234.abcd5678ef901234.5678 by_id_token: summary: Link using an Apple ID token (sub is decoded from it) value: id_token: eyJraWQiOiJmaDZCcyJ9.eyJzdWIiOiIwMDEyMzQuYWJjZCJ9.Ab12Cd responses: '200': description: Success content: application/json: schema: type: object additionalProperties: false required: - apple_external_id properties: apple_external_id: type: string meta: $ref: '#/components/schemas/Meta' '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/UnauthorizedResponse' '403': description: >- Authenticated principal is a service token, not a user-company member allowed to link an Apple account. content: application/json: schema: $ref: '#/components/schemas/StandardErrorResponse' '409': description: The Apple ID is already linked to a different account. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '422': description: >- No Apple identifier could be resolved, or the user already has a different Apple ID linked. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' security: - bearer_auth: [] components: schemas: Meta: type: object properties: request_id: description: > Opaque per-request identifier echoed on the response; `null` when the request was not assigned one. Quote it when reporting an issue so support can correlate server-side logs. type: - string - 'null' timestamp: description: Server time the response was generated, as an ISO 8601 date-time. type: string format: date-time UnauthorizedResponse: type: object additionalProperties: false required: - message properties: message: description: > Reason the request was rejected as unauthenticated. `401` bodies are this bare `{ "message": "..." }` object rather than the wrapped `ErrorResponse` envelope used by `404`/`422`. type: string StandardErrorResponse: description: >- Common legacy error response envelope. Older endpoints may return one or more of these fields depending on the controller path. type: object properties: message: description: >- Single human-readable error string; the form some legacy controllers (and `401` responses) return. type: string error: $ref: '#/components/schemas/ErrorMessage' description: >- Alternative single-error field (string or structured); present on some legacy controller paths instead of `message`. error_message: $ref: '#/components/schemas/ErrorMessage' description: >- Human-readable summary, mirroring the `error_message` of the newer `ErrorResponse` envelope. errors: $ref: '#/components/schemas/ErrorBag' description: >- Structured per-field or per-issue error detail; shape varies (see `ErrorBag`). meta: $ref: '#/components/schemas/Meta' description: Response metadata (request id and generation timestamp). additionalProperties: $ref: '#/components/schemas/JsonValue' ErrorResponse: type: object additionalProperties: false required: - error_message - errors - meta properties: error_message: description: >- Human-readable summary of what went wrong, safe to surface to the caller. type: string errors: $ref: '#/components/schemas/ErrorBag' description: >- Structured per-field or per-issue detail behind `error_message`; shape varies (see `ErrorBag`) and is `null` when no structured detail is available. meta: $ref: '#/components/schemas/Meta' description: Response metadata (request id and generation timestamp). ErrorMessage: description: An API error message represented as text or structured JSON. anyOf: - type: string - $ref: '#/components/schemas/ErrorBag' - type: 'null' ErrorBag: description: >- Validation errors keyed by field, a list of errors, a single error message, or null when no structured error details are available. anyOf: - type: string - type: array items: $ref: '#/components/schemas/ErrorValue' - type: object additionalProperties: $ref: '#/components/schemas/ErrorValue' - type: 'null' JsonValue: description: >- Any valid JSON value for provider, integration, theme, metadata, or other dynamic payloads whose keys are not fixed by the API contract. anyOf: - type: string - type: number - type: boolean - type: 'null' - type: array items: $ref: '#/components/schemas/JsonValue' - type: object additionalProperties: $ref: '#/components/schemas/JsonValue' ErrorValue: description: A validation or API error value. anyOf: - type: string - type: array items: type: string - type: object additionalProperties: $ref: '#/components/schemas/JsonValue' securitySchemes: bearer_auth: type: http scheme: bearer description: Bearer token authentication (JWT or user-company token) ````