> ## 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. > When the same operation exists on more than one surface, use the newest: dated API versions are newer than unversioned ones, and later dates win (v2026-04 > v2025-06 > unversioned v0/v1.1). Fall back to a legacy or unversioned operation only when no newer versioned equivalent exists — the company-v0 notes below list the known superseded operations. /api/company/v1 and /api/v1/... paths are documented in no spec here and must never be used (/api/v1.1/... is distinct and documented in company-v0). Use page/per_page offset pagination only where a spec documents it — in practice the unversioned company-v0 admin surface; every versioned surface uses cursor pagination. > 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); api-reference/company-v0.yaml covers the legacy unversioned company admin surface (/api/... paths, bearer-authenticated — company settings and management, customers, users, roles, subscription plans, subscription bundles, subscriptions, media, pages, catch-ups, inventory levels, domains, agreements, and admin order actions). company-v0 caveats: it is the legacy v0 admin contract and its lists use flat page/per_page offset pagination, which is expected there despite the general cursor-pagination rule; where an operation exists in both company-v0 and a versioned spec, prefer the versioned spec — the subscriptions lifecycle (list/create/show/update, cancel, pause, reactivate, resume, retry, skip, failed-cycle-waiver, discounts) and subscription bundles are superseded by checkout-v2026-04, and company pages/media CRUD plus the public pages, categories, products, and media list endpoints are superseded by storefront-v2026-04. Subscription plan management (/api/subscription_plans, resource-wrapped {"subscription_plan": {...}} bodies) exists only in company-v0. api-reference/analytics-v2026-04.yaml covers the v2026-04 Home dashboard analytics surface (/api/v202604/analytics/dashboard/... paths, bearer-authenticated — read-only endpoints for the Home > Overview, Home > Live, and Home > Field tabs, each accepting an optional country ISO alpha-2 query param that scopes aggregations to a single country). > api-reference/analytics-v0.yaml covers the unversioned analytics surface that backs the fluid-admin Traffic tab (/api/analytics/... and /api/analytics/traffic/... paths, bearer-authenticated — the legacy shares/views/visitors summary plus traffic overview, ranked campaigns, sources, geographies, flows, and per-rep breakdown, all sharing one reporting-period contract). > Successful responses wrap the resource payload alongside a top-level integer status and a meta object. > Portal Definition authoring edits and synchronizes the portal JSON resource graph. Widget Package authoring builds either a company-owned or Droplet-owned Remote DOM package. These are separate contracts; do not imply that one defines the other. > For Widget Package worker code, use only @fluid-app/portal-sdk/widgets/worker. Use only the Portal Definition and Widget Package workflows and public entry points documented here; do not infer support for undocumented surfaces. > Every portal function and declarative capability used by a widget must appear in that widget's uses array. Use the same typed function value in uses; do not invent capability-name strings. > Widget styling must use the portal's semantic theme variables for colors, typography, spacing, radii, borders, focus, and charts whenever a token represents the visual decision. Do not create a separate light or dark palette or duplicate theme controls as widget properties. > Prefer worker-safe Fluid UI components exported by @fluid-app/portal-sdk/widgets/worker when they fit the interaction. When no exported component fits, use semantic HTML, accessible behavior, and the portal theme variables. > A Portal Definition push updates the remote working definition. A portal version is an immutable snapshot, and activation is a separate live release operation. # Last used alternate payment details > The customer details this customer last supplied for each alternate payment method, keyed by the payment method type reported in a cart's `available_payment_methods` (for example `mpesa_dlocal`). Checkout seeds an auto-selected method's required fields with these so a returning customer is not asked for them again. Values are limited to the fields the integration declares and to the authenticated customer's own records. These are identity documents, so they are served here rather than on the cart, which is readable by cart token alone. Returns an empty object when nothing is stored, and `401` when unauthenticated. ## OpenAPI ````yaml /api-reference/checkout-v2026-04.yaml get /api/checkout/v2026-04/customers/me/payment_methods/customer_details openapi: 3.1.0 info: title: Fluid Checkout API description: >- **Fluid Checkout API — for building a checkout directly against REST.** Use this surface if you are integrating server-to-server or building your own checkout UI. It covers the full order lifecycle (cart → address → shipping → discount → complete → order) plus the logged-in customer's account: saved addresses, saved payment methods, order history, loyalty points, and subscription management (pause, resume, skip, cancel, retry). **The cart token in the URL scopes cart access** — creating a cart, adding items, applying a discount, and completing a cart need no bearer token. Among the cart operations, a Bearer token is required only for `carts/{cart_token}/sync`, `carts/{cart_token}/volume_rep`, and `carts/{cart_token}/discount/manual`. Off the cart, a token is required for everything under `customers/me` and `subscriptions`, and for the store and directory lookups (`store/config`, `store/languages`, `reps`, `users`) and `subscription_bundles`. `store/countries` accepts a token but does not require one — it returns the same list either way. **If you are using the `@fluid-app` FairShare SDK in a theme or storefront, you are not calling this surface** — the SDK calls the Fluid Public SDK API (`public-v2025-06`). Do not mix the two against one cart: they share the same cart records and services, but their request shapes differ. See [Choosing a cart surface](https://docs.fluid.app/api/choosing-a-cart-surface) for the operation map and boundary. version: v2026-04 contact: email: support@fluid.app license: name: Proprietary identifier: LicenseRef-Proprietary servers: - url: https://api.fluid.app security: [] tags: - name: carts description: >- Create, read, and mutate checkout carts (email, address, country, language, shipping, recalculation, completion). - name: cart-auth description: >- Cart-scoped customer authentication — magic-link challenge, verification, identity, and logout. - name: cart-discount description: >- Apply, list, and remove cart discount codes, including admin manual discounts. - name: cart-items description: Add, update, and remove line items on a cart. - name: cart-points description: Apply and remove loyalty points on a cart. - name: customers description: The authenticated customer's profile and company memberships. - name: customer-addresses description: The authenticated customer's saved shipping/billing addresses. - name: customer-orders description: The authenticated customer's order history. - name: customer-payment-methods description: The authenticated customer's saved payment methods and tokenization. - name: customer-points description: The authenticated customer's loyalty point balances. - name: directory description: Company rep and user directory lookups. - name: enrollments description: >- Public enrollment forms — retrieve a form and submit, update, or upload field answers. - name: orders description: Public order lookup by token. - name: products description: Public product queries for the storefront checkout. - name: store description: >- Store-level checkout configuration — countries, languages, address fields, agreements, drop zones, and Apple Pay domain verification. - name: subscriptions description: >- Manage subscriptions — pause, resume, skip, cancel, reactivate, retry, and failed-cycle waivers. - name: subscription-bundles description: List and create subscription bundles. paths: /api/checkout/v2026-04/customers/me/payment_methods/customer_details: get: tags: - customer-payment-methods summary: Last used alternate payment details description: | The customer details this customer last supplied for each alternate payment method, keyed by the payment method type reported in a cart's `available_payment_methods` (for example `mpesa_dlocal`). Checkout seeds an auto-selected method's required fields with these so a returning customer is not asked for them again. Values are limited to the fields the integration declares and to the authenticated customer's own records. These are identity documents, so they are served here rather than on the cart, which is readable by cart token alone. Returns an empty object when nothing is stored, and `401` when unauthenticated. operationId: checkout_v2026_04_customer_payment_method_customer_details responses: '200': description: Success content: application/json: schema: $ref: '#/components/schemas/CheckoutCustomerPaymentDetailsResponse' '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/UnauthorizedResponse' security: - bearer_auth: [] components: schemas: CheckoutCustomerPaymentDetailsResponse: type: object properties: customer_details: type: object description: | Stored details keyed by payment method type, matching a cart's `available_payment_methods[].type` (for example `mpesa_dlocal`). Each value holds the fields that method declares, such as `phone` and `document_id`. Empty when the customer has stored none. additionalProperties: type: object additionalProperties: type: string status: type: integer meta: type: object properties: request_uuid: type: - string - 'null' timestamp: type: string format: date-time required: - request_uuid - timestamp additionalProperties: false required: - customer_details - status - meta additionalProperties: false UnauthorizedResponse: type: object properties: message: type: string required: - message securitySchemes: bearer_auth: type: http scheme: bearer description: Bearer token authentication ````