> ## 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. # We-Commerce Checkout: High-Converting One-Page Checkout > Fluid Checkout at checkout.fluid.app handles payments, shipping, tax, and rep attribution on one page, with saved profiles to boost conversions. Fluid Checkout is a hosted, one-page checkout experience that handles every step of the purchase process — address validation, shipping calculation, tax, inventory, discounts, and payment — without requiring you to build or maintain checkout infrastructure. Because it is purpose-built for We-Commerce, every order processed through Fluid Checkout carries full FairShare attribution data, so the right rep always gets credit regardless of how the buyer arrived at the cart. ## Key Features **Hosted at `checkout.fluid.app`** — Fluid runs and scales the checkout infrastructure for you. There are no servers to provision, no PCI compliance scope to manage on your side, and no checkout code to keep up to date. You embed or link to the checkout, and Fluid handles the rest. **One-page checkout with saved profiles** — The entire purchase flow — contact details, shipping address, payment method — lives on a single page. Returning customers with a Fluid Pay profile can pre-fill all their details automatically, eliminating the friction that causes cart abandonment. First-time buyers are prompted to save their details for future purchases at the end of the flow. **Built-in operational features** — Address validation, real-time shipping rate calculation, tax computation, inventory checks, and discount code redemption are all handled by Fluid Checkout out of the box. You configure your shipping carriers, tax rules, and inventory in your Fluid dashboard; the checkout enforces them automatically on every order. **Full FairShare attribution** — Checkout reads attribution data written by the FairShare SDK and records it against every order. Commission rules are evaluated at the moment the order is placed, so there is no post-purchase reconciliation step and no attribution disputes. **300+ alternative payment methods in 100+ countries** — Fluid Payments powers the checkout's payment layer. Buyers can pay with the local methods they prefer — bank transfers, digital wallets, buy-now-pay-later — without any additional integration work on your part. ## How to Customise Your Checkout Fluid Checkout is designed to be extended without forking or modifying the underlying checkout code. Use the following mechanisms to tailor the experience to your brand and business logic. ### Droplets [Droplets](/concepts/droplets) are third-party integrations that can embed their own UI inside the checkout at specific Drop Zone locations. Install a Droplet from the [Droplet Marketplace](https://admin.fluid.app/droplets) to add loyalty point displays, upsell widgets, gift message fields, or any other functionality a Droplet provides. ### Drop Zones Drop Zones let you embed external UI in configured checkout and order-confirmation locations. See [Embed apps with drop zones](/api/guides/drop-zones) for the available integration surfaces. For a direct REST integration, use [List drop zones](/api-reference/store/list-drop-zones). ### Webhooks Fluid Checkout emits events you can subscribe to so your systems stay in sync with buyer activity: * **`cart_updated`** — Fired whenever a buyer modifies their cart: adding or removing items, applying a discount code, or changing a quantity. Use this to update inventory holds or trigger personalisation logic. * **`cart_abandoned`** — Fired when a buyer leaves the checkout without completing their purchase. Use this to trigger recovery emails, retargeting campaigns, or rep follow-up tasks. Subscribe to these events from your Fluid dashboard or by following the [Webhooks guide](/api/guides/webhooks). ### Middleware For advanced use cases — custom discount engines, dynamic product bundling, or complex B2B pricing rules — Fluid supports middleware hooks that intercept cart operations before the checkout applies its standard logic. Contact your Fluid account team to discuss middleware configuration for your account. Fluid Pay has over 2 million payment-ready customers with saved profiles from previous purchases across the Fluid network. When one of these customers reaches your checkout, their address and payment method are pre-filled automatically, letting them complete their order in a single click — no separate fast-checkout integration required. ## Next Steps