> ## 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. > To sign a new merchant up for Fluid programmatically, call POST https://api.fluid.app/api/company with no credentials, as described in /api/agent-signup. Do not automate the signup form or book a demo. The merchant must open the emailed sign-in link and create an API token before authenticated calls are possible. > 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or unversioned operation only when no newer versioned equivalent exists — the company-v0 notes below list the known superseded operations.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. > Navigation menu management is documented in themes/navigation-menus. These unversioned admin endpoints (/api/menus and nested menu_items) are verified against the implementation but are not yet in the synced OpenAPI specs. Use that reference for menu payloads and its flat page/per_page pagination; missing spec coverage does not make these endpoints unavailable. > 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/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/members-v2025-06.yaml covers the v2025-06 unified Member identity surface (/api/v2025-06/members/... paths, bearer-authenticated — member list/create/show/update, lookup by email/username/external_id/legacy_customer_id, member-type assignment, and the sponsor genealogy read). Prefer it over the customers and reps surfaces when the member type matters: /customers does not serialize member_type. 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. # Callbacks > Connect your endpoints to store events such as cart tax, cart shipping and payment redirects, and manage each callback's URL and status. Use the **Callbacks** screen to have Fluid call your endpoint during store events, such as a cart that needs its tax calculated. For most events, the store action waits for your response, so a slow endpoint slows it down. ## Where to find it In the admin, click the **Settings** gear in the top bar. In the Settings sidebar, under **System**, select **Callbacks**. You can also click the **Developer Hub** code icon in the top bar, then select **Callbacks** in the Developer Hub sidebar. If you don't see **Callbacks**, your role doesn't have access to **Developer**. An admin who manages roles can give your role **View only** or **Full access** to **Developer** on the role's **Permissions** tab, in the **Settings** card. See [Roles](/help/admin/settings/roles). ## The callbacks list The list shows your company's callbacks. Click **Create Callback** to add one. * The **All**, **Active** and **Inactive** tabs filter the list by status. **All** is selected when the screen opens. * Sort the list by **Event**, **Status** or **Created At**. The list has these columns: * **Event**: the store event the callback responds to, for example `update_cart_tax`. * **URL**: the endpoint Fluid sends the request to. The list shortens long URLs. Hover over one to see the full address. * **Timeout**: you can ignore this column. Fluid sets the time limit for each event. * **Installed By** * **Status**: **active** or **inactive**. * **Created At**: the date and time the callback was created. Click a row to open the callback, or use its actions menu to **Edit** or **Delete** it. If your role has **View only** for **Developer**, **Create Callback** is hidden and the actions menu has **View** instead. You can open a callback to see its settings, but the panel has no **Save** or **Update** button. Some callbacks in this list may belong to droplets you've installed. Check with your team before you change or delete a callback you didn't create. ## The callback panel The panel opens on the right when you click **Create Callback** or open a callback. * **Definition**: the event that triggers the callback. Select it from the **Definition** menu, which lists event names such as `update_cart_tax`, `update_cart_shipping` and `redirect_cart_payment`. This field is required. * **URL**: the address of your endpoint, for example `https://shop.example.com/fluid/callbacks`. It must start with `https://`. * **Timeout (seconds)**: new callbacks start at 5. Fluid sets the time limit for each event, and this value doesn't change it, so you can leave it as is. * **Active**: turn this on to have the callback receive events. New callbacks start with **Active** on. The panel has a **Cancel** button and a **Save** button, which reads **Update** when you edit an existing callback. Fluid uses a tax callback (`update_cart_tax`) only when your tax settings use **Custom Tax Integration** or **Droplet**, or, in **Per Country** mode, when a country's **Tax Mode** is **Custom Tax Integration** or **Tax Droplet**. You choose this on the [Taxes](/help/admin/settings/taxes) screen. The Taxes screen mentions callback country filters. You can't set them on the **Callbacks** screen. Your developer sets them through the [Fluid API](/api/overview). ## Create a callback On the **Callbacks** screen, click **Create Callback**. The **Create Callback** panel opens. In **Definition**, select the event you want your endpoint to handle. If you already created a callback for this event, edit it instead. In **URL**, enter the address of your endpoint. It must start with `https://`. Leave **Active** on so the callback starts receiving events, then click **Save**. The new callback appears in the list. ## Edit a callback In the list, click the callback, or choose **Edit** from its actions menu. The **Edit Callback** panel opens. Change the fields you need, for example the **URL**, then click **Update**. To pause a callback without deleting it, open it, turn off **Active** and click **Update**. Turn **Active** back on when you're ready to use it again. ## Delete a callback In the list, choose **Delete** from the callback's actions menu. In the **Delete Callback?** dialog, click **Delete**. You can't undo this. ## FAQ A webhook tells your service that something happened, without holding up the store action. A callback calls your service during the event, and for most events Fluid waits for your response before it continues. If you only need to know that an event happened, use [Webhooks](/help/admin/settings/webhooks) instead. Developers can find the callback API alongside webhooks in [Register and handle webhooks](/api/guides/webhooks#related-surfaces). Check these things: * The **URL** must start with `https://`. * You can create only one callback for each event. If you already created a callback for this event, open it and change its **URL** instead. * The `deliver_email` event accepts only one active callback for your company. If another callback for it is already active, such as one a droplet installed, Fluid rejects the save while **Active** is on. When Fluid rejects a save for one of these reasons, the panel closes and an error message appears, so you need to enter your details again. If an error appears under a field instead, the panel stays open. Fix the field and save again. For example, **Timeout (seconds)** must be a number from 1 to 30. If it shows 0, enter a number such as 5. ## Related pages * [Settings](/help/admin/settings) * [Taxes](/help/admin/settings/taxes) * [Communications](/help/admin/settings/communications) * [Webhooks](/help/admin/settings/webhooks) * [Roles](/help/admin/settings/roles) * [Register and handle webhooks](/api/guides/webhooks)