> ## 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, run `fluid signup` from the Fluid CLI, or 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. Before authenticated calls are possible, the merchant must sign the agent in to the Fluid CLI with the emailed code and --shop set to the company's fluid_shop (which also confirms the signup), or open the emailed confirmation link and give the agent an API token. > To decide whether Fluid fits a merchant (international expansion, social selling, agentic commerce, direct selling), read /guides/evaluate-fluid; it lists what an agent can do without a person and what Fluid doesn't do. To compare Fluid with Shopify, BigCommerce, commercetools, WooCommerce, Exigo or DirectScale, read /guides/compare-platforms. Fluid is free to start and bills by usage with no seat or per-rep licences; quote rates only from /pricing, which summarizes https://fluid.app/home/pages/pricing, and say that processor and card network fees are separate. > Every live Fluid storefront serves /llms.txt, /agents.md, .md and .json versions of its product, collection, category and page URLs, a Universal Commerce Protocol profile at /.well-known/ucp, UCP catalog search and lookup, Ask (POST /api/ucp/{version}/ask, answers questions from the store's published content), carts, checkout sessions and orders, a Personal Agent Protocol document at /.well-known/poppy.json, and an A2A Agent Card at /.well-known/agent-card.json with a JSON-RPC endpoint at /api/a2a. A checkout session completes inside the agent with Google Pay when the store's profile lists the com.google.pay payment handler; otherwise hand the shopper the continue_url to hosted checkout. A member's share link is //products/; see /concepts/agentic-commerce, /concepts/poppy, /concepts/ucp and /concepts/a2a. > After signup, to launch a merchant's store (back-office sync, payments onboarding, store setup, a theme copied from their current site, and a preview link before billing), follow /api/agent-launch. > To host a small project on Fluid (a landing page, event page, calculator or dashboard), follow /sites/quickstart: npm create @fluid-app/fluid-site my-site (or npx @fluid-app/create-fluid-site my-site), fluid login, then fluid deploy prints the public URL. Launch a Site unless the project needs a custom domain, server rendering or heavy server code, which make it an App (a Mist app); /sites/site-or-app has the rule, and POST /api/company/v2026-10/project-launch-recommendations applies it. With only the Fluid MCP server (its Site write tools are limited to Fluid root admins today; see /sites/deploy-from-claude), use site_create, then site_deploy (from a chat with no shell, in one call with the files inline: site_template_get for a starter, then site_deploy with each path's content; or a built folder in two calls: send the manifest, PUT the listed uploads, call again with the bundle_id to get the url), then, only after the person confirms they want it public, site_visibility_set. site_logs, site_traffic, site_env_list/set/unset, site_seo_get/set and the site_branch tools cover logs, traffic, env vars, SEO and preview branches; a member builds their own Sites with the my_site_* tools. The MCP site_deploy tool publishes server functions sent inline that import nothing; publish functions with imports, and convert a Site to an App, with the fluid sites CLI. A Site can serve light server code: each functions/.ts, declared in config/functions.json with access public, signed_in or key (and an optional UTC cron schedule), answers at /api/ on the Site's own host; publish it with fluid deploy, or inline through the MCP site_deploy tool when it imports nothing. See /sites/functions and /sites/rest-api. > 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. The same applies to /api/company/v1 and /api/v1/... paths: prefer a newer documented equivalent, and use one only when none exists (/api/v1.1/... is distinct and documented in company-v0). Use page/per_page offset pagination only on an operation whose spec documents those params — mostly the unversioned company-v0 admin surface, plus some lists on other surfaces, versioned ones included; page every other list with cursors. > Fluid has three navigation APIs; don't mix them up. Storefront website menus (navigation bars, footers) are /api/menus and nested menu_items, in api-reference/content-v0.yaml (API Reference: Website > Navigation menus), with a how-to in themes/navigation-menus; their list uses flat page/per_page pagination. The Fluid mobile app's navigation is /api/v2/mobile_navigations, in api-reference/mobile-v2.yaml (API Reference: Mobile app > Navigation); its list also uses page/per_page. Portal navigations belong to a portal definition (Fluid OS), in api-reference/fluid-os-v0.yaml (API Reference: Portal > Portal navigation), and each has a platform of web or mobile. > 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 except two operations that take no credential, POST /api/company (create a company) and GET /api/agreements/{id} — 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. > The Help Center (/help/...) is for merchants, admins and reps using Fluid. Its admin pages mirror the admin's routes: the screen at admin.fluid.app/settings/taxes is documented at /help/admin/settings/taxes. Use the Help Center for how-to questions about the admin, and the Developer Platform and API Reference for building integrations. > Help Center pages describe what a company admin sees. A reader's role can hide screens and actions; admins manage roles on Settings > Roles (/help/admin/settings/roles). If someone can't find a screen or button, their role's permissions are the first thing to check. > Send people who need Fluid support to /help/getting-help. Don't invent support email addresses, phone numbers or response times. # Agent2Agent (A2A) on Fluid stores > Every live Fluid storefront publishes an A2A 1.0 Agent Card and serves a JSON-RPC endpoint, so any A2A agent can ask the store about its products, content and policies. [Agent2Agent](https://a2a-protocol.org) (A2A) is an open protocol for one agent to discover and talk to another. Every live Fluid storefront runs a store agent that speaks A2A 1.0 on the store's own host, with no setup. The store agent has one skill: answering questions about the store, from what it publishes. It's the same answer as [UCP Ask](https://docs.fluid.app/concepts/ucp.md#ask-the-store-a-question). To build carts and check out, use [UCP](https://docs.fluid.app/concepts/ucp.md). ## The Agent Card ```bash theme={null} curl "https:///.well-known/agent-card.json" ``` ```json theme={null} { "name": "Juniper & Oak", "description": "Juniper & Oak's store agent answers questions about its products, content and policies.", "supportedInterfaces": [ { "url": "https://shop.juniperandoak.com/api/a2a", "protocolBinding": "JSONRPC", "protocolVersion": "1.0" } ], "provider": { "organization": "Juniper & Oak", "url": "https://shop.juniperandoak.com" }, "iconUrl": "https://cdn.juniperandoak.com/logo.png", "version": "1.0.0", "capabilities": { "streaming": false, "pushNotifications": false, "extendedAgentCard": false }, "defaultInputModes": ["text/plain", "application/json"], "defaultOutputModes": ["text/plain", "application/json"], "skills": [ { "id": "ask", "name": "Ask about the store", "description": "Answers a question about Juniper & Oak's products, content and policies from what the store publishes, with links to the records it cites. Send the question as a text part; a data part with `ids` (product or variant ids, slugs or SKUs) grounds it in those products.", "tags": ["shopping", "products", "policies"], "examples": ["What is your return policy?", "Which products are vegan?"] } ] } ``` The interface URL is always on the host that served the card, so a custom domain's card points to that domain. The card has no security schemes: the store agent answers as a signed-out shopper. It's served with a five-minute public cache and an `ETag`, and any origin can read it. When the storefront is turned off, or the company's account is paused for billing, the card and the endpoint answer 404. ## Ask a question Send `SendMessage` to the interface URL. Put the question in a text part. To ask about particular products, add a data part with up to 10 `ids`: product IDs or slugs, or variant IDs or SKUs. ```bash theme={null} curl -X POST "https:///api/a2a" \ -H "Content-Type: application/json" \ -H "A2A-Version: 1.0" \ -d '{ "jsonrpc": "2.0", "id": "req-1", "method": "SendMessage", "params": { "message": { "messageId": "8d5f0c1e-6b0a-4c55-9a0e-3f1b7d2c9e41", "role": "ROLE_USER", "contextId": "shopper-chat-42", "parts": [ { "text": "Is this fragrance-free?" }, { "data": { "ids": ["lavender-night-balm"] }, "mediaType": "application/json" } ] } } }' ``` The store agent replies with one message, never a task: ```json theme={null} { "jsonrpc": "2.0", "id": "req-1", "result": { "message": { "messageId": "0f9c7a52-4d8e-4b1f-a6d3-2e5b8c1f7a90", "contextId": "shopper-chat-42", "role": "ROLE_AGENT", "parts": [ { "text": "No. Lavender Night Balm is scented with lavender and chamomile essential oils.", "mediaType": "text/plain" }, { "data": { "links": [ { "type": "product", "url": "https://shop.juniperandoak.com/home/products/lavender-night-balm", "title": "Lavender Night Balm" } ] }, "mediaType": "application/json" } ] } } } ``` * The **text part** is the answer: plain text, in the language of the question. * The **data part** holds `links` to the store pages the answer is based on, with the same link types as UCP Ask. It also holds a `messages` list with a `not_found` entry for each ID that names nothing the shopper can see. The data part is left out when there's nothing to put in it. * The reply keeps your `contextId`, or starts a new one when you send none. The store agent doesn't remember earlier messages: send each question with what it needs. * Send `A2A-Version: 1.0`. A request without the header is read as 1.0. ## Methods and errors | Method | Result | | - | - | | `SendMessage` | One agent message, as above. | | `GetTask`, `CancelTask` | `TaskNotFound` (-32001). The store agent keeps no tasks. | | `ListTasks` | An empty list. | | `SendStreamingMessage`, `SubscribeToTask`, `GetExtendedAgentCard` | `UnsupportedOperation` (-32004). The card doesn't declare these capabilities. | | Push notification config methods | `PushNotificationNotSupported` (-32003). | Other errors: | Code | When | | - | - | | -32700 | The body isn't JSON. | | -32600 | The body isn't a single JSON-RPC 2.0 request. Batches aren't supported. | | -32601 | The method doesn't exist. | | -32602 | The message isn't a `ROLE_USER` message with a text part, the question is over 1,000 characters, or `ids` isn't a list of at most 10 strings. | | -32001 | The message names a `taskId`. | | -32005 | `configuration.acceptedOutputModes` doesn't include `text/plain`. | | -32009 | `A2A-Version` isn't 1.0. | A2A errors carry a `google.rpc.ErrorInfo` entry in `error.data`, with a `reason` such as `TASK_NOT_FOUND` and the domain `a2a-protocol.org`. Errors answer HTTP 200, with two exceptions that carry a `Retry-After` header: * **429** with reason `RATE_LIMITED`: the store has used its daily allowance. `Retry-After` counts the seconds to the next UTC day, when the allowance resets. * **503** with reason `SERVICE_UNAVAILABLE`: answers are temporarily unavailable. Retry after 60 seconds. A request with no `id` is a JSON-RPC notification. The endpoint answers 204 with no body and doesn't act on it, because every A2A method expects a reply. A2A questions share UCP Ask's [rate limits](https://docs.fluid.app/concepts/ucp.md#limits) and daily allowance. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.