> ## Documentation Index > Fetch the complete documentation index at: https://docs.supercycle.com/llms.txt > Use this file to discover all available pages before exploring further. # Intent > Create an intent for a rental option. Returns the form attributes required to turn a line item into a Cycle when added to the cart. Each rental method (subscription, membership, calendar, resale) stores its options in a product metafield. Every option has a `global_id` that is passed to this endpoint. | Metafield | Method | | ---------------------------------------------------------- | ------------ | | `product.metafields.supercycle.calendar_configuration` | Calendar | | `product.metafields.supercycle.subscription_configuration` | Subscription | | `product.metafields.supercycle.membership_configuration` | Membership | | `product.metafields.supercycle.resale_configuration` | Resale | The options array within each metafield contains a `global_id` for each option: ```json theme={null} { "rental_periods": [ { "global_id": "gid://supercycle/CalendarRental::RentalPeriod/1" }, { "global_id": "gid://supercycle/CalendarRental::RentalPeriod/2" } ] } ``` Once you have the variant ID and option `global_id`, call this endpoint to get the attributes that need to be attached to the line item so Supercycle processes it as a Cycle. The response `attributes` object contains key-value pairs that must be included when submitting the add-to-cart form. Each entry should be added as a hidden input on the product form, or included in the request body when submitting via AJAX. See [Cycle line item property](/developers/line-items/cycle-line-item-properties) and [Validations line item property](/developers/line-items/validations-line-item-property) for the full schema. **Hidden inputs:** ```js theme={null} Object.entries(intent.attributes).forEach(([name, value]) => { const input = document.createElement("input"); input.type = "hidden"; input.name = name; input.value = value; addToCartForm.appendChild(input); }); ``` **AJAX (fetch):** ```js theme={null} const formData = new FormData(addToCartForm); Object.entries(intent.attributes).forEach(([name, value]) => { formData.set(name, value); }); await fetch("/cart/add.js", { method: "POST", body: formData }); ``` ## Add-ons `add_ons` are additional variants that must be submitted in the same request using Shopify's [multiple items cart API](https://shopify.dev/docs/api/ajax/reference/cart#post-locale-cart-add-js) format. Each add-on property (except `cart_quantity`) should be included as `items[n][property]`: ```js theme={null} // Example for a single add-on // items[0][id] = 4321 // items[0][quantity] = 1 // items[0][selling_plan] = 1234 intent.add_ons.forEach(({ cart_quantity, ...addOnAttributes }, index) => { Object.entries(addOnAttributes).forEach(([key, value]) => { formData.set(`items[${index}][${key}]`, value); }); }); ``` `cart_quantity` is not submitted — it is the maximum total quantity of that variant that should be present in the cart. Before adding the add-on, check the current cart to see if the variant is already there and skip if the quantity would exceed `cart_quantity`. ## OpenAPI ````yaml POST /{proxy_path_prefix}/intents openapi: 3.0.3 info: title: Product Availability and Rental Intent API version: 1.0.0 description: >- API for checking product availability and managing rental intents in a customer portal via Shopify proxy servers: [] security: [] paths: /{proxy_path_prefix}/intents: parameters: - name: proxy_path_prefix in: path required: true schema: type: string description: >- The Shopify proxy path prefix configured for the app (e.g., 'customer_portal') post: tags: - Rental Intent summary: Create an intent description: >- Creates an intent for a rental option. Returns attributes to be submitted with the Shopify cart form and any add-on variants that should also be added to the cart. operationId: createIntent requestBody: required: true content: application/json: schema: type: object properties: variant_id: type: integer description: Shopify ID of the variant to create an intent for option: type: object properties: global_id: type: string description: >- Global ID of the rental option (e.g., 'gid://supercycle/CalendarRental::RentalPeriod/1') params: type: object properties: rental_start: type: string format: date description: >- Date when the customer wants to receive the item (required for Calendar, optional for Subscription) location_id: type: integer description: >- Optional Shopify location ID to filter available items by location delivery_method_type: type: string description: Delivery method type (defaults to 'shipping') additionalProperties: true required: - global_id required: - variant_id - option examples: calendar: summary: Calendar intent value: variant_id: 123456789 option: global_id: gid://supercycle/CalendarRental::RentalPeriod/1 params: rental_start: '2025-01-01' subscription: summary: Subscription intent value: variant_id: 123456789 option: global_id: gid://supercycle/SubscriptionRental::PricingGroup/1 params: rental_start: '2025-01-01' membership: summary: Membership intent value: variant_id: 123456789 option: global_id: gid://supercycle/MembershipRental::VariantConfig/1 resale: summary: Resale intent value: variant_id: 123456789 option: global_id: gid://supercycle/ResaleRental::ResaleOption/1 responses: '200': description: Successful response with intent attributes and add-ons content: application/json: schema: type: object properties: attributes: type: object description: >- Key-value pairs to be submitted with the Shopify add-to-cart form. Includes line item properties (keys prefixed with `properties[...]`) and a `selling_plan` ID where applicable. properties: properties[_cycle]: type: string description: >- JSON-encoded cycle blueprint to be submitted as a line item property properties[_validations]: type: string description: >- JSON-encoded validations to be submitted as a line item property selling_plan: type: integer nullable: true description: >- Shopify selling plan ID (present for Calendar, Subscription, and Membership options) additionalProperties: true add_ons: type: array description: >- Additional variants that must be added to the cart as separate line items (e.g. deposits, card authorisations) items: type: object properties: id: type: integer description: Shopify variant ID of the add-on cart_quantity: type: integer description: >- Maximum quantity of this add-on that should be present in the cart selling_plan: type: integer nullable: true description: Selling plan ID for the add-on, if applicable additionalProperties: true available_item_count: type: integer description: >- Number of available inventory items for the variant within the requested schedule required: - attributes - add_ons - available_item_count examples: calendar: summary: Calendar intent response value: attributes: properties[_cycle]: '{...}' properties[_validations]: '{...}' selling_plan: 1234 add_ons: [] available_item_count: 3 subscription: summary: Subscription intent response (with deposit add-on) value: attributes: properties[_cycle]: '{...}' properties[_validations]: '{...}' selling_plan: 1234 add_ons: - id: 4321 quantity: 1 selling_plan: 1234 cart_quantity: 1 available_item_count: 3 membership: summary: Membership intent response value: attributes: properties[_cycle]: '{...}' properties[_validations]: '{...}' properties[_credit_cost]: '5' selling_plan: 1234 add_ons: [] available_item_count: 3 '422': description: >- Unprocessable entity - variant not found, option not found, or method not enabled content: application/json: schema: type: object properties: error: type: string required: - error examples: variant_not_found: summary: Variant not found value: error: Cannot find variant with ID 123456789 option_not_found: summary: Option not found value: error: >- Cannot find option gid://supercycle/CalendarRental::RentalPeriod/1 method_not_enabled: summary: Method not enabled value: error: Method is not enabled '500': description: Server error ````