> ## Documentation Index > Fetch the complete documentation index at: https://docs.doofinder.com/llms.txt > Use this file to discover all available pages before exploring further. # Register an add-to-cart event > Registers that a product recommended by a specific widget was added to the cart ## OpenAPI ````yaml /openapi/recommendations-v1.yaml post /api/widget/{widget_id}/cart openapi: 3.0.0 info: title: Recommendations API contact: name: Doofinder Support url: https://docs.doofinder.com/ version: 1.0.0 description: > # Introduction Recommendations API allows you to retrieve personalized product recommendations for your ecommerce website using Doofinder's recommendation engine. # Basics ## Endpoint All requests should be done with `https` protocol in our api location. `https://{search_zone}-recommendations.doofinder.com` where `{search_zone}` depends on your location, is the geographic zone your recommendation engine is located at. i.e.: eu1. Also, indicates which host to use in your API calls. ## Conventions Along most of the code samples you will find placeholders for some common variable values. They are: - `{widget_id}`: The recommendation widget's unique UUID. i.e.: 123e4567-e89b-12d3-a456-426614174000 - `{session_id}`: Session identifier for tracking user behavior. i.e.: b2b89619844f4eb0b5fa19f28a19d679 - `{user_id}`: Unique user identifier. i.e.: 8c80694b-354c-4533-acd1-e4b8e7d74b7b - `{hashid}`: The hash identifier for the search engine. i.e.: de8f052ea612f95b6950d4013dd6ef38 ## Caveats ### Session IDs Some types of recommendations rely on user data to provide personalized product recommendations. If such data is not provided, the API will use fallback results, if fallback is enabled. If neither user data is provided nor fallback is enabled, then no recommendations will be returned. Currently, the **Browsing history** recommendation type is the only one that requires a `session_id` to be included in the request. ### CORS If CORS is enabled for your ecommerce site, it is important to ensure that the domain from which you make requests is correctly included in the request's `Origin` and/or `Referer` headers. This allows the domain to be validated against the list of allowed domains for your store. Otherwise, a **`403 Forbidden Origin`** will be returned, blocking the request for security reasons. ### Blocked IPs If the IP address from which the request originates is blacklisted in your store configuration, a **`403 Forbidden IP`** will be returned, blocking the request for security reasons. termsOfService: https://www.doofinder.com/es/terms-and-conditions x-logo: url: https://admin.doofinder.com/images/logo.svg backgroundColor: '#33268C' altText: Doofinder Recommendations Engine servers: - url: https://{search_zone}-recommendations.doofinder.com variables: search_zone: enum: - eu1 - us1 - ap1 default: eu1 security: [] tags: - name: Recommendations description: Recommendation operations for personalized product suggestions. paths: /api/widget/{widget_id}/cart: post: tags: - Recommendations summary: Register an add-to-cart event description: >- Registers that a product recommended by a specific widget was added to the cart operationId: registerWidgetAddToCart parameters: - name: widget_id in: path required: true description: Unique identifier for the widget schema: type: string format: uuid example: 123e4567-e89b-12d3-a456-426614174000 requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/AddToCartRequest' responses: '200': description: Add-to-cart event processed, check the status field for the outcome content: application/json: schema: type: object properties: status: type: string enum: - OK - ERROR example: OK '400': description: Bad Request - Missing required parameters or validation errors content: application/json: schema: $ref: '#/components/schemas/BadRequestError' '403': description: Forbidden - Access denied content: application/json: schema: type: object properties: error: type: string enum: - Forbidden origin - Forbidden ip example: error: Forbidden origin '404': description: Not Found - Resource not found content: application/json: schema: $ref: '#/components/schemas/NotFoundError' '429': description: Too Many Requests - Rate limit exceeded content: application/json: schema: type: object properties: error: type: string example: Too many request components: schemas: AddToCartRequest: type: object required: - session_id - dfid - title - price properties: session_id: type: string description: Session identifier for tracking user behavior example: b2b89619844f4eb0b5fa19f28a19d679 dfid: type: string description: Doofinder's unique ID for the item added to the cart example: >- 123e4567e89b12d3a456426614174000@product@e7b7a6c35b2d4afc94991bfc8100227a title: type: string description: The item title amount: type: integer description: Quantity added to the cart (optional, default 1) example: 1 price: type: number format: float description: The item price BadRequestError: type: object properties: error: type: string description: General error message example: Bad request details: type: object description: Field-specific validation errors additionalProperties: type: array items: type: string example: session_id: - length must be less than or equal to 32 user_id: - is required current_url: - is required required: - error NotFoundError: type: object properties: error: type: string description: Error message example: Not found resource: type: string description: Type of resource that was not found example: Widget resource_id: type: string description: ID of the resource that was not found example: cc1e4567-e89b-12d3-a456-426614174000 required: - error ````