> ## Documentation Index > Fetch the complete documentation index at: https://docs.way.co/llms.txt > Use this file to discover all available pages before exploring further. # Get listing add-on availability > Returns the remaining inventory for each available add-on in one exact listing session. Use this endpoint when an add-on's `limitType` is `PER_SESSION`; availability is scoped by add-on, start date-time, and session duration. With an organization key, add a `Way-Brand-Id` header to check the listing against one of your brands. ## OpenAPI ````yaml get /v3/listings/{listingId}/add-ons/availability openapi: 3.0.0 info: title: Way Partner API description: >- REST API for Way partners: list experiences, check availability, run checkout, and manage bookings. version: '1.0' servers: - url: https://api.letsway.com description: Production. - url: https://api.staging.letsway.com description: Staging. security: [] tags: - name: Listings description: 'Retrieve the listings a brand offers: experiences, events, and resources.' - name: Availability description: Dates, sessions, and price tiers for scheduling a booking. - name: Carts & Checkout description: >- Payment intents and booking creation. The cart ID is a client-generated UUID; there is no create-cart endpoint. - name: Bookings description: Retrieve, cancel, and reschedule bookings. - name: Experiences description: Experience details, settings, custom questions, reviews, and hosts. - name: Brand Configuration description: Brand settings, taxonomy, terms, and promotion code validation. - name: Waitlists description: Waitlists for sold-out sessions and invitation handling. - name: Integrations description: Configured integrations, analytics, and room-charge validation. - name: Organizations description: Organization-level access across brands. paths: /v3/listings/{listingId}/add-ons/availability: get: tags: - Listings summary: Get listing add-on availability description: >- Returns the remaining inventory for each available add-on in one exact listing session. Use this endpoint when an add-on's `limitType` is `PER_SESSION`; availability is scoped by add-on, start date-time, and session duration. With an organization key, add a `Way-Brand-Id` header to check the listing against one of your brands. operationId: ListingV3PublicController_getAddOnAvailability parameters: - $ref: '#/components/parameters/listingIdPath_6' - $ref: '#/components/parameters/WayBrandIdHeader_7' - $ref: '#/components/parameters/experienceIdQuery' - $ref: '#/components/parameters/sessionDurationQuery' - $ref: '#/components/parameters/startDateTimeQuery' responses: '200': description: '' content: application/json: schema: $ref: '#/components/schemas/GetListingAddOnAvailabilityPublicResponse' example: items: - listingAddOnId: 1df45513-6f59-4b12-b9ea-66605de087f4 available: true availableQuantity: 3 - listingAddOnId: 61d47649-b547-4694-b6a5-b5675048189d available: true availableQuantity: null security: - Brand-API-Key: [] - Organization-API-Key: [] components: parameters: listingIdPath_6: name: listingId in: path schema: type: string required: true description: The listing's ID. example: 1f4877f4-a082-4a05-9cbf-fa129b28f01c WayBrandIdHeader_7: name: Way-Brand-Id in: header required: false description: >- The brand to check the listing against. Optional with an organization key. Ignored with a brand key, which already names its brand. schema: type: string format: uuid experienceIdQuery: name: experienceId in: query schema: type: string format: uuid description: The experience within the listing whose add-ons are being checked. example: c99f70ee-1c0e-4534-a31a-96d5d966cc4b required: false sessionDurationQuery: name: sessionDuration in: query schema: minimum: 0 exclusiveMinimum: true type: number description: Duration of the selected session in minutes. example: 90 required: false startDateTimeQuery: name: startDateTime in: query schema: type: string description: >- Start of the selected session as a local date-time in the experience's timezone, with no UTC offset. example: '2026-08-15T17:00:00' required: false schemas: GetListingAddOnAvailabilityPublicResponse: type: object properties: items: type: array items: type: object properties: listingAddOnId: type: string format: uuid description: The listing add-on ID returned by Get a listing. example: 1df45513-6f59-4b12-b9ea-66605de087f4 available: type: boolean description: >- Whether at least one unit remains available for the requested session. example: true availableQuantity: type: number minimum: 0 nullable: true description: >- Number of units remaining for a PER_SESSION add-on. Null when the add-on has no per-session limit. example: 3 required: - listingAddOnId - available - availableQuantity description: Availability for every add-on currently available on the listing. required: - items securitySchemes: Brand-API-Key: type: http scheme: bearer description: >- Your brand's secret API key, e.g. `Bearer way_sk_live_bhEqcn0i1fRoUEHBPjJkQA`. The key names the brand, so a `brandId` in the path must be your own brand. Older `Way-Brand-Id` + `Way-Secret-Key` credentials still work: see [Legacy authentication](/legacy-authentication). Organization-API-Key: type: http scheme: bearer description: >- Your organization's secret API key, e.g. `Bearer way_sk_live_ohEqcn0i1fRoUEHBPjJkQA`. The key authorizes every brand in the organization but does not by itself name one: see the endpoint description for how this request is scoped. Using `Way-Organization-Id` + `Way-Secret-Key` credentials? See [Legacy authentication](/legacy-authentication). ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.