> ## Documentation Index > Fetch the complete documentation index at: https://docs.joinluminous.com/llms.txt > Use this file to discover all available pages before exploring further. # Get cost layer by ID > Retrieve a single legacy FIFO/WAC cost layer (`rfq_stock_cost_layers`) by ID. Returns the same object shape as the list endpoint. Returns `404` when the layer does not exist or has been soft-deleted. ## OpenAPI ````yaml /api-reference/build.yaml get /inventory/cost-layers/{costLayerId} openapi: 3.0.0 info: title: Luminous API version: 1.0.0 description: API documentation for Luminous servers: - url: https://{companyName}.api.joinluminous.com/external/api/v1 variables: companyName: default: companyName description: Your company-specific subdomain security: [] tags: - name: Products description: Get and manage products - name: Pricing description: Manage price schedules, levels, and customizations - name: BOMs description: Manage Bills of Materials (BOMs) - name: Labels description: Label rendering via Labelary ZPL service - name: Companies description: Manage business accounts and their associated data - name: Contacts description: Manage contact information for individuals - name: Suppliers description: Manage suppliers (factories) — vendors used on purchase orders - name: Supplier SKUs description: Manage per-supplier SKU and unit-cost overrides for products - name: Locations description: Manage warehouses and locations - name: Inventory description: Get and adjust product stock levels - name: Lots description: Create, update, and delete product lots (batches) - name: Transfer Orders description: Manage transfer orders - name: Fulfillment Orders description: Manage fulfillment orders and picklists - name: Fulfillment Priority Lists description: Configure fulfillment routing priority lists - name: Purchase Orders description: Get and modify purchase orders - name: Supplier Portal description: >- Read a supplier's response to a purchase order and control the one-click portal link - name: Receiving Reports description: Manage receiving reports - name: Payment Obligations description: Manage payment obligations for purchase orders - name: Sales Orders description: Manage sales orders and sales order shipments - name: Purgatory description: >- Inspect and resolve non-posted sales orders in the purgatory staging workflow - name: PickFlow Shipping description: >- Provider-agnostic shipping rates, services, packages, and label purchase for PickFlow - name: Cycle Counts description: >- Create, drive, and post PickFlow cycle counts — batches, per-warehouse sessions, and CSV import/export - name: Print Stations description: List paired print stations and enqueue print jobs to them - name: Invoices description: Get and manage invoices - name: Work Orders description: >- Manage work orders — production lifecycle, steps, materials, links, shipments, and comments - name: Production Batches description: Group and manage work orders as production batches - name: Bills description: >- Accounts payable bill management, payments, attachments, allocations, and variance - name: Prepayments description: Manage vendor prepayments and applications - name: Vendor Credits description: Manage vendor credits and applications - name: Vendor Returns description: Manage vendor returns and credit generation - name: Customer Returns description: Manage customer returns (sales returns), receiving, and restock behavior - name: Stock Snapshot description: Point-in-time stock snapshots with export support - name: Consumption description: Consumption reports and exports - name: Inventory Aging description: Cost-layer-based inventory aging reports - name: Bills Reports description: Accounts payable bills aging reports - name: Forecast description: Materialized forecast data - name: Reports description: Close the books, inventory discrepancy, transaction COGS, and EDI reports - name: Tags description: Add/remove tags across various resources - name: Custom Fields description: Get and set custom fields across various resources - name: Currency description: Currency configuration, exchange rates, and conversion - name: Integration Mappings description: Manage integration mappings for external systems - name: Integration Field Mappings description: Manage field-level mappings between Luminous and external systems paths: /inventory/cost-layers/{costLayerId}: get: tags: - Inventory summary: Get cost layer by ID description: > Retrieve a single legacy FIFO/WAC cost layer (`rfq_stock_cost_layers`) by ID. Returns the same object shape as the list endpoint. Returns `404` when the layer does not exist or has been soft-deleted. operationId: getCostLayer parameters: - in: path name: costLayerId required: true schema: type: integer description: The cost layer ID. responses: '200': description: The requested cost layer. content: application/json: schema: type: object properties: data: type: object description: > A legacy FIFO/WAC cost layer (`rfq_stock_cost_layers`). Each layer represents a quantity of a product received into a warehouse at a specific unit cost. These are distinct from Luminous Core inventory-cost ledger rows (see `/core/inventory-costs`). properties: layer_id: type: integer description: Cost layer ID. received_at: type: string nullable: true description: >- When the layer was received (`YYYY-MM-DD HH:mm:ss`). Derived from the layer creation date. example: '2024-06-01 14:22:00' original_quantity: type: number format: float description: Original quantity received into the layer. remaining_quantity: type: number format: float description: >- Quantity still remaining on the layer. `0` for fully depleted layers. unit_cost: type: number format: float description: Cost per unit for the layer. extended_value: type: number format: float description: >- Remaining value of the layer (`remaining_quantity` × `unit_cost`). product_id: type: integer description: Product (RFQ) ID the layer belongs to. sku: type: string nullable: true description: >- Product internal SKU. Only present when the product relation is loaded. warehouse_id: type: integer nullable: true description: Warehouse / location ID the layer is held at. is_variance: type: boolean description: >- Whether the layer was created from an inventory variance/adjustment. '401': description: Unauthorized content: application/json: schema: type: object properties: message: type: string '404': description: Cost layer not found. content: application/json: schema: type: object properties: message: type: string security: - BearerAuth: [] components: securitySchemes: BearerAuth: type: http scheme: bearer description: >- Authenticate using a bearer token. To create a token, navigate to /settings/api-tokens and click Create API Token. ````