> ## Documentation Index > Fetch the complete documentation index at: https://docs.arcuserp.com/llms.txt > Use this file to discover all available pages before exploring further. # Retrieve a product > Returns the full detail of a single product by UUID or SKU, including pricing tiers, vendor mappings, unit-of-measure settings, tax category, and custom-field values. Use `?expand[]=variants`, `?expand[]=vendors`, or `?expand[]=listings` to hydrate nested collections inline. Requires `products:read` scope. Polymorphic path parameter: pass a UUID or a SKU (e.g. WDG-PRO-XL, RISER-DOME). If a non-UUID slug is provided it is resolved to the matching product UUID within the entity scope. Returns 404 if no product matches either form. (NEW-GAP-API-V1-POLYMORPHIC-LOOKUP-CROSS-RESOURCE 2026-05-20) ## OpenAPI ````yaml /openapi.yaml get /products/{id} openapi: 3.1.0 info: title: Arcus ERP Public API version: 1.0.0 description: > Arcus ERP public REST API. Designed for external integrations and data migration. **Authentication.** Bearer token (API key) via the `Authorization` header. Format: `Authorization: Bearer ark_live_ent__` (or `ark_test_*` for sandbox). API keys are issued per-entity in **Settings > Developers > API Keys**. **Entity scoping.** The entity is encoded in the API key prefix; routes are flat (e.g. `/v1/accounts`, `/v1/orders`, `/v1/products`). A small set of platform endpoints (migration, reconciliation, events, webhook endpoints, API keys) use the `/v1/entities/{entity_id}/...` form -- those are noted in their tags. **Key capabilities.** - Related-resource hydration via `?expand[]=` (see `x-arcus-expand` on each resource). - Cursor-based pagination (`starting_after` / `ending_before` / `limit`). - Idempotency via the `Idempotency-Key` header. - Webhook events for asynchronous notification. - Conditional requests / ETag for cache validation. servers: - url: https://api.arcuserp.com/v1 description: Arcus ERP API (accepts both live `ark_live_*` and test `ark_test_*` keys) - url: https://dev-api.arcuserp.com/v1 description: >- Dev sandbox API (test-only data, accepts `ark_test_*` keys against dev RDS) security: [] paths: /products/{id}: get: tags: - Products summary: Retrieve a product description: > Returns the full detail of a single product by UUID or SKU, including pricing tiers, vendor mappings, unit-of-measure settings, tax category, and custom-field values. Use `?expand[]=variants`, `?expand[]=vendors`, or `?expand[]=listings` to hydrate nested collections inline. Requires `products:read` scope. Polymorphic path parameter: pass a UUID or a SKU (e.g. WDG-PRO-XL, RISER-DOME). If a non-UUID slug is provided it is resolved to the matching product UUID within the entity scope. Returns 404 if no product matches either form. (NEW-GAP-API-V1-POLYMORPHIC-LOOKUP-CROSS-RESOURCE 2026-05-20) operationId: getProduct parameters: - name: id in: path required: true schema: type: string description: >- Product UUID or SKU (e.g. WDG-PRO-XL). Polymorphic lookup resolves SKU to UUID within entity scope. - $ref: '#/components/parameters/Expand' - $ref: '#/components/parameters/Fields' responses: '200': description: Product object content: application/json: schema: type: object properties: data: $ref: '#/components/schemas/Product' '401': $ref: '#/components/responses/Error' '403': $ref: '#/components/responses/Error' '404': $ref: '#/components/responses/Error' security: - ApiKeyAuth: - products:read components: parameters: Expand: name: expand in: query description: > Related-resource hydration. Provide one or more paths to expand; nested via dot syntax (e.g. expand[]=line_items.product). Rules: - Max depth: 4 - Max paths per request: 10 - List endpoints REQUIRE the "data." prefix on every path (e.g. GET /v1/orders uses expand[]=data.customer, not expand[]=customer) - Per-relation hydrated count cap: 100 rows. Exceeding rows return reference IDs only with truncated: true. - Per-path scope assertion: each path requires the corresponding :read scope on the API key. e.g. expanding "customer" on an order requires accounts:read. Valid expand paths per resource are documented in x-arcus-expand extensions on individual endpoint operations. required: false style: form explode: true schema: type: array maxItems: 10 items: type: string maxLength: 100 pattern: ^[a-zA-Z_][a-zA-Z0-9_.]{0,99}$ examples: single: summary: Single related resource value: - customer nested: summary: Nested related resource value: - line_items.product listPrefix: summary: List endpoint (requires data. prefix) value: - data.customer - data.line_items.product Fields: name: fields in: query required: false description: | Sparse fieldset selector. Comma-separated list of top-level fields to include in the response. When omitted, the full default response is returned. The id field is always included. Example: fields=id,name,email schema: type: string maxLength: 1000 schemas: Product: type: object description: Arcus ERP product (physical/kit/box/service/variant_parent). properties: id: type: string format: uuid object: type: string enum: - product entity_id: type: string format: uuid readOnly: true title: type: string description: type: string nullable: true sku: type: string nullable: true part_number: type: string nullable: true barcode: type: string nullable: true product_type: type: string enum: - physical - kit - box - service - variant_parent category_id: type: string format: uuid nullable: true vendor_id: type: string format: uuid nullable: true list_price: type: number cost: type: number readOnly: true description: >- WAC (Weighted Average Cost). ReadOnly. Writers: updateProductCostFromReceipt + recomputeKitCostForKit. is_active: type: boolean is_serialized: type: boolean charge_tax: type: boolean track_inventory: type: boolean weight: type: number nullable: true weight_uom: type: string length: type: number nullable: true width: type: number nullable: true height: type: number nullable: true length_uom: type: string quantity_uom: type: string product_tax_code: type: string nullable: true reorder_point: type: integer nullable: true reorder_qty: type: integer nullable: true safety_stock: type: integer packaging_classification: type: string enum: - over_box - sioc - sipp - prep_free default: over_box description: > Amazon-FBA packaging classification driving PackPilot's pack-order decisions. `over_box` (default): standard path, PackPilot picks an over-box from the catalog and the warehouse runs the full prep step. `sioc` (Ships In Own Container): item ships in its original manufacturer container; the shipping label tapes directly onto the product packaging; no over-box and no prep. Single-item package only (cannot co-pack). `sipp` (Ships In Product Packaging): Amazon's rebrand of SIOC with identical rules: retail packaging IS ship-ready and the label goes onto it. Single-item package only. `prep_free` (Prep-Free Packaging): item still requires an over-box (PackPilot picks one) but the warehouse skips the prep step (no bubble wrap, no bagging, no labels-on-product). Can co-pack with other prep-free or over_box items. Added 2026-05-18 in Phase 3 of FULFILLMENT-PRODUCTION-READINESS-CAMPAIGN; backed by the `packaging_classification` Postgres ENUM. has_variants: type: boolean readOnly: true metadata: type: object description: >- Operator-extensible JSONB. Reserved: _deleted (set by softDeleteProduct), _actor, _api. created_at: type: string format: date-time readOnly: true updated_at: type: string format: date-time readOnly: true ErrorEnvelope: type: object description: | Canonical error response envelope. All API errors use this shape. required: - error - code properties: error: type: string description: Machine-readable error key example: not_found code: type: string description: Machine-readable error code (often same as error) example: not_found type: type: string enum: - validation_error - permission_error - not_found - conflict - rate_limit - internal - expand_error - not_implemented example: not_found hint: type: string description: Human-readable one-sentence explanation (English) example: >- The requested order does not exist or does not belong to this entity. param: type: string description: The parameter that caused the error, if applicable example: expand[0] required: type: string description: The scope required (only on insufficient_scope errors) example: accounts:read request_id: type: string description: >- Unique request ID for support tracing (maps to CloudWatch log stream) example: req_abc123 responses: Error: description: Error response (400/401/403/404/409/422/429/500) content: application/json: schema: $ref: '#/components/schemas/ErrorEnvelope' securitySchemes: ApiKeyAuth: type: http scheme: bearer description: | API key issued per entity via Settings > Developers > API Keys. Each key carries scopes (e.g. orders:read, products:write). Bearer token format: Authorization: Bearer ark_live_ent__ Test keys use ark_test_ent__. Both are issued per entity via Settings > Developers > API Keys. ````