> ## 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. # Create an order > Creates an order in one atomic transaction, optionally including line items, a header-level discount, tax calculation, inventory allocation, and an initial payment inline; any failure rolls back the whole request. The response returns a fully hydrated order with computed totals, and supports an `Idempotency-Key` header to safely retry without creating a duplicate. ## OpenAPI ````yaml /openapi.yaml post /orders 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. **Changelog.** Entries are dated and name every published contract whose MEANING moved, not only the ones whose field names changed. The narrative version of the same entries, written for integrators, is published at https://arcuserp.mintlify.app/changelog. **2026-09-22 (planned 2026-09-21), REORDER-BUYER-TRUTH: demand changed what it MEANS on three published contracts, with no field renamed.** An integrator that pins field names sees no breakage and different numbers, which is why this entry exists. - **Demand now counts build consumption.** `demand_avg_per_day` on the public product, kit and inventory-balance objects, and `daily_demand` / `demand_basis` / `net_suggested_qty` on `GET /v1/purchasing/reorder-report`, are composed from fulfilled sales lines PLUS posted `build_consume` inventory draws: each physical decrement of a product counts exactly once. The previous rule adopted an internal-consumption basis only when the sales blend was exactly zero, so a product both sold AND consumed into work orders planned as if the build draws did not exist. Products drawn into work orders move; on one production-shaped dataset five did, the largest from 0.05/day to 14.95/day. - **`demand_basis` now carries four values, not two:** `sales`, `sales_and_builds`, `builds` and `consumption`. A consumer with a two-branch reader (anything that is not `consumption` is `sales`) silently hides the two new ones. - **`current_demand_units` on `GET /v1/inventory/balances/:id` moved, by a second rule.** It counts committed-but-unshipped CUSTOMER demand, and it now counts a kit component's own line rather than its parent kit line, and excludes non-sales documents. On one production dataset 269 of 1,043 balance rows changed, 227 of them downward; the largest single move was 1,941 to 25, on a product whose open PURCHASE order line had been reported as customer demand. Re-baseline anything that alerts or reorders off this field. - `run_rate_30/90/180/365` and `blended_daily` on the same balance object move for the first reason above. - **Added, not changed:** `GET /v1/purchasing/reorder-report` accepts `demand_window` and returns the unit, cover-through and reorder-point-provenance fields documented on that operation; `order_multiple` is accepted and returned on the product-vendor doors. - **Volume note.** The `inventory.low_stock`, `inventory.out_of_stock` and `inventory.back_in_stock` webhook events are population-gated on `on_hand <= reorder_point`, and reorder points move with the demand above, so subscribers should expect a one-time step change in event volume around the release. 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: /orders: post: tags: - Orders summary: Create an order description: >- Creates an order in one atomic transaction, optionally including line items, a header-level discount, tax calculation, inventory allocation, and an initial payment inline; any failure rolls back the whole request. The response returns a fully hydrated order with computed totals, and supports an `Idempotency-Key` header to safely retry without creating a duplicate. operationId: createOrder parameters: - $ref: '#/components/parameters/IdempotencyKey' requestBody: required: true content: application/json: schema: type: object required: - document_type - account_id properties: document_type: type: string enum: - quote - sales_order - invoice - return - purchase_order description: >- Discriminator. sales_order and invoice are for customer accounts; purchase_order for vendors. account_id: type: string format: uuid description: >- Customer or vendor account. Account defaults (pricing level, addresses, payment terms) are auto-inherited. location_id: type: string format: uuid description: >- Warehouse location for inventory allocation. Defaults to entity default location. shipping_address_id: type: string format: uuid description: >- Shipping address. Auto-resolved from account default when omitted. billing_address_id: type: string format: uuid description: >- Billing address. Auto-resolved from account default when omitted. payment_term_id: type: string format: uuid description: >- Payment terms (e.g. Net 30). Auto-resolved from account, channel, and entity default cascade. sales_channel_id: type: string format: uuid pricing_level_id: type: string format: uuid description: >- Override pricing level. Auto-resolved from account default when omitted. po_number: type: string description: Customer purchase order number. order_date: type: string format: date-time description: Order date. Defaults to now. notes: type: string description: Customer-visible notes. internal_notes: type: string description: Internal-only notes. customer_notes: type: string requested_ship_date: type: string format: date ship_complete: type: boolean description: >- When true, do not ship partial. Inherited from account default. default_shipping_method: type: string nullable: true description: >- Order-header shipping-method override. Accepts a Shippo service token (e.g. 'ups_ground') or a carrier service name (e.g. 'UPS Ground'); stored canonicalized as the token. Unrecognized values return 400 validation_failed. Omitted: inherited from the account's Default Ship Method when set. Drives rate-shop suggested-service selection (header override beats shipping rules). ships_freight: type: boolean tax_exempt: type: boolean description: >- Mark order tax-exempt. Requires avatax_entity_code on the order or linked account. avatax_entity_code: type: string description: AvaTax exemption entity code (e.g. 'RESALE', 'EXEMPT'). sales_agent_id: type: string format: uuid metadata: type: object description: Arbitrary key-value metadata stored on the order. line_items: type: array description: >- Inline line items. Inserted atomically with the order. Any failure rolls back all items and the order header. items: type: object required: - product_id - quantity properties: product_id: type: string format: uuid variant_id: type: string format: uuid description: Required when the product has variants. quantity: type: number description: Quantity. Must be > 0. sell_rate: type: number description: >- Override unit price (canonical Arcus field). Omit to use pricing engine (qty-break + level defaults). unit_price: type: number description: >- Alias for sell_rate (Stripe/Shopify convention). Either name accepted; supplying both with different values returns 400 price_field_conflict. Negative or zero returns 422 invalid_price. When applied price differs from catalog list_price, response carries warnings array entries (code price_override, catalog_price, applied_price, delta) plus one order.price_override audit_log row per overridden line. NEW-GAP-API-V1-CALLER-UNIT-PRICE-SILENTLY-OVERRIDDEN closure 2026-05-17. notes: type: string discount: type: object description: Header-level discount applied to the order subtotal. properties: type: type: string enum: - percentage - flat value: type: number description: Percentage (0-100) or flat dollar amount. auto_compute_tax: type: boolean description: >- Run AvaTax (or local rate) after all items are inserted. Requires shipping_address_id to resolve to a taxable jurisdiction. auto_allocate_inventory: type: boolean description: >- Reserve inventory per line item. Returns 422 with shortfall details if any line has insufficient stock. Rollback is atomic. payments: type: array description: >- Inline payment(s). Fired after the order is committed. Payment failure does NOT roll back the order. items: type: object required: - payment_method_id - amount properties: payment_method_id: type: string format: uuid description: Arcus internal UUID from account_payment_methods. amount: type: number description: Amount to charge in USD. payment_type: type: string enum: - card - ach - cash - check - credit - terms - external default: card auto_capture: type: boolean default: true save_card: type: boolean description: Attach card to account for future off-session use. example: document_type: sales_order account_id: c3f2a7b1-0e44-4f89-9d12-aabb0c123456 location_id: a1b2c3d4-e5f6-7890-abcd-ef1234567890 shipping_address_id: d4e5f6a7-b8c9-0123-def4-567890abcdef billing_address_id: e5f6a7b8-c9d0-1234-ef56-7890abcdef01 shipping_method: ups_ground line_items: - product_id: 11111111-2222-3333-4444-555555555555 quantity: 5 - product_id: 22222222-3333-4444-5555-666666666666 quantity: 3 - product_id: 33333333-4444-5555-6666-777777777777 variant_id: 44444444-5555-6666-7777-888888888888 quantity: 10 discount: type: percentage value: 5 auto_compute_tax: true auto_allocate_inventory: true payments: - payment_method_id: 55555555-6666-7777-8888-999999999999 amount: 750 payment_type: card auto_capture: true responses: '201': description: Created order (hydrated with line_items, payments, tax_lines) content: application/json: schema: $ref: '#/components/schemas/Order' '400': $ref: '#/components/responses/Error' '401': $ref: '#/components/responses/Error' '403': $ref: '#/components/responses/Error' '404': description: > `account_not_found`: the `account_id` names no account of the key's entity. `address_not_found`: a `shipping_address_id` or `billing_address_id` names no address of an account of the key's entity. An id of another entity and an id that does not exist give the same answer, and nothing is created. content: application/json: schema: $ref: '#/components/schemas/Error' '409': $ref: '#/components/responses/Error' '422': $ref: '#/components/responses/Error' security: - ApiKeyAuth: [] components: parameters: IdempotencyKey: name: Idempotency-Key in: header required: false description: | Client-generated unique key for idempotent POST/PATCH/DELETE operations. Alias for the Idempotency parameter. Max 255 chars. On retry with the same key, the original response is returned without re-executing the operation. Keys expire after 24 hours. schema: type: string maxLength: 255 schemas: Order: type: object description: > An Arcus ERP order document. One table holds quotes, sales_orders, invoices, returns, and purchase_orders -- always filter by document_type. entity_id is always from the API key (Layer 1 isolation). properties: id: type: string format: uuid object: type: string enum: - order entity_id: type: string format: uuid readOnly: true order_number: type: string readOnly: true document_type: type: string enum: - quote - sales_order - invoice - return - purchase_order order_status: type: string enum: - draft - confirmed - partially_fulfilled - fulfilled - cancelled - voided - awaiting_ach_clearance - on_hold payment_status: type: string enum: - unpaid - partially_paid - paid - overpaid - refunded - partially_refunded - voided fulfillment_status: type: string enum: - unfulfilled - partially_fulfilled - fulfilled account_id: type: string format: uuid nullable: true location_id: type: string format: uuid nullable: true po_number: type: string nullable: true order_date: type: string format: date-time nullable: true due_date: type: string format: date-time nullable: true subtotal: type: number discount_total: type: number shipping_total: type: number tax_total: type: number fee_total: type: number order_total: type: number list_price_total: type: number readOnly: true description: >- Derived (display-only): SUM(list_price * qty) over non-kit lines. The gross baseline of the gross-to-net bridge (List price minus pricing_savings equals subtotal). Never part of order_total. pricing_savings: type: number readOnly: true description: >- Derived (display-only): SUM(pricing_rule_adjustment * qty) over non-kit lines (positive magnitude). Per-unit pricing-rule savings already baked into subtotal via sell_rate (ASC 606 transaction price); shown as an informational List-to-Subtotal bridge, never subtracted from order_total. amount_paid: type: number readOnly: true description: 'SSOT: utils/ar-helpers.mjs::updateARBalance. Do not write directly.' balance_due: type: number readOnly: true description: >- AR receivable (the amount this document is owed AS A RECEIVABLE). Forced to 0 on DRAFT sales documents, on cancelled / archived / expired orders, and on voided or fully-refunded invoices, because none of those carries a receivable: a draft is not a receivable, and a terminal document owes nothing. This is the number that ties to AR aging, the AR outstanding total, and the GL AR control account. For the amount still COLLECTIBLE on any document at any status (including a draft), use `amount_due`. Purchase orders and quotes are never forced to 0. SSOT: utils/ar-helpers.mjs::updateARBalance. Do not write directly. amount_due: type: number readOnly: true description: >- Collectible remainder: order_total minus amount_paid, rounded to 2 decimals. Status-blind BY DESIGN, so it answers "how much is still OUTSTANDING on this document as simple arithmetic" even where `balance_due` is 0 because the document is not (yet) a receivable. Negative when the customer has overpaid (money owed back to them). On a confirmed, non-refunded document with no sales allowance and no cancellation, `amount_due` and `balance_due` are equal. NOT A PAYABLE AMOUNT. Because it is status-blind it stays positive on documents that can accept no payment at all -- a cancelled / archived / expired order, a voided invoice, a fully-refunded order -- and it OVERSTATES what is owed on an allowance-settled order (a standalone concession refund reversed goods or tax: `balance_due` correctly settles to 0 while the remainder does not). Collecting `amount_due` on either shape creates an overpayment, and the payment endpoints will refuse it with `order_not_payable` (422). To decide how much to collect, take the amount from the payment surface you are about to call (`POST /v1/orders/{id}/payments` validates and caps server-side); to reconcile against AR aging or the GL AR control account, use `balance_due`. tax_exempt: type: boolean delivery_option: type: string enum: - ship - pick_up - local_delivery notes: type: string nullable: true internal_notes: type: string nullable: true invoice_number: type: string nullable: true readOnly: true invoice_type: type: string enum: - order - manual - proforma - correction nullable: true is_on_hold: type: boolean readOnly: true hold_type: type: string nullable: true readOnly: true ship_complete: type: boolean source_platform: type: string nullable: true external_order_id: type: string nullable: true external_order_number: type: string nullable: true metadata: type: object nullable: true created_at: type: string format: date-time readOnly: true updated_at: type: string format: date-time readOnly: true Error: description: | Alias for ErrorEnvelope. Canonical error response shape used by all API endpoints. Refer to ErrorEnvelope for the full field definition. allOf: - $ref: '#/components/schemas/ErrorEnvelope' 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. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.