> ## 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. # Close an accounting period > Closes an accounting period once it passes the close checklist, after which no journal entry can post with an entry date inside it; a year-end close with its retained-earnings rollover is a separate operation. Requires `accounting:close_period` scope, and closing a period that ended more than 180 days ago requires `acknowledge_old_period: true`. ## OpenAPI ````yaml /openapi.yaml post /periods/{id}/close 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: /periods/{id}/close: post: tags: - Accounting summary: Close an accounting period description: >- Closes an accounting period once it passes the close checklist, after which no journal entry can post with an entry date inside it; a year-end close with its retained-earnings rollover is a separate operation. Requires `accounting:close_period` scope, and closing a period that ended more than 180 days ago requires `acknowledge_old_period: true`. operationId: closePeriodV1 parameters: - name: id in: path required: true schema: type: string format: uuid requestBody: content: application/json: schema: type: object properties: notes: type: string acknowledge_old_period: type: boolean default: false description: >- Required true when the period ended more than 180 days ago. Closing an old period seals a range the books may already have been reported from, and reopening it later needs the same confirmation, so the close asks for it first. This is an acknowledgement, not a permission: closing an old period is legitimate and routine on books that are behind. Omit it on a period within 180 days and nothing changes. responses: '200': description: Closed period content: application/json: schema: $ref: '#/components/schemas/AccountingPeriod' '401': $ref: '#/components/responses/Error' '403': $ref: '#/components/responses/Error' '404': $ref: '#/components/responses/Error' '422': description: >- Period cannot be closed (has blocking issues), or the period is older than 180 days and `acknowledge_old_period` was not sent. The latter is code `period_too_old_for_simple_close` and carries `period_age_days` and `max_age_days_without_ack` so a client can put the period's own age in its sentence; re-submit with `acknowledge_old_period: true`. content: application/json: schema: allOf: - $ref: '#/components/schemas/Error' - type: object properties: period_age_days: type: integer description: >- How many days ago the period ended. Present only on `period_too_old_for_simple_close`. max_age_days_without_ack: type: integer description: >- The age beyond which the acknowledgement is required (180). Present only on `period_too_old_for_simple_close`. security: - ApiKeyAuth: [] components: schemas: AccountingPeriod: type: object description: > An accounting period. Closed periods refuse new journal entry postings (Rule A3). Year-end closing entries that roll revenue and expense activity into retained earnings are posted via a separate explicit endpoint (POST /v1/accounting_periods/{id}/close-fiscal-year). The monthly-period close does NOT by itself post a retained-earnings rollover JE. Verified against live dev RDS accounting.accounting_periods. properties: id: type: string format: uuid readOnly: true entity_id: type: string format: uuid readOnly: true period_name: type: string description: Human-readable name (e.g. 'January 2025') start_date: type: string format: date end_date: type: string format: date status: type: string enum: - open - close_requested - closed readOnly: true closed_by: type: string format: uuid nullable: true readOnly: true closed_at: type: string format: date-time nullable: true readOnly: true close_requested_by: type: string format: uuid nullable: true readOnly: true close_requested_at: type: string format: date-time nullable: true readOnly: true close_approved_by: type: string format: uuid nullable: true readOnly: true close_approved_at: type: string format: date-time nullable: true readOnly: true reopen_reason: type: string nullable: true readOnly: true description: >- NEW-GAP-REOPEN-PERIOD-ENTITY-ISOLATION-SOD-REASON-AUDIT (2026-05-15): operator-supplied justification from the most recent reopen. 10-500 chars when set. Cleared on next close. reopened_by: type: string format: uuid nullable: true readOnly: true description: User who most recently reopened this period. reopened_at: type: string format: date-time nullable: true readOnly: true created_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.