> ## 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.
# List accounting periods
> Required API key scope: `accounting:read`
Returns accounting periods for the entity. Each period has a status of
open, close_requested, or closed. Closed periods refuse new JE postings.
## OpenAPI
````yaml /openapi.yaml get /periods
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:
/periods:
get:
tags:
- Accounting
summary: List accounting periods
description: |
Required API key scope: `accounting:read`
Returns accounting periods for the entity. Each period has a status of
open, close_requested, or closed. Closed periods refuse new JE postings.
operationId: listPeriodsV1
parameters:
- name: status
in: query
schema:
type: string
enum:
- open
- close_requested
- closed
- name: fiscal_year
in: query
schema:
type: integer
description: Filter by fiscal year (e.g. 2025)
responses:
'200':
description: List of accounting periods
content:
application/json:
schema:
type: object
properties:
data:
type: array
items:
$ref: '#/components/schemas/AccountingPeriod'
'401':
$ref: '#/components/responses/Error'
'403':
$ref: '#/components/responses/Error'
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
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.
````