> ## 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.
# Assess late fees (finance charges)
> Required API key scope: `accounting:write`
Triggers finance charge assessment for the entity. By default assesses all overdue
invoices for all active customer accounts. Pass `account_id` to scope to a single
customer. Pass `dry_run: true` to preview which invoices would receive a charge and
the calculated amounts without persisting any records.
**Assessment logic:** For each overdue invoice the handler checks eligibility
(account not late-fee-exempt, invoice status open/partially_paid, balance_due
meets the entity minimum, grace period elapsed, no same-day duplicate). The fee
is calculated per the entity compounding mode (`monthly`, `daily`, or `none`).
A new `late_fee_invoice` document is created and a GL journal entry is posted
(DR accounts_receivable 1300 / CR finance_charge_income 4220) per ASC 310-10-35.
**Entity settings required:** `late_fee_enabled` must be `true` and
`late_fee_rate_percent` must be a non-null positive number in the entity settings
before any charges are assessed.
**Idempotency:** At most one late-fee invoice is issued per source invoice per day.
Repeated calls on the same day return `skipped` results for already-charged invoices.
## OpenAPI
````yaml /openapi.yaml post /ar/assess-late-fees
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:
/ar/assess-late-fees:
post:
tags:
- Accounting
summary: Assess late fees (finance charges)
description: >
Required API key scope: `accounting:write`
Triggers finance charge assessment for the entity. By default assesses
all overdue
invoices for all active customer accounts. Pass `account_id` to scope to
a single
customer. Pass `dry_run: true` to preview which invoices would receive a
charge and
the calculated amounts without persisting any records.
**Assessment logic:** For each overdue invoice the handler checks
eligibility
(account not late-fee-exempt, invoice status open/partially_paid,
balance_due
meets the entity minimum, grace period elapsed, no same-day duplicate).
The fee
is calculated per the entity compounding mode (`monthly`, `daily`, or
`none`).
A new `late_fee_invoice` document is created and a GL journal entry is
posted
(DR accounts_receivable 1300 / CR finance_charge_income 4220) per ASC
310-10-35.
**Entity settings required:** `late_fee_enabled` must be `true` and
`late_fee_rate_percent` must be a non-null positive number in the entity
settings
before any charges are assessed.
**Idempotency:** At most one late-fee invoice is issued per source
invoice per day.
Repeated calls on the same day return `skipped` results for
already-charged invoices.
operationId: assessLateFeesV1
requestBody:
content:
application/json:
schema:
type: object
properties:
account_id:
type: string
format: uuid
nullable: true
description: >-
Scope assessment to a single customer account. Omit to
assess all eligible accounts.
dry_run:
type: boolean
default: false
description: >-
Preview mode: calculates fees and returns preview data
without persisting any records or posting GL entries.
responses:
'200':
description: Late fee assessment results
content:
application/json:
schema:
type: object
properties:
assessed:
type: array
description: Invoices that received a finance charge
items:
type: object
properties:
source_order_id:
type: string
format: uuid
late_fee_order_id:
type: string
format: uuid
nullable: true
description: null when dry_run=true
account_id:
type: string
format: uuid
customer_name:
type: string
invoice_number:
type: string
balance_due:
type: number
fee_amount:
type: number
days_overdue:
type: integer
compounding:
type: string
enum:
- monthly
- daily
- none
skipped:
type: array
description: >-
Invoices that were evaluated but skipped (exempt, already
charged today, min not met, etc.)
items:
type: object
properties:
source_order_id:
type: string
format: uuid
account_id:
type: string
format: uuid
reason:
type: string
total_fee_amount:
type: number
description: Sum of all fee_amount values in the assessed array
dry_run:
type: boolean
description: >-
Reflects the dry_run parameter; true means no records were
persisted
'401':
$ref: '#/components/responses/Error'
'403':
$ref: '#/components/responses/Error'
'422':
description: >-
Late fees not configured for this entity (late_fee_enabled=false or
rate not set)
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
security:
- ApiKeyAuth: []
components:
responses:
Error:
description: Error response (400/401/403/404/409/422/429/500)
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorEnvelope'
schemas:
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
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.
````