> ## 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. # Void an AP payment with GL reversal > **Authorization:** requires `purchasing:write` API-key scope AND the per-user `payments.refund_void` permission (SoD parity sweep 2026-05-16; AICPA SoD 4-role split treats AP void as highest-trust action -- manager DENIED by default). System-actor calls denied. Voids an AP payment, reversing the disbursement GL journal entry (today-dated reversal in the current open period -- closed periods are never mutated), voiding the linked check (including reversal of the check-cleared entry when the check had cleared), restoring any vendor-credit consumption to the cent, and re-opening EVERY bill the payment covered via the canonical AP balance writer. A multi-bill check payment re-opens ALL of its bills; call `GET /ap/payments/:id/void-preview` (internal UI endpoint) or inspect `void_summary` in the response to enumerate the effect. The void is reflected in the vendor's AP aging immediately. **`reason` is REQUIRED** (audited; 422 `void_reason_required` when absent). Typed rejections: 409 `payment_already_voided` (double-void), 409 `historical_row_immutable` (migrated rows), 422 `ach_payment_not_voidable` (ACH in flight or settled -- cancel at the bank / record a vendor credit instead), 422 `payment_reconciled_blocks_void` (matched to a bank statement line -- unmatch in reconciliation first), 409 `credit_restore_conflict` / 422 `credit_restore_unresolvable` (vendor-credit restoration cannot complete safely). Requires `purchasing:write` scope. ## OpenAPI ````yaml /openapi.yaml delete /ap-payments/{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: /ap-payments/{id}: parameters: - name: id in: path required: true schema: type: string format: uuid delete: tags: - Purchasing summary: Void an AP payment with GL reversal description: > **Authorization:** requires `purchasing:write` API-key scope AND the per-user `payments.refund_void` permission (SoD parity sweep 2026-05-16; AICPA SoD 4-role split treats AP void as highest-trust action -- manager DENIED by default). System-actor calls denied. Voids an AP payment, reversing the disbursement GL journal entry (today-dated reversal in the current open period -- closed periods are never mutated), voiding the linked check (including reversal of the check-cleared entry when the check had cleared), restoring any vendor-credit consumption to the cent, and re-opening EVERY bill the payment covered via the canonical AP balance writer. A multi-bill check payment re-opens ALL of its bills; call `GET /ap/payments/:id/void-preview` (internal UI endpoint) or inspect `void_summary` in the response to enumerate the effect. The void is reflected in the vendor's AP aging immediately. **`reason` is REQUIRED** (audited; 422 `void_reason_required` when absent). Typed rejections: 409 `payment_already_voided` (double-void), 409 `historical_row_immutable` (migrated rows), 422 `ach_payment_not_voidable` (ACH in flight or settled -- cancel at the bank / record a vendor credit instead), 422 `payment_reconciled_blocks_void` (matched to a bank statement line -- unmatch in reconciliation first), 409 `credit_restore_conflict` / 422 `credit_restore_unresolvable` (vendor-credit restoration cannot complete safely). Requires `purchasing:write` scope. operationId: voidAPPaymentV1 requestBody: required: true content: application/json: schema: type: object required: - reason properties: reason: type: string description: >- Audited void reason. Stamped into the reversal journal entries, the activity log, and the check's void_reason. responses: '200': description: >- Voided AP payment. Includes `void_summary` (reversed_journal_entry_ids, reopened_bills, restored_credits, check). content: application/json: schema: $ref: '#/components/schemas/APPayment' '401': $ref: '#/components/responses/Error' '403': $ref: '#/components/responses/Error' '404': $ref: '#/components/responses/Error' '409': $ref: '#/components/responses/Error' '422': $ref: '#/components/responses/Error' security: - ApiKeyAuth: [] components: schemas: APPayment: type: object description: A payment Arcus made to a vendor (AP-side). properties: id: type: string format: uuid object: type: string enum: - ap_payment entity_id: type: string format: uuid readOnly: true vendor_id: type: string format: uuid bill_id: type: string format: uuid nullable: true description: >- Set when payment is applied to a single bill; null for batch/on-account. batch_id: type: string format: uuid nullable: true method: type: string enum: - check - ach - wire - credit_card - cash - other amount: type: number currency: type: string default: USD reference: type: string nullable: true description: Check number, ACH trace, etc. status: type: string enum: - pending - sent - cleared - voided - returned readOnly: true payment_date: type: string format: date cleared_date: type: string format: date nullable: true notes: type: string nullable: true metadata: type: object nullable: 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. ````