> ## 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. # Set recovered historical payment balance on migrated purchase orders > Order-side sibling of `vendor-bills/set-historical-balance`. On a Versa migration a settled purchase order's payment state is not always carried verbatim into the imported `orders` row, so a migrated historical PO can land showing `balance_due = NULL` or `payment_status = unpaid` even when the underlying bill was fully paid. The loader's 6.4c post-pass derives the recovered `amount_paid` / `balance_due` / `payment_status` per PO and POSTs the resolved values here so the procurement view ties to the settled truth. **GL-NEUTRAL.** A purchase order posts no journal entry of its own (the vendor bill / GRNI does). This endpoint sets the three order-level payment columns only and never posts or touches a journal entry. **Lookup key.** Each item resolves the migrated PO by `po_id` (orders.id, preferred) OR `external_id` (orders.external_id, the loader's `String(versa order_id)` fallback). **Strict provenance.** Only rows with `document_type = 'purchase_order'` AND `external_source = 'versa_cloud'` AND `is_historical_import = true` are touched. No live operator PO is ever modified. **Clamp.** `amount_paid` is clamped to `order_total`; `balance_due = max(0, order_total - amount_paid)`; `payment_status` is recomputed (`paid` / `partial` / `unpaid`) from the clamped numbers. **Idempotent.** An already-at-target PO (within a cent + same status) returns `set=false` (no-op). Re-running the whole pass is safe. **Scope:** `migration:write`. Max 500 items per call. ## OpenAPI ````yaml /openapi.yaml post /entities/{entity_id}/migration/purchase-orders/set-historical-balance 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: /entities/{entity_id}/migration/purchase-orders/set-historical-balance: post: tags: - Migration summary: Set recovered historical payment balance on migrated purchase orders description: > Order-side sibling of `vendor-bills/set-historical-balance`. On a Versa migration a settled purchase order's payment state is not always carried verbatim into the imported `orders` row, so a migrated historical PO can land showing `balance_due = NULL` or `payment_status = unpaid` even when the underlying bill was fully paid. The loader's 6.4c post-pass derives the recovered `amount_paid` / `balance_due` / `payment_status` per PO and POSTs the resolved values here so the procurement view ties to the settled truth. **GL-NEUTRAL.** A purchase order posts no journal entry of its own (the vendor bill / GRNI does). This endpoint sets the three order-level payment columns only and never posts or touches a journal entry. **Lookup key.** Each item resolves the migrated PO by `po_id` (orders.id, preferred) OR `external_id` (orders.external_id, the loader's `String(versa order_id)` fallback). **Strict provenance.** Only rows with `document_type = 'purchase_order'` AND `external_source = 'versa_cloud'` AND `is_historical_import = true` are touched. No live operator PO is ever modified. **Clamp.** `amount_paid` is clamped to `order_total`; `balance_due = max(0, order_total - amount_paid)`; `payment_status` is recomputed (`paid` / `partial` / `unpaid`) from the clamped numbers. **Idempotent.** An already-at-target PO (within a cent + same status) returns `set=false` (no-op). Re-running the whole pass is safe. **Scope:** `migration:write`. Max 500 items per call. operationId: postMigrationPurchaseOrderSetHistoricalBalance parameters: - name: entity_id in: path required: true schema: type: string format: uuid - name: Idempotency-Key in: header required: false schema: type: string description: > Optional idempotency key. If supplied, retrying the same call within 24 hours returns the previous result. requestBody: required: true content: application/json: schema: type: object required: - items properties: items: type: array maxItems: 500 items: type: object required: - amount_paid - balance_due properties: po_id: type: string format: uuid description: Arcus orders.id of the migrated PO (preferred key). external_id: type: string description: >- orders.external_id (Versa order id) -- fallback key when po_id is absent. amount_paid: type: number description: Recovered LEAST(recovered_paid, order_total). balance_due: type: number description: GREATEST(order_total - recovered_paid, 0). payment_status: type: string enum: - unpaid - partial - paid description: >- Recovered payment status (recomputed defensively from amount_paid/balance_due). examples: batch: summary: Set recovered balances on a batch of migrated POs value: items: - external_id: '44895' amount_paid: 1250 balance_due: 0 payment_status: paid - po_id: 6b1e9a4f-1d2c-4f8e-9c8a-8b1d2e3f4a5b amount_paid: 500 balance_due: 250 payment_status: partial responses: '200': description: PO historical-balance result content: application/json: schema: type: object properties: object: type: string example: migration_po_historical_balance_result total: type: integer updated: type: integer already_correct: type: integer not_found: type: integer failed: type: integer results: type: array items: type: object '400': $ref: '#/components/responses/Error' '401': $ref: '#/components/responses/Error' '403': $ref: '#/components/responses/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: 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. ````