> ## 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. # Get the next check number for this entity (optionally per bank account) > Returns the next available check number without reserving it. Use this to display the expected check number to the user before they initiate a check run. The actual next number is reserved and incremented when `POST /ap-payments` or `POST /printed-checks/batch-print` is called. Pass the optional `bank_account_id` query parameter to peek a specific bank account's own check sequence (per-bank numbering). When the bank has its own configured starting number the response returns that bank's next number with `per_bank_override: true`; otherwise the entity-global sequence is returned. Requires `purchasing:read` scope. ## OpenAPI ````yaml /openapi.yaml get /printed-checks/next-number 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: /printed-checks/next-number: get: tags: - Purchasing summary: Get the next check number for this entity (optionally per bank account) description: > Returns the next available check number without reserving it. Use this to display the expected check number to the user before they initiate a check run. The actual next number is reserved and incremented when `POST /ap-payments` or `POST /printed-checks/batch-print` is called. Pass the optional `bank_account_id` query parameter to peek a specific bank account's own check sequence (per-bank numbering). When the bank has its own configured starting number the response returns that bank's next number with `per_bank_override: true`; otherwise the entity-global sequence is returned. Requires `purchasing:read` scope. operationId: getNextCheckNumberV1 parameters: - name: bank_account_id in: query required: false description: >- Optional bank account UUID. When set and that bank has its own check counter, returns the bank's own next number and `per_bank_override: true`. schema: type: string format: uuid responses: '200': description: Next check number content: application/json: schema: type: object properties: data: type: object properties: next_number: type: string description: >- Formatted next check number (prefix + zero-padded value). prefix: type: string description: Check number prefix for the resolved counter. per_bank_override: type: boolean description: >- true when the number comes from the bank's own sequence, false when it is the entity-global sequence. bank_account_id: type: string format: uuid nullable: true description: >- The bank account whose sequence was used, or null for the entity-global sequence. '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. ````