> ## 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.

# Create a note

> Creates a note attached to any resource. `parent_type` + `parent_id` are
required. `entity_id` is derived from the API key.




## OpenAPI

````yaml /openapi.yaml post /notes
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_<code>_<random>` (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:
  /notes:
    post:
      tags:
        - Notes
      summary: Create a note
      description: |
        Creates a note attached to any resource. `parent_type` + `parent_id` are
        required. `entity_id` is derived from the API key.
      operationId: createNoteV1
      parameters:
        - $ref: '#/components/parameters/IdempotencyKey'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
                - parent_type
                - parent_id
                - body
              properties:
                parent_type:
                  type: string
                parent_id:
                  type: string
                  format: uuid
                body:
                  type: string
                is_pinned:
                  type: boolean
      responses:
        '201':
          description: Note created
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: object
      security:
        - ApiKeyAuth:
            - notes:write
components:
  parameters:
    IdempotencyKey:
      name: Idempotency-Key
      in: header
      required: false
      description: |
        Client-generated unique key for idempotent POST/PATCH/DELETE operations.
        Alias for the Idempotency parameter. Max 255 chars. On retry with the
        same key, the original response is returned without re-executing the
        operation. Keys expire after 24 hours.
      schema:
        type: string
        maxLength: 255
  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_<code>_<random>
        Test keys use ark_test_ent_<code>_<random>. Both are issued per entity
        via Settings > Developers > API Keys.

````