---
title: "Get a field definition by ID"
method: GET
path: "/api/cases/field_definitions/{field_definition_id}"
tags: ["cases"]
---

# Get a field definition by ID

`GET /api/cases/field_definitions/{field_definition_id}`

**Spaces method and path for this operation:**

<div><span class="operation-verb get">get</span>&nbsp;<span class="operation-path">/s/{space_id}/api/cases/field_definitions/{field_definition_id}</span></div>

Refer to [Spaces](https://www.elastic.co/docs/deploy-manage/manage-spaces) for more information.

Returns a single field definition by its ID. Requires the Cases feature to be enabled in the space.

## Path parameters

- `field_definition_id` string, required

## Response `200`

Indicates a successful call. Returns the field definition.

- CasesFieldDefinitionResponse — A field definition from the field library. The `legacyKey` attribute, which is a server-managed link to a migrated custom field, is not included in the public API response.
  - `definition` string, required — The field definition as a YAML string. New definitions are limited to 30 000 characters, but existing definitions created via internal tooling may be longer.
  - `description` string — Optional human-readable description of the field's purpose.
  - `displayOrder` integer — Position of a global field in the case details view. Assigned by the server and changed via the Field Library reorder controls.
  - `fieldDefinitionId` string, required — Unique server-assigned identifier for the field definition (UUID). May be UUIDv4 for definitions created through the public API, or UUIDv5 for definitions created by internal migration processes.
  - `isGlobal` boolean — When true, this field is rendered in every case regardless of which template the case uses.
  - `name` string, required — The field name. Must match the `name` property in the YAML definition and is unique per owner (case-insensitive). Immutable after creation.
  - `owner` string, required — The application that owns this field definition.

## Other responses

- `401` — Authorization information is missing or invalid.
- `403` — The user does not have permission to read field definitions for the owner.
- `404` — The field definition was not found.

---

[API](https://skmtc.dev/elastic/apis/kibana-apis.md) · [All operations](https://skmtc.dev/elastic/apis/kibana-apis/llms.txt) · [OpenAPI document](https://skmtc.dev/elastic/apis/kibana-apis/revisions/84f30e7da461?raw)