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Werk #17867: REST API: Manage custom host attributes

Component REST API
Title REST API: Manage custom host attributes
Date May 11, 2026
Level Trivial Change
Class New Feature
Compatibility Compatible - no manual interaction needed
Checkmk versions & editions
3.0.0b1
Not yet released
Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

You can now manage custom host attributes via the REST API. This includes listing all attributes, retrieving a single attribute, creating new attributes, updating existing ones, and deleting them — under the new Custom host attributes endpoint family.

Until now, custom host attributes could only be created and managed through the Setup UI under Hosts → Related → Custom host attributes.

The managed fields mirror the Add host attribute form in Setup: an internal name (set at creation and immutable thereafter), a human-readable title, a topic which the attribute is grouped under when editing a host, an optional help text shown next to the field, and two boolean flags: show_in_table (whether the attribute appears in host overview tables) and add_custom_macro (whether the attribute is exposed as a macro in check commands and notifications).

The full request and response schemas are available in the embedded API documentation at Help → REST API → Documentation.

Access and permissions

The read endpoints (list, show) require the Manage custom attributes permission (wato.custom_attributes). Write operations (create, update, delete) additionally require Make changes, perform actions (wato.edit), consistent with all other Setup endpoints.

Immutable name

The name field serves as the internal identifier for a custom host attribute and cannot be changed after creation. To rename an attribute, delete the old one and create a new one with the desired name. This matches the behavior of the Setup UI, which also prevents renaming.

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