---
title: "Set application theme assignment"
method: PATCH
path: "/clusters/{cluster_id}/realms/{realm}/applications/{client_id}/themes"
tags: ["Themes"]
---

# Set application theme assignment

`PATCH /clusters/{cluster_id}/realms/{realm}/applications/{client_id}/themes`

## Request

- Base URL: `http://localhost:8000`
- URL: `http://localhost:8000/clusters/{cluster_id}/realms/{realm}/applications/{client_id}/themes`
- Auth: API key in header `API-Key`

Assigns a deployed custom login theme to the application client. Setting `login` to `null` resets the client to the realm default.

Required scope: `themes:write`

## Path parameters

- `cluster_id` string, uuid, required
- `realm` string, required: Keycloak realm name (not ID). Must start with a letter; allows letters, digits, and hyphens.
- `client_id` string, required: OAuth 2.0 client identifier. Used as the stable resource identifier in this API and in Keycloak realm URLs.

## Headers

- `API-Version` '2026-06-01.beta', required

## Request body

- SetClientThemeAssignmentRequest
  - `login` string, uuid, required

## Response `200`

The request has succeeded.

- ClientThemeAssignment: Which custom theme is active for a Keycloak application client.
  - `login` string, uuid, required

## Other responses

- `400`: The server could not understand the request due to invalid syntax.
- `401`: Access is unauthorized.
- `403`: Access is forbidden.
- `404`: The server cannot find the requested resource.
- `409`: The target cluster is temporarily unavailable because an update or maintenance operation is in progress. The request was not applied and can be retried once the cluster returns to the available state; the Retry-After header carries a suggested delay in seconds.
- `422`: Client error
- `429`: Client error
- `500`: Server error
- `501`: Server error

---

[API](https://skmtc.dev/skycloak/apis/skycloak-public-api.md) · [All operations](https://skmtc.dev/skycloak/apis/skycloak-public-api/llms.txt) · [OpenAPI document](https://skmtc.dev/skycloak/apis/skycloak-public-api/revisions/33a69e2ce35f?raw)