---
title: "Assign or clear a thread's category"
method: PUT
path: "/v3/inbox/threads/{id}/category"
tags: ["Inbox"]
---

# Assign or clear a thread's category

`PUT /v3/inbox/threads/{id}/category`

<small>_Requires the `inbox:operate` scope (or a broader one that includes it)._</small>

Sets the thread's category, or clears it when `categoryId` is `null`. Idempotent.

## Path parameters

- `id` integer, required

## Request body

- object — Assign or clear a category on a thread.
  - `categoryId` integer, nullable — Target category id, or `null` to clear the assignment.

## Response `204`

Category set

- object

## Other responses

- `400` — Route/body validation failure, or a business-rule rejection.
- `401` — Unauthorized. The response body is empty; check the `WWW-Authenticate` header for the expected scheme.
- `403` — Inbox feature is not available for this user or team.
- `404` — Thread or category not found.
- `429` — Too Many Requests

---

[API](https://skmtc.dev/reply/apis/reply-api.md) · [All operations](https://skmtc.dev/reply/apis/reply-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/reply/reply-api/revisions/1c3d32eaf95e/schema)