---
title: "Set the shared kanban column width"
method: POST
path: "/api/boards/{boardId}/column-width"
tags: ["Kanban"]
---

# Set the shared kanban column width

`POST /api/boards/{boardId}/column-width`

## Request

- Base URL: `https://cnvs.app`
- URL: `https://cnvs.app/api/boards/{boardId}/column-width`
- Auth: none declared

Board-level setting: the pixel width every kanban column shares. Only valid on a `todo`-mode board. Mirrors the WebSocket `set_column_width` frame and the MCP `set_column_width` tool; exists mainly so a snapshot restore can recreate the saved width. The value is clamped server-side to the [200, 480]px range. Read the current value as `colWidth` from `GET /json/{id}`.

## Request body

- object
  - `width` number, required: Column width in px. Clamped to [200, 480].

## Response `200`

Width set (after clamping).

- object
  - `ok` boolean, required
  - `width` number, required

## Other responses

- `400`: Invalid input (missing or malformed board id).
- `401`: Board is access-locked and the request did not carry a valid key. `lockMode` tells the client whether to prompt for a code or just disable write UI.
- `404`: Board does not exist or was deleted within the 30-day tombstone window.
- `429`: Rate limit exceeded. Standard REST/MCP: 60 requests/10s/board; valid X-Import-Token infrastructure tier: 600/10s/board; browser WebSocket always 60/10s/board. REST/MCP enforcement is soft per-isolate; WebSocket enforcement is strong per Durable Object.

---

[API](https://skmtc.dev/cnvs/apis/cnvs-app-http-api.md) · [All operations](https://skmtc.dev/cnvs/apis/cnvs-app-http-api/llms.txt) · [OpenAPI document](https://skmtc.dev/cnvs/apis/cnvs-app-http-api/revisions/c8f2c3b7ff90?raw)