---
title: "Cheap existence + freshness probe"
method: HEAD
path: "/json/{boardId}"
tags: ["AI-facing"]
---

# Cheap existence + freshness probe

`HEAD /json/{boardId}`

## Request

- Base URL: `https://cnvs.app`
- URL: `https://cnvs.app/json/{boardId}`
- Auth: none declared

Same headers as `GET /json/{boardId}` but zero body. Returns 200 with ETag if the board exists, 404 otherwise.

## Response `200`

Board exists; ETag returned.

## Other responses

- `404`: Board does not exist or was deleted within the 30-day tombstone window.

---

[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)