---
title: "Request a reservation"
method: POST
path: "/v2/on-demand/request-reservation"
---

# Request a reservation

`POST /v2/on-demand/request-reservation`

Request a reservation for a large instance

## Request body

- object
  - `gpuCount` number, required

## Response `200`

Successful response

- object
  - `message` string, required

## Other responses

- `400` — Invalid input data
- `401` — Authorization not provided
- `403` — Insufficient access
- `500` — Internal server error

## Changes

- **2026-09-03** `c5ba6c2504bb` — 1 info
  - endpoint added

[Change history](https://skmtc.dev/hyperbolic/apis/castle-api/changes/v2/on-demand/request-reservation/post.md)

---

[API](https://skmtc.dev/hyperbolic/apis/castle-api.md) · [All operations](https://skmtc.dev/hyperbolic/apis/castle-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/hyperbolic/castle-api/revisions/c5ba6c2504bb/schema)