---
title: "Reserve Ar Ids"
method: POST
path: "/registration/reserve"
tags: ["register"]
---

# Reserve Ar Ids

`POST /registration/reserve`

## Request

- Base URL: `https://anchorregistry.com` (the document declares no server; this is the origin it was published from)
- URL: `https://anchorregistry.com/registration/reserve`
- Auth: none declared

Pre-generate AR-IDs before payment so the client can compute:
  treeId          = keccak256(K ‖ rootArId)
  tokenCommitment = keccak256(K ‖ arId)
Both are computed client-side and passed through to the contract.
K (the Anchor Key, 32 random bytes) is never transmitted to this server.
See ar-ui/app/register/confirm/page.tsx for the exact construction
and the paper spec (anchorregistry_gt.pdf §4.2).

## Query parameters

- `count` integer

## Response `200`

Successful Response

- unknown

## Other responses

- `422`: Validation Error

---

[API](https://skmtc.dev/anchorregistry/apis/anchorregistry-api.md) · [All operations](https://skmtc.dev/anchorregistry/apis/anchorregistry-api/llms.txt) · [OpenAPI document](https://skmtc.dev/anchorregistry/apis/anchorregistry-api/revisions/73ff7877dda3?raw)