---
title: "Check domain availability"
method: GET
path: "/api/apps/{app_id}/custom-domains/availability"
---

# Check domain availability

`GET /api/apps/{app_id}/custom-domains/availability`

<Info>This API is in beta. Endpoints, fields, and behavior may still change, so avoid depending on it in production.</Info>

Checks whether a domain can be registered through Base44, and suggests similar ones.

The first entry in `results` is always the domain you asked about, followed by up to five suggestions. A premium domain, or one containing a social media platform's name, comes back as unavailable because Base44 can't sell it.

The check asks Wix, so it fails while Wix's domain search is unavailable. Retrying later is safe.

Checking is limited to 12 requests a minute per caller. Some workspaces have a different limit.

## Path parameters

- `app_id` string, required — ID of the app you're finding a domain for.

## Query parameters

- `domain` string, required — Domain to check, such as `example.com`.

## Response `200`

Successful Response

- DomainAvailabilityCheck — Whether a domain can be registered, with similar domains that can.
  - `query` string, required — The domain you asked about, normalized to lower case.
  - `results` DomainAvailabilityCheckResult[], required — The domain you asked about, first, followed by up to five suggestions.
    - `domain` string, required — The domain this entry is about.
    - `available` boolean, required — Whether Base44 can register the domain (`true`) or not (`false`).
    - `reason` 'premium' | 'unavailable', nullable — Why the domain can't be registered, or `null` when it can. Either `premium`, a premium-priced domain Base44 doesn't sell, or `unavailable` for every other reason.

## Other responses

- `400` — `domain` isn't a valid domain name.
- `401` — Missing or invalid credentials.
- `403` — You don't have access to this app, or you used a workspace API key. These endpoints take a personal API key.
- `404` — App not found.
- `422` — Validation Error
- `429` — Rate limit reached. Retry later.

## Changes

- **2026-09-24** `eb89d67965ff` — 1 info
  - endpoint added

[Change history](https://skmtc.dev/base44/apis/base44-app-management-api/changes/api/apps/:app_id/custom-domains/availability/get.md)

---

[API](https://skmtc.dev/base44/apis/base44-app-management-api.md) · [All operations](https://skmtc.dev/base44/apis/base44-app-management-api/llms.txt) · [OpenAPI document](https://skmtc.dev/base44/apis/base44-app-management-api/revisions/5e69adeb8667?raw)