> ## Documentation Index
> Fetch the complete documentation index at: https://docs.neynar.com/llms.txt
> Use this file to discover all available pages before exploring further.

# checkDomainAvailability

Check if a custom subdomain is available

> **Group:** Studio APIs

Use this when you need: **Check if a custom subdomain is available**.

## Usage

```ts theme={"system"}
import { NeynarAPIClient, Configuration } from "@neynar/nodejs-sdk";

const client = new NeynarAPIClient(
  new Configuration({ apiKey: "YOUR_NEYNAR_API_KEY" })
);

const res = await client.checkDomainAvailability({
  fid: 123, // Farcaster ID of the requesting user
  subdomain: "example", // The desired subdomain (without .neynar.app suffix). Must be 3-63 characters, lowercase alphanumeric and hyphens only.
});
console.log(res);
```

## Parameters

| Parameter   | Type     | Required | Description                                                                                                           |
| ----------- | -------- | :------: | --------------------------------------------------------------------------------------------------------------------- |
| `fid`       | `number` |     ✅    | Farcaster ID of the requesting user                                                                                   |
| `subdomain` | `string` |     ✅    | The desired subdomain (without .neynar.app suffix). Must be 3-63 characters, lowercase alphanumeric and hyphens only. |

## Response

Returns a `RequestArgs` object.

## Error Handling

```ts theme={"system"}
try {
  const res = await client.checkDomainAvailability({
    fid: 123,
    subdomain: "example"
  });
  // use res
} catch (err) {
  // Axios/HTTP errors, invalid params, auth issues, etc.
  console.error(err);
}
```

## Tips

* Provide a **viewerFid** when supported to respect mutes/blocks and include `viewer_context`.
* Keep requests scoped (e.g., use `limit`) to improve latency.
* Cache results where sensible.