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

# Check Username Availability

> Check if a username is available for use

## Endpoint

```
profile.checkUsername
```

Checks whether a username is available. Returns `true` if the username is available or already belongs to the authenticated user.

## Authentication

Requires authentication via session cookie.

## Request

<ParamField name="username" type="string" required>
  Username to check (3-39 characters, lowercase letters, numbers, and hyphens only)
</ParamField>

## Response

<ResponseField name="available" type="boolean" required>
  `true` if the username is available or belongs to the current user, `false` if taken by another user
</ResponseField>

## Example

```typescript theme={null}
import { client } from '@/lib/client';

const result = await client.profile.checkUsername({
  username: "johndoe"
});

console.log(result);
// { available: true }
```

## Schema

```typescript theme={null}
const usernameSchema = z
  .string()
  .min(3, "Username must be at least 3 characters")
  .max(39, "Username must be at most 39 characters")
  .regex(
    /^[a-z0-9](?:[a-z0-9-]*[a-z0-9])?$/,
    "Lowercase letters, numbers, and hyphens only. Must start and end with a letter or number."
  )
  .refine((val) => !val.includes("--"), "Username cannot contain consecutive hyphens")
  .refine((val) => !RESERVED_USERNAMES.has(val), "This username is reserved");
```

## Notes

* Username is automatically converted to lowercase before checking
* Returns `true` if the username belongs to the authenticated user (useful for validation during profile updates)
* Username must pass validation rules (no reserved words, valid format)

## Source

* Schema: `lib/schema.ts:16`
* Implementation: `server/procedures/profile.ts:65`
* Router: `server/router.ts:47`