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

# Check username availability

> Check whether a username is available before setting it

## Overview

`useCheckUsernameAvailability` returns a function that checks whether a given username is available in the project. Use this to validate a username in real time before calling `updateUser`.

## Usage Example

```tsx theme={null}
import { useCheckUsernameAvailability } from "@replyke/react-js";
import { useState } from "react";

function UsernameInput() {
  const checkAvailability = useCheckUsernameAvailability();
  const [available, setAvailable] = useState<boolean | null>(null);

  const handleChange = async (username: string) => {
    if (username.length < 3) return;
    const result = await checkAvailability({ username });
    setAvailable(result.available);
  };

  return (
    <div>
      <input onChange={(e) => handleChange(e.target.value)} />
      {available === true && <span>Available</span>}
      {available === false && <span>Taken</span>}
    </div>
  );
}
```

## Parameters

The hook returns a function. That function accepts:

<ParamField path="username" type="string" required>
  The username to check.
</ParamField>

## Returns

<ResponseField name="available" type="boolean">
  `true` if the username is available, `false` if it is already taken.
</ResponseField>