## Documentation Index

Fetch the complete documentation index at: [/llms.txt](https://docs.neynar.com/llms.txt)

Use this file to discover all available pages before exploring further.

## By username

**Group:** User APIs

Use this when you need: **By username**.

## Usage

```javascript
import { NeynarAPIClient, Configuration } from "@neynar/nodejs-sdk";

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

const res = await client.lookupUserByUsername({
  username: "example", // Username of the user to fetch
  // xNeynarExperimental: true,
  // viewerFid: 123,
});
console.log(res);
```

## Parameters

| Parameter                | Type     | Required | Description                                   |
| ------------------------ | -------- | -------- | --------------------------------------------- |
| `username`              | `string` | ✅       | Username of the user to fetch                 |
| `xNeynarExperimental`    | `boolean` | ❌       | -                                             |
| `viewerFid`             | `number` | ❌       | -                                             |

## Response

Returns a `RequestArgs` object.

## Error Handling

```javascript
try {
  const res = await client.lookupUserByUsername({
    username: "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.