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

# Authentication

> Authenticate the ParlayX TypeScript SDK with your API key

Every request is authenticated with your API key, sent as the `x-api-key`
header. `createClient` wires this in once — create a client and reuse it for
every call.

```ts theme={null}
import { createClient } from "@parlayx/sdk";

const client = createClient({ apiKey: process.env.PARLAYX_API_KEY! });
```

Get your API key from the [console](https://console.parlayx.com/). Keep it
secret — load it from an environment variable or secret manager rather than
committing it to source control.

The client targets the production API. Reuse a single instance across your
application.