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

# Authentication

> How to authenticate against the Arrays API — API Key or Nanopayment.

Arrays supports **two authentication modes**.

## 1. API Key (recommended for most users)

Send your key in the `X-API-Key` header.

<Tabs>
  <Tab title="cURL">
    ```bash theme={null}
    curl "https://data-tools.prd.arrays.org/api/v1/stocks/company/detail?symbol=AAPL" \
      -H "X-API-Key: $ARRAYS_API_KEY"
    ```
  </Tab>

  <Tab title="Python">
    ```python theme={null}
    import requests, os
    r = requests.get(
        "https://data-tools.prd.arrays.org/api/v1/stocks/company/detail",
        headers={"X-API-Key": os.environ["ARRAYS_API_KEY"]},
        params={"symbol": "AAPL"},
    )
    ```
  </Tab>

  <Tab title="Node.js">
    ```javascript theme={null}
    const res = await fetch(
      "https://data-tools.prd.arrays.org/api/v1/stocks/company/detail?symbol=AAPL",
      { headers: { "X-API-Key": process.env.ARRAYS_API_KEY } }
    );
    ```
  </Tab>
</Tabs>

### Get a key

1. Sign up at [arrays.org](https://arrays.org) (email, Google, or GitHub)
2. Copy the key from your Dashboard — visible immediately
3. Store in env / secret manager — never commit to git

### Security best practices

<Warning>
  * Never expose your API key in client-side code (browser, mobile, public Cursor rules).
  * Use a backend proxy if you need to call Arrays from a browser app.
  * Rotate keys regularly from the Dashboard.
  * Use separate keys for dev / staging / prod.
</Warning>

## 2. Nanopayment (no key, pay-per-call)

For crypto endpoints, you can skip the API key entirely and pay per call in USDC.

[Full Nanopayment guide →](/nanopayment/overview)

```typescript theme={null}
import { wrapFetchWithPayment } from "x402-fetch";

const fetchWithPayment = wrapFetchWithPayment(fetch, walletClient);
const res = await fetchWithPayment(
  "https://data-tools.prd.arrays.org/api/v1/crypto/funding-rate?symbol=BTCUSDT"
);
```