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

# Authentication

> Authenticate API requests with your API key.

Authenticate requests by including your API key in the `X-API-Key` header.
Generate API keys from your [dashboard](https://probsights.com/dashboard).

```bash theme={null}
curl -H "X-API-Key: YOUR_API_KEY" \
  "https://api.probsights.com/search/series?q=15m"
```

```python theme={null}
import requests

response = requests.get(
    "https://api.probsights.com/search/series",
    headers={"X-API-Key": "YOUR_API_KEY"},
    params={"q": "15m"},
)
print(response.json())
```

The interactive **Try** playground on each API reference page uses the same
`X-API-Key` header. Paste your key once in the playground auth panel.

## Endpoint access by plan

| Endpoint group  | Required plan    |
| --------------- | ---------------- |
| Search          | Free             |
| Historical data | Free             |
| Whale tracking  | Pro              |
| Arbitrage       | Builder / Trader |
| Price spreads   | Builder / Trader |

Keep your API key confidential. Do not expose it in client-side code or public
repositories.

Requests with invalid credentials receive **401**. Requests that exceed your
plan's endpoint access receive **403**.