> ## Documentation Index
> Fetch the complete documentation index at: https://docs.oddpool.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 [account settings](https://oddpool.com/account).

```bash theme={null}
curl -H "X-API-Key: oddpool_your_api_key" \
  "https://api.oddpool.com/whales/user/events"
```

## Endpoint access by plan

| Endpoint group  | Required plan | Price                                          |
| --------------- | ------------- | ---------------------------------------------- |
| Search          | Free          | Free                                           |
| Historical data | Free          | Free                                           |
| WebSocket feeds | Free+         | Free (dist only), Pro+ for book/trade/snapshot |
| Whale tracking  | Pro           | 30/mo                                          |
| Arbitrage       | Premium       | 100/mo                                         |
| Price spreads   | Premium       | 100/mo                                         |

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

Requests with invalid or expired credentials receive a `401` (invalid key) or `403` (insufficient tier) response.