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

# API Overview

> Introduction to the Helicone REST API

## Base URL

The Helicone API is available at:

```
https://api.helicone.ai
```

All API endpoints are relative to this base URL.

## API Structure

The Helicone API follows RESTful conventions and is organized into versioned endpoints:

* **v1** - Current stable API version
  * `/v1/request` - Query and manage requests
  * `/v1/api-keys` - Manage API keys and provider keys
  * `/v1/webhooks` - Configure webhooks
  * `/v1/models` - Access model information
  * `/v1/evals` - Manage evaluations
  * And more...

## Request Format

All requests to the Helicone API must:

1. Use HTTPS
2. Include proper authentication headers (see [Authentication](/api/authentication))
3. Send JSON payloads for POST/PUT requests with `Content-Type: application/json`

### Example Request

```bash theme={null}
curl https://api.helicone.ai/v1/request/query \
  -X POST \
  -H "Authorization: Bearer YOUR_HELICONE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "filter": {},
    "limit": 10,
    "offset": 0,
    "sort": {
      "created_at": "desc"
    }
  }'
```

## Response Format

API responses are returned as JSON with a consistent structure:

### Success Response

```json theme={null}
{
  "data": [...],
  "error": null
}
```

### Error Response

```json theme={null}
{
  "data": null,
  "error": "Error message describing what went wrong"
}
```

### HTTP Status Codes

| Status Code | Description                                      |
| ----------- | ------------------------------------------------ |
| 200         | Success                                          |
| 201         | Created/Success for mutations                    |
| 400         | Bad Request - Invalid parameters                 |
| 401         | Unauthorized - Missing or invalid authentication |
| 500         | Internal Server Error                            |

## Pagination

Many API endpoints support pagination using `offset` and `limit` parameters:

```json theme={null}
{
  "filter": {},
  "offset": 0,
  "limit": 10
}
```

* **offset** - Number of records to skip (default: 0)
* **limit** - Maximum number of records to return (default: 10)

To retrieve the next page, increment the offset by the limit value:

```json theme={null}
{
  "offset": 10,
  "limit": 10
}
```

## Filtering and Sorting

Query endpoints support flexible filtering and sorting:

### Filter Structure

```json theme={null}
{
  "filter": {
    "left": {
      "request_response_rmt": {
        "model": {
          "equals": "gpt-4"
        }
      }
    },
    "operator": "and",
    "right": {
      "request_response_rmt": {
        "status": {
          "equals": 200
        }
      }
    }
  }
}
```

### Sort Structure

```json theme={null}
{
  "sort": {
    "created_at": "desc"
  }
}
```

## Rate Limits

The Helicone API implements rate limiting to ensure fair usage:

* Rate limits vary by endpoint and subscription tier
* Rate limit information is included in response headers
* When rate limited, you'll receive a 429 status code

<Note>
  For specific rate limits on your account, check your organization settings or contact support.
</Note>

## Next Steps

<CardGroup cols={2}>
  <Card title="Authentication" icon="key" href="/api/authentication">
    Learn how to authenticate API requests
  </Card>

  <Card title="API Reference" icon="code" href="/api-reference/introduction">
    Explore detailed endpoint documentation
  </Card>
</CardGroup>