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

# Rate Limiting

> Configure rate limiting with Redis

## Overview

Guardian API supports optional rate limiting using Redis (Upstash compatible). Rate limiting helps prevent API abuse and ensures fair usage.

## Setup

### 1. Create Upstash Redis Database

1. Create a free account at [Upstash](https://upstash.com)
2. Create a new Redis database
3. Copy the Redis URL from your dashboard

### 2. Configure Environment

Add to `backend/.env`:

```bash theme={null}
REDIS_URL=rediss://default:<your-token>@<your-host>:6379
```

### 3. Restart API

```bash theme={null}
cd backend
uvicorn app.main:app --reload
```

Rate limiting is now active!

## Default Limits

| Limit Type          | Default Value  |
| ------------------- | -------------- |
| **Requests per IP** | 100 per minute |
| **Window**          | 60 seconds     |

## Behavior

### When Limit Exceeded

**Response Code**: 429 Too Many Requests

**Response Body**:

```json theme={null}
{
  "detail": "Rate limit exceeded. Try again later."
}
```

### Fail-Open Design

If Redis is unavailable:

* API continues to work
* Rate limiting is temporarily disabled
* Warning logged but requests succeed

<Info>
  This fail-open design ensures the API remains available even if Redis has issues.
</Info>

## Custom Rate Limits

To customize rate limits, modify `backend/app/core/rate_limit.py`:

```python theme={null}
# Example: Increase limit to 200 requests per minute
async def check_rate_limit(request: Request):
    # ... existing code ...
    limit = 200  # Increased from 100
    window = 60  # seconds
    # ... rest of implementation ...
```

## Monitoring

Check rate limit usage by monitoring Redis:

```bash theme={null}
# Connect to Redis
redis-cli -u $REDIS_URL

# Check rate limit keys
KEYS rate_limit:*

# Get count for specific IP
GET rate_limit:192.168.1.1
```

## Disable Rate Limiting

To disable rate limiting, simply don't set `REDIS_URL` in your `.env` file or remove it entirely.

## See Also

* [Environment Variables](/configuration/environment) - All configuration options
* [Installation](/installation) - Setup guide