## vLLM Documentation

vLLM is a high-performance inference engine for large language models that provides significant performance improvements for local inference. It’s designed to maximize throughput and memory efficiency for serving LLMs.

## Prerequisites

1. **Install vLLM**:
   
   ```
   pip install vllm
   ```

2. **Start vLLM server**:
   
   ```
   # For testing with a small model
   vllm serve microsoft/DialoGPT-medium --port 8000

# For production with a larger model (requires GPU)
   vllm serve Qwen/Qwen2.5-32B-Instruct --port 8000
   ```

## Usage

### Python
   
```python
import os
from mem0 import Memory

os.environ["OPENAI_API_KEY"] = "your-api-key"  # used for embedding model

config = {
    "llm": {
        "provider": "vllm",
        "config": {
            "model": "Qwen/Qwen2.5-32B-Instruct",
            "vllm_base_url": "http://localhost:8000/v1",
            "temperature": 0.1,
            "max_tokens": 2000,
        }
    }
}

m = Memory.from_config(config)
messages = [
    {"role": "user", "content": "I'm planning to watch a movie tonight. Any recommendations?"},
    {"role": "assistant", "content": "How about thriller movies? They can be quite engaging."},
    {"role": "user", "content": "I'm not a big fan of thrillers, but I love sci-fi movies."},
    {"role": "assistant", "content": "Got it! I'll avoid thrillers and suggest sci-fi movies instead."}
]
m.add(messages, user_id="alice", metadata={"category": "movies"})
```

### TypeScript
   
```javascript
import { Memory } from "mem0ai/oss";

const config = {
  llm: {
    provider: "vllm",
    config: {
      model: "Qwen/Qwen2.5-32B-Instruct",
      baseURL: "http://localhost:8000/v1",
      apiKey: process.env.VLLM_API_KEY || "vllm-api-key",
      temperature: 0.1,
      maxTokens: 2000,
    },
  },
};

const memory = new Memory(config);
const messages = [
  {
    role: "user",
    content: "I'm planning to watch a movie tonight. Any recommendations?",
  },
  {
    role: "assistant",
    content: "How about thriller movies? They can be quite engaging.",
  },
  {
    role: "user",
    content: "I'm not a big fan of thrillers, but I love sci-fi movies.",
  },
  {
    role: "assistant",
    content: "Got it! I'll avoid thrillers and suggest sci-fi movies instead.",
  },
];
await memory.add(messages, { userId: "alice", metadata: { category: "movies" } });
```

## Configuration Parameters

| Parameter          | Description                        | Default                          | Environment Variable |
| ------------------ | ---------------------------------- | -------------------------------- | --------------------- |
| `model`            | Model name running on vLLM server | `"Qwen/Qwen2.5-32B-Instruct"` | -                     |
| `vllm_base_url`   | vLLM server URL                   | `"http://localhost:8000/v1"` | `VLLM_BASE_URL`      |
| `api_key`         | API key (dummy for local)        | `"vllm-api-key"`            | `VLLM_API_KEY`       |
| `temperature`      | Sampling temperature               | `0.1`                          | -                     |
| `max_tokens`      | Maximum tokens to generate        | `2000`                         | -                     |

## Environment Variables

You can set these environment variables instead of specifying them in config:

```bash
export VLLM_BASE_URL="http://localhost:8000/v1"
export VLLM_API_KEY="your-vllm-api-key"
export OPENAI_API_KEY="your-openai-api-key"  # for embeddings
```

## Benefits

- **High Performance**: 2-24x faster inference than standard implementations
- **Memory Efficient**: Optimized memory usage with PagedAttention
- **Local Deployment**: Keep your data private and reduce API costs
- **Easy Integration**: Drop-in replacement for other LLM providers
- **Flexible**: Works with any model supported by vLLM

## Troubleshooting

1. **Server not responding**: Make sure vLLM server is running
   ```bash
   curl http://localhost:8000/health
   ```
2. **404 errors**: Ensure correct base URL format
   ```bash
   "vllm_base_url": "http://localhost:8000/v1"  # Note the /v1
   ```
3. **Model not found**: Check model name matches server
4. **Out of memory**: Try smaller models or reduce `max_model_len`
   ```bash
   vllm serve Qwen/Qwen2.5-32B-Instruct --max-model-len 4096
   ```

## Config

All available parameters for the `vllm` config are present in the [Master List of All Params in Config](https://docs.mem0.ai/components/llms/config).