<p align="center">
  <img src="assets/logo-text.png" alt="LEANN Logo" width="400">
</p>

<p align="center">
  <img src="https://img.shields.io/badge/Python-3.9%2B-blue.svg" alt="Python 3.9+">
  <img src="https://img.shields.io/badge/License-MIT-green.svg" alt="MIT License">
  <img src="https://img.shields.io/badge/Platform-Linux%20%7C%20macOS-lightgrey" alt="Platform">
</p>

<h2 align="center" tabindex="-1" class="heading-element" dir="auto">
    The smallest vector index in the world. RAG Everything with LEANN!
</h2>

LEANN is an innovative vector database that democratizes personal AI. Transform your laptop into a powerful RAG system that can index and search through millions of documents while using **97% less storage** than traditional solutions **without accuracy loss**.

LEANN achieves this through *graph-based selective recomputation* with *high-degree preserving pruning*, computing embeddings on-demand instead of storing them all. [Illustration Fig →](#️-architecture--how-it-works) | [Paper →](https://arxiv.org/abs/2506.08276)

**Ready to RAG Everything?** Transform your laptop into a personal AI assistant that can search your **[file system](#-personal-data-manager-process-any-documents-pdf-txt-md)**, **[emails](#-your-personal-email-secretary-rag-on-apple-mail)**, **[browser history](#-time-machine-for-the-web-rag-your-entire-browser-history)**, **[chat history](#-wechat-detective-unlock-your-golden-memories)**, or external knowledge bases (i.e., 60M documents) - all on your laptop, with zero cloud costs and complete privacy.



## Why LEANN?

<p align="center">
  <img src="assets/effects.png" alt="LEANN vs Traditional Vector DB Storage Comparison" width="70%">
</p>

> **The numbers speak for themselves:** Index 60 million Wikipedia chunks in just 6GB instead of 201GB. From emails to browser history, everything fits on your laptop. [See detailed benchmarks for different applications below ↓](#storage-comparison)


🔒 **Privacy:** Your data never leaves your laptop. No OpenAI, no cloud, no "terms of service".

🪶 **Lightweight:** Graph-based recomputation eliminates heavy embedding storage, while smart graph pruning and CSR format minimize graph storage overhead. Always less storage, less memory usage!

📦 **Portable:** Transfer your entire knowledge base between devices (even with others) with minimal cost - your personal AI memory travels with you.

📈 **Scalability:** Handle messy personal data that would crash traditional vector DBs, easily managing your growing personalized data and agent generated memory!

✨ **No Accuracy Loss:** Maintain the same search quality as heavyweight solutions while using 97% less storage.

## Installation

<details>
<summary><strong>📦 Prerequisites: Install uv (if you don't have it)</strong></summary>

Install uv first if you don't have it:

```bash
curl -LsSf https://astral.sh/uv/install.sh | sh
```

📖 [Detailed uv installation methods →](https://docs.astral.sh/uv/getting-started/installation/#installation-methods)

</details>


LEANN provides two installation methods: **pip install** (quick and easy) and **build from source** (recommended for development).



### 🚀 Quick Install (Recommended for most users)

Clone the repository to access all examples and install LEANN from [PyPI](https://pypi.org/project/leann/) to run them immediately:

```bash
git clone git@github.com:yichuan-w/LEANN.git leann
cd leann
uv venv
source .venv/bin/activate
uv pip install leann
```

### 🔧 Build from Source (Recommended for development)

```bash
git clone git@github.com:yichuan-w/LEANN.git leann
cd leann
git submodule update --init --recursive
```

**macOS:**
```bash
brew install llvm libomp boost protobuf zeromq pkgconf
CC=$(brew --prefix llvm)/bin/clang CXX=$(brew --prefix llvm)/bin/clang++ uv sync
```

**Linux:**
```bash
sudo apt-get install libomp-dev libboost-all-dev protobuf-compiler libabsl-dev libmkl-full-dev libaio-dev libzmq3-dev
uv sync
```




## Quick Start

Our declarative API makes RAG as easy as writing a config file.

[![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/yichuan-w/LEANN/blob/main/demo.ipynb) [Try in this ipynb file →](demo.ipynb)

```python
from leann import LeannBuilder, LeannSearcher, LeannChat
from pathlib import Path
INDEX_PATH = str(Path("./").resolve() / "demo.leann")

# Build an index
builder = LeannBuilder(backend_name="hnsw")
builder.add_text("LEANN saves 97% storage compared to traditional vector databases.")
builder.add_text("Tung Tung Tung Sahur called—they need their banana‑crocodile hybrid back")
builder.build_index(INDEX_PATH)

# Search
searcher = LeannSearcher(INDEX_PATH)
results = searcher.search("fantastical AI-generated creatures", top_k=1)

# Chat with your data
chat = LeannChat(INDEX_PATH, llm_config={"type": "hf", "model": "Qwen/Qwen3-0.6B"})
response = chat.ask("How much storage does LEANN save?", top_k=1)
```

## RAG on Everything!

LEANN supports RAG on various data sources including documents (.pdf, .txt, .md), Apple Mail, Google Search History, WeChat, and more.


> **Generation Model Setup**
> LEANN supports multiple LLM providers for text generation (OpenAI API, HuggingFace, Ollama).

<details>
<summary><strong>🔑 OpenAI API Setup (Default)</strong></summary>

Set your OpenAI API key as an environment variable:

```bash
export OPENAI_API_KEY="your-api-key-here"
```

</details>

<details>
<summary><strong>🔧 Ollama Setup (Recommended for full privacy)</strong></summary>

**macOS:**

First, [download Ollama for macOS](https://ollama.com/download/mac).

```bash
# Pull a lightweight model (recommended for consumer hardware)
ollama pull llama3.2:1b
```

**Linux:**

```bash
# Install Ollama
curl -fsSL https://ollama.ai/install.sh | sh

# Start Ollama service manually
ollama serve &

# Pull a lightweight model (recommended for consumer hardware)
ollama pull llama3.2:1b
```

</details>

### 📄 Personal Data Manager: Process Any Documents (.pdf, .txt, .md)!

Ask questions directly about your personal PDFs, documents, and any directory containing your files!

<p align="center">
  <img src="videos/paper_clear.gif" alt="LEANN Document Search Demo" width="600">
</p>

The example below asks a question about summarizing two papers (uses default data in `examples/data`) and this is the easiest example to run here:

```bash
source .venv/bin/activate
python ./examples/main_cli_example.py
```

<details>
<summary><strong>📋 Click to expand: User Configurable Arguments</strong></summary>

```bash
# Use custom index directory
python examples/main_cli_example.py --index-dir "./my_custom_index"

# Use custom data directory
python examples/main_cli_example.py --data-dir "./my_documents"

# Ask a specific question
python examples/main_cli_example.py --query "What are the main findings in these papers?"
```

</details>

### 📧 Your Personal Email Secretary: RAG on Apple Mail!

> **Note:** The examples below currently support macOS only. Windows support coming soon.


<p align="center">
  <img src="videos/mail_clear.gif" alt="LEANN Email Search Demo" width="600">
</p>

**Note:** You need to grant full disk access to your terminal/VS Code in System Preferences → Privacy & Security → Full Disk Access.
```bash
python examples/mail_reader_leann.py --query "What's the food I ordered by DoorDash or Uber Eats mostly?"
```
**780K email chunks → 78MB storage.** Finally, search your email like you search Google.

<details>
<summary><strong>📋 Click to expand: User Configurable Arguments</strong></summary>

```bash
# Use default mail path (works for most macOS setups)
python examples/mail_reader_leann.py

# Run with custom index directory
python examples/mail_reader_leann.py --index-dir "./my_mail_index"

# Process all emails (may take time but indexes everything)
python examples/mail_reader_leann.py --max-emails -1

# Limit number of emails processed (useful for testing)
python examples/mail_reader_leann.py --max-emails 1000

# Run a single query
python examples/mail_reader_leann.py --query "What did my boss say about deadlines?"
```

</details>

<details>
<summary><strong>📋 Click to expand: Example queries you can try</strong></summary>

Once the index is built, you can ask questions like:
- "Find emails from my boss about deadlines"
- "What did John say about the project timeline?"
- "Show me emails about travel expenses"
</details>

### 🔍 Time Machine for the Web: RAG Your Entire Chrome Browser History!

<p align="center">
  <img src="videos/google_clear.gif" alt="LEANN Browser History Search Demo" width="600">
</p>

```bash
python examples/google_history_reader_leann.py --query "Tell me my browser history about machine learning?"
```
**38K browser entries → 6MB storage.** Your browser history becomes your personal search engine.

<details>
<summary><strong>📋 Click to expand: User Configurable Arguments</strong></summary>

```bash
# Use default Chrome profile (auto-finds all profiles)
python examples/google_history_reader_leann.py

# Run with custom index directory
python examples/google_history_reader_leann.py --index-dir "./my_chrome_index"

# Limit number of history entries processed (useful for testing)
python examples/google_history_reader_leann.py --max-entries 500

# Run a single query
python examples/google_history_reader_leann.py --query "What websites did I visit about machine learning?"
```

</details>

<details>
<summary><strong>📋 Click to expand: How to find your Chrome profile</strong></summary>

The default Chrome profile path is configured for a typical macOS setup. If you need to find your specific Chrome profile:

1. Open Terminal
2. Run: `ls ~/Library/Application\ Support/Google/Chrome/`
3. Look for folders like "Default", "Profile 1", "Profile 2", etc.
4. Use the full path as your `--chrome-profile` argument

**Common Chrome profile locations:**
- macOS: `~/Library/Application Support/Google/Chrome/Default`
- Linux: `~/.config/google-chrome/Default`

</details>

<details>
<summary><strong>💬 Click to expand: Example queries you can try</strong></summary>

Once the index is built, you can ask questions like:

- "What websites did I visit about machine learning?"
- "Find my search history about programming"
- "What YouTube videos did I watch recently?"
- "Show me websites I visited about travel planning"

</details>

### 💬 WeChat Detective: Unlock Your Golden Memories!

<p align="center">
  <img src="videos/wechat_clear.gif" alt="LEANN WeChat Search Demo" width="600">
</p>

```bash
python examples/wechat_history_reader_leann.py --query "Show me all group chats about weekend plans"
```
**400K messages → 64MB storage** Search years of chat history in any language.


<details>
<summary><strong>🔧 Click to expand: Installation Requirements</strong></summary>

First, you need to install the WeChat exporter:

```bash
sudo packages/wechat-exporter/wechattweak-cli install
```

**Troubleshooting:**
- **Installation issues**: Check the [WeChatTweak-CLI issues page](https://github.com/sunnyyoung/WeChatTweak-CLI/issues/41)
- **Export errors**: If you encounter the error below, try restarting WeChat
```
Failed to export WeChat data. Please ensure WeChat is running and WeChatTweak is installed.
Failed to find or export WeChat data. Exiting.
```
</details>

<details>
<summary><strong>📋 Click to expand: User Configurable Arguments</strong></summary>

```bash
# Use default settings (recommended for first run)
python examples/wechat_history_reader_leann.py

# Run with custom export directory and wehn we run the first time, LEANN will export all chat history automatically for you
python examples/wechat_history_reader_leann.py --export-dir "./my_wechat_exports"

# Run with custom index directory
python examples/wechat_history_reader_leann.py --index-dir "./my_wechat_index"

# Limit number of chat entries processed (useful for testing)
python examples/wechat_history_reader_leann.py --max-entries 1000

# Run a single query
python examples/wechat_history_reader_leann.py --query "Show me conversations about travel plans"
```

</details>

<details>
<summary><strong>💬 Click to expand: Example queries you can try</strong></summary>

Once the index is built, you can ask questions like:

- "我想买魔术师约翰逊的球衣，给我一些对应聊天记录?" (Chinese: Show me chat records about buying Magic Johnson's jersey)

</details>



## 🖥️ Command Line Interface

LEANN includes a powerful CLI for document processing and search. Perfect for quick document indexing and interactive chat.

```bash
# Build an index from documents
leann build my-docs --docs ./documents

# Search your documents
leann search my-docs "machine learning concepts"

# Interactive chat with your documents
leann ask my-docs --interactive

# List all your indexes
leann list
```

**Key CLI features:**
- Auto-detects document formats (PDF, TXT, MD, DOCX)
- Smart text chunking with overlap
- Multiple LLM providers (Ollama, OpenAI, HuggingFace)
- Organized index storage in `~/.leann/indexes/`
- Support for advanced search parameters

<details>
<summary><strong>📋 Click to expand: Complete CLI Reference</strong></summary>

**Build Command:**
```bash
leann build INDEX_NAME --docs DIRECTORY [OPTIONS]

Options:
  --backend {hnsw,diskann}     Backend to use (default: hnsw)
  --embedding-model MODEL      Embedding model (default: facebook/contriever)
  --graph-degree N            Graph degree (default: 32)
  --complexity N              Build complexity (default: 64)
  --force                     Force rebuild existing index
  --compact                   Use compact storage (default: true)
  --recompute                 Enable recomputation (default: true)
```

**Search Command:**
```bash
leann search INDEX_NAME QUERY [OPTIONS]

Options:
  --top-k N                   Number of results (default: 5)
  --complexity N              Search complexity (default: 64)
  --recompute-embeddings      Use recomputation for highest accuracy
  --pruning-strategy {global,local,proportional}
```

**Ask Command:**
```bash
leann ask INDEX_NAME [OPTIONS]

Options:
  --llm {ollama,openai,hf}    LLM provider (default: ollama)
  --model MODEL               Model name (default: qwen3:8b)
  --interactive              Interactive chat mode
  --top-k N                  Retrieval count (default: 20)
```

</details>

## 🏗️ Architecture & How It Works

<p align="center">
  <img src="assets/arch.png" alt="LEANN Architecture" width="800">
</p>

**The magic:** Most vector DBs store every single embedding (expensive). LEANN stores a pruned graph structure (cheap) and recomputes embeddings only when needed (fast).

**Core techniques:**
- **Graph-based selective recomputation:** Only compute embeddings for nodes in the search path
- **High-degree preserving pruning:** Keep important "hub" nodes while removing redundant connections
- **Dynamic batching:** Efficiently batch embedding computations for GPU utilization
- **Two-level search:** Smart graph traversal that prioritizes promising nodes

**Backends:** DiskANN or HNSW - pick what works for your data size.

## Benchmarks


📊 **[Simple Example: Compare LEANN vs FAISS →](examples/compare_faiss_vs_leann.py)**
### Storage Comparison

| System | DPR (2.1M) | Wiki (60M) | Chat (400K) | Email (780K) | Browser (38K) |
|--------|-------------|------------|-------------|--------------|---------------|
| Traditional vector database (e.g., FAISS) | 3.8 GB      | 201 GB     | 1.8 GB     | 2.4 GB      | 130 MB        |
| LEANN  | 324 MB      | 6 GB       | 64 MB       | 79 MB       | 6.4 MB        |
| Savings| 91%         | 97%        | 97%         | 97%         | 95%           |



## Reproduce Our Results

```bash
uv pip install -e ".[dev]"  # Install dev dependencies
python examples/run_evaluation.py data/indices/dpr/dpr_diskann      # DPR dataset
python examples/run_evaluation.py data/indices/rpj_wiki/rpj_wiki.index  # Wikipedia
```

The evaluation script downloads data automatically on first run. The last three results were tested with partial personal data, and you can reproduce them with your own data!
## 🔬 Paper

If you find Leann useful, please cite:

**[LEANN: A Low-Storage Vector Index](https://arxiv.org/abs/2506.08276)**

```bibtex
@misc{wang2025leannlowstoragevectorindex,
      title={LEANN: A Low-Storage Vector Index},
      author={Yichuan Wang and Shu Liu and Zhifei Li and Yongji Wu and Ziming Mao and Yilong Zhao and Xiao Yan and Zhiying Xu and Yang Zhou and Ion Stoica and Sewon Min and Matei Zaharia and Joseph E. Gonzalez},
      year={2025},
      eprint={2506.08276},
      archivePrefix={arXiv},
      primaryClass={cs.DB},
      url={https://arxiv.org/abs/2506.08276},
}
```

## ✨ [Detailed Features →](docs/features.md)

## 🤝 [CONTRIBUTING →](docs/CONTRIBUTING.md)


## ❓ [FAQ →](docs/faq.md)


## 📈 [Roadmap →](docs/roadmap.md)

## 📄 License

MIT License - see [LICENSE](LICENSE) for details.

## 🙏 Acknowledgments

This work is done at [**Berkeley Sky Computing Lab**](https://sky.cs.berkeley.edu/)
---

<p align="center">
  <strong>⭐ Star us on GitHub if Leann is useful for your research or applications!</strong>
</p>

<p align="center">
  Made with ❤️ by the Leann team
</p>
