fastembed/README.md

⚡️ What is FastEmbed?

FastEmbed is an easy to use -- lightweight, fast, Python library built for retrieval embedding generation.

The default embedding supports "query" and "passage" prefixes for the input text. The default model is Flag Embedding, which is top of the MTEB leaderboard.

1. Light

   • Quantized model weights
   • ONNX Runtime for inference
   • No hidden dependencies on PyTorch or TensorFlow via Huggingface Transformers

2. Accuracy/Recall

   • Better than OpenAI Ada-002
   • Default is Flag Embedding, which is top of the MTEB leaderboard

3. Fast

   • About 2x faster than Huggingface (PyTorch) transformers on single queries
   • Lot faster for batches!
   • ONNX Runtime allows you to use dedicated runtimes for even higher throughput and lower latency

🚀 Installation

To install the FastEmbed library, pip works:

pip install fastembed

📖 Usage

from fastembed.embedding import FlagEmbedding as Embedding

documents: List[str] = [
    "passage: Hello, World!",
    "query: Hello, World!", # these are two different embedding
    "passage: This is an example passage.",
    # You can leave out the prefix but it's recommended
    "fastembed is supported by and maintained by Qdrant." 
]
embedding_model = Embedding(model_name="BAAI/bge-base-en", max_length=512) 
embeddings: List[np.ndarray] = list(embedding_model.embed(documents))

🚒 Under the hood

Why fast?

It's important we justify the "fast" in FastEmbed. FastEmbed is fast because:

1. Quantized model weights
2. ONNX Runtime which allows for inference on CPU, GPU, and other dedicated runtimes

Why light?

1. No hidden dependencies on PyTorch or TensorFlow via Huggingface Transformers

Why accurate?

1. Better than OpenAI Ada-002
2. Top of the Embedding leaderboards e.g. MTEB