Hugging Face Reranker - Mem0

Overview

The Hugging Face reranker provider gives you access to thousands of reranking models available on the Hugging Face Hub. This includes popular models like BAAI’s BGE rerankers and other state-of-the-art cross-encoder models.

Configuration

Basic Setup

from mem0 import Memory

config = {
    "reranker": {
        "provider": "huggingface",
        "config": {
            "model": "BAAI/bge-reranker-base",
            "device": "cpu"
        }
    }
}

m = Memory.from_config(config)

Configuration Parameters

Advanced Configuration

config = {
    "reranker": {
        "provider": "huggingface",
        "config": {
            "model": "BAAI/bge-reranker-large",
            "device": "cuda",
            "batch_size": 16,
            "max_length": 512,
            "trust_remote_code": False,
            "model_kwargs": {
                "torch_dtype": "float16"
            }
        }
    }
}

TypeScript (self-hosted)

The TypeScript OSS SDK (mem0ai/oss) runs this reranker locally with Transformers.js, the same cross-encoder path as sentence_transformer, just a different default model. It executes ONNX weights, so the default is the ONNX mirror Xenova/bge-reranker-base. Point model at any ONNX-exported reranker on the Hub (a raw BAAI/bge-reranker-* PyTorch checkpoint will not load in this runtime).

pnpm add @huggingface/transformers

import { Memory } from "mem0ai/oss";

const memory = new Memory({
  reranker: {
    provider: "huggingface",
    config: {
      // model: "Xenova/bge-reranker-base", // default (ONNX)
      device: "cpu", // "cpu" | "wasm" | "webgpu"
      maxLength: 512, // max tokens per query-document pair
      normalize: true, // sigmoid-normalize logits to [0, 1] (default)
      topK: 5,
    },
  },
});

const results = await memory.search("What are the user's interests?", {
  filters: { userId: "alice" },
  rerank: true,
});

batchSize and showProgressBar are accepted for parity with the Python SDK but are no-ops in the TypeScript runtime. trust_remote_code and model_kwargs are Python-only.

Popular Models

BGE Rerankers (Recommended)

# Base model - good balance of speed and quality
config = {
    "reranker": {
        "provider": "huggingface",
        "config": {
            "model": "BAAI/bge-reranker-base",
            "device": "cuda"
        }
    }
}

# Large model - better quality, slower
config = {
    "reranker": {
        "provider": "huggingface",
        "config": {
            "model": "BAAI/bge-reranker-large",
            "device": "cuda"
        }
    }
}

# v2 models - latest improvements
config = {
    "reranker": {
        "provider": "huggingface",
        "config": {
            "model": "BAAI/bge-reranker-v2-m3",
            "device": "cuda"
        }
    }
}

Multilingual Models

# Multilingual BGE reranker
config = {
    "reranker": {
        "provider": "huggingface",
        "config": {
            "model": "BAAI/bge-reranker-v2-multilingual",
            "device": "cuda"
        }
    }
}

Domain-Specific Models

# For code search
config = {
    "reranker": {
        "provider": "huggingface",
        "config": {
            "model": "microsoft/codebert-base",
            "device": "cuda"
        }
    }
}

# For biomedical content
config = {
    "reranker": {
        "provider": "huggingface",
        "config": {
            "model": "dmis-lab/biobert-base-cased-v1.1",
            "device": "cuda"
        }
    }
}
}

Usage Examples

Basic Usage

from mem0 import Memory

m = Memory.from_config(config)

# Add some memories
m.add("I love hiking in the mountains", user_id="alice")
m.add("Pizza is my favorite food", user_id="alice")
m.add("I enjoy reading science fiction books", user_id="alice")

# Search with reranking
results = m.search(
    "What outdoor activities do I enjoy?",
    user_id="alice",
    rerank=True
)

for result in results["results"]:
    print(f"Memory: {result['memory']}")
    print(f"Score: {result['score']:.3f}")

Batch Processing

# Process multiple queries efficiently
queries = [ \
    "What are my hobbies?", \
    "What food do I like?", \
    "What books interest me?" \
]

results = []
for query in queries:
    result = m.search(query, filters={"user_id": "alice"}, rerank=True)
    results.append(result)

Performance Optimization

GPU Acceleration

# Use GPU for better performance
config = {
    "reranker": {
        "provider": "huggingface",
        "config": {
            "model": "BAAI/bge-reranker-base",
            "device": "cuda",
            "batch_size": 64,  # Increase batch size for GPU
        }
    }
}

Memory Optimization

# For limited memory environments
config = {
    "reranker": {
        "provider": "huggingface",
        "config": {
            "model": "BAAI/bge-reranker-base",
            "device": "cpu",
            "batch_size": 8,   # Smaller batch size
            "max_length": 256, # Shorter sequences
            "model_kwargs": {
                "torch_dtype": "float16"  # Half precision
            }
        }
    }
}

Model Comparison

Error Handling

try:
    results = m.search(
        "test query",
        user_id="alice",
        rerank=True
    )
except Exception as e:
    print(f"Reranking failed: {e}")
    # Fall back to vector search only
    results = m.search(
        "test query",
        user_id="alice",
        rerank=False
    )

Custom Models

Using Private Models

# Use a private model from Hugging Face
config = {
    "reranker": {
        "provider": "huggingface",
        "config": {
            "model": "your-org/custom-reranker",
            "device": "cuda",
            "use_auth_token": "your-hf-token"
        }
    }
}

Local Model Path

# Use a locally downloaded model
config = {
    "reranker": {
        "provider": "huggingface",
        "config": {
            "model": "/path/to/local/model",
            "device": "cuda"
        }
    }
}

Best Practices

1. Choose the Right Model: Balance quality vs speed based on your needs
2. Use GPU: Significantly faster than CPU for larger models
3. Optimize Batch Size: Tune based on your hardware capabilities
4. Monitor Memory: Watch GPU/CPU memory usage with large models
5. Cache Models: Download once and reuse to avoid repeated downloads

Troubleshooting

Common Issues

Out of Memory Error

# Reduce batch size and sequence length
config = {
    "reranker": {
        "provider": "huggingface",
        "config": {
            "model": "BAAI/bge-reranker-base",
            "batch_size": 4,
            "max_length": 256
        }
    }
}

Model Download Issues

# Set cache directory
import os
os.environ["TRANSFORMERS_CACHE"] = "/path/to/cache"

# Or use offline mode
config = {
    "reranker": {
        "provider": "huggingface",
        "config": {
            "model": "BAAI/bge-reranker-base",
            "local_files_only": True
        }
    }
}

CUDA Not Available

import torch

config = {
    "reranker": {
        "provider": "huggingface",
        "config": {
            "model": "BAAI/bge-reranker-base",
            "device": "cuda" if torch.cuda.is_available() else "cpu"
        }
    }
}

Next Steps

Reranker Overview \ \ Learn about reranking concepts

Configuration Guide \ \ Detailed configuration options