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Cohere provides enterprise-grade reranking models with excellent multilingual support and production-ready performance.

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Models

Cohere offers several reranking models:
  • rerank-v3.5 (default): Latest reranker, multilingual, best performance
  • rerank-english-v3.0: Previous generation, English only
  • rerank-multilingual-v3.0: Previous generation, multilingual

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Installation

pip install cohere

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Configuration

Python
from mem0 import Memory

config = {
    "vector_store": {
        "provider": "chroma",
        "config": {
            "collection_name": "my_memories",
            "path": "./chroma_db"
        }
    },
    "llm": {
        "provider": "openai",
        "config": {
            "model": "gpt-5-mini"
        }
    },
    "reranker": {
        "provider": "cohere",
        "config": {
            "model": "rerank-v3.5",
            "api_key": "your-cohere-api-key",  # or set COHERE_API_KEY
            "top_k": 5,
            "return_documents": False,
            "max_chunks_per_doc": None
        }
    }
}

memory = Memory.from_config(config)

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TypeScript (self-hosted)

The TypeScript OSS SDK (mem0ai/oss) ships the Cohere reranker. Config keys are camelCase, it defaults to the rerank-v3.5 model, and you opt in per search with rerank: true. 
pnpm add cohere-ai

import { Memory } from "mem0ai/oss";

const memory = new Memory({
  reranker: {
    provider: "cohere",
    config: {
      apiKey: process.env.COHERE_API_KEY, // or set COHERE_API_KEY
      // model: "rerank-v3.5",     // default
      topK: 5,
    },
  },
});

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

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Environment Variables

Set your API key as an environment variable: 
export COHERE_API_KEY="your-api-key"

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Usage Example

Python
import os
from mem0 import Memory

# Set API key
os.environ["COHERE_API_KEY"] = "your-api-key"

# Initialize memory with Cohere reranker
config = {
    "vector_store": {"provider": "chroma"},
    "llm": {"provider": "openai", "config": {"model": "gpt-4o-mini"}},
    "rerank": {
        "provider": "cohere",
        "config": {
            "model": "rerank-v3.5",
            "top_k": 3
        }
    }
}

memory = Memory.from_config(config)

# Add memories
messages = [
    {"role": "user", "content": "I work as a data scientist at Microsoft"},
    {"role": "user", "content": "I specialize in machine learning and NLP"},
    {"role": "user", "content": "I enjoy playing tennis on weekends"}
]

memory.add(messages, user_id="bob")

# Search with reranking
results = memory.search("What is the user's profession?", filters={"user_id": "bob"})

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

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Multilingual Support

For multilingual applications, use the multilingual model:
Python
config = {
    "rerank": {
        "provider": "cohere",
        "config": {
            "model": "rerank-multilingual-v3.0",
            "top_k": 5
        }
    }
}

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Configuration Parameters

ParameterDescriptionTypeDefault
modelCohere rerank model to usestr"rerank-v3.5"
api_keyCohere API keystrNone
top_kMaximum documents to returnintNone
return_documentsWhether to return document textsboolFalse
max_chunks_per_docMaximum chunks per documentintNone

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Features

  • High Quality: Enterprise-grade relevance scoring
  • Multilingual: Support for 100+ languages
  • Scalable: Production-ready with high throughput
  • Reliable: SLA-backed service with 99.9% uptime

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Best Practices

  1. Model Selection: rerank-v3.5 handles English and multilingual workloads; pin an older v3.0 model only if you need to reproduce prior results
  2. Batch Processing: Process multiple queries efficiently
  3. Error Handling: Implement retry logic for production systems
  4. Monitoring: Track reranking performance and costs