Voyage AI Reranker

Voyage AI's reranking models are high-quality cross-encoder rerankers that significantly improve retrieval precision. Built by the same team behind the top-ranked Voyage embeddings, they are optimized for RAG applications.

Setup

[dependencies]
synaptic = { version = "0.4", features = ["voyage"] }

Sign up at voyageai.com and create an API key.

Available Models

Usage

use synaptic::voyage::reranker::{VoyageReranker, VoyageRerankerModel};
use synaptic::core::Document;

let reranker = VoyageReranker::new("pa-your-api-key")
    .with_model(VoyageRerankerModel::Rerank2);

let docs = vec![
    Document::new("doc1", "Paris is the capital of France."),
    Document::new("doc2", "The Eiffel Tower is in Paris."),
    Document::new("doc3", "Berlin is the capital of Germany."),
    Document::new("doc4", "France is a country in Western Europe."),
];

let results = reranker
    .rerank("What is the capital of France?", docs, 2)
    .await?;

for (doc, score) in &results {
    println!("{:.4}: {}", score, doc.content);
}
// Output (example):
// 0.9234: Paris is the capital of France.
// 0.6821: France is a country in Western Europe.

RAG Pipeline Integration

use synaptic::voyage::reranker::VoyageReranker;
use synaptic::voyage::VoyageEmbeddings;
use synaptic::vectorstores::InMemoryVectorStore;

// Retrieve 20 candidates with fast vector search
let candidates = vector_store
    .similarity_search("capital of France", 20, &embeddings)
    .await?;

// Rerank to top 5 with Voyage cross-encoder
let reranker = VoyageReranker::new("pa-your-api-key");
let top5 = reranker
    .rerank("capital of France", candidates, 5)
    .await?;

// Use top5 as context for the LLM

Custom Endpoint

Point to a custom or self-hosted deployment:

let reranker = VoyageReranker::new("pa-key")
    .with_base_url("https://custom.voyageai.com/v1");

Error Handling

use synaptic::core::SynapticError;

match reranker.rerank(query, docs, k).await {
    Ok(results) => {
        for (doc, score) in results {
            println!("{:.4}: {}", score, doc.content);
        }
    }
    Err(SynapticError::Retriever(msg)) => eprintln!("Rerank error: {}", msg),
    Err(e) => return Err(e.into()),
}

Configuration Reference