embeddingsHand-written lesson

Voyage

voyage-4

voyageai/voyage-4

A general-purpose, multilingual embedding model from Voyage (MongoDB) for retrieval and search. Supports 2048, 1024, 512, and 256 dimensions with several quantization options.

RoleThe search index

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In / M

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Out / M

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Context

AA intelligence index
Not on listing
Inputs
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Outputs
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Tools
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Structured output
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Reasoning
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Weights
Not verified
Listed
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Not in the current catalog snapshot ↗

01 · What it's good at

Use it for this.

Three jobs this model is built for, and the ones to give to something else.

01

Semantic search and RAG indexes

02

Multilingual retrieval

03

Trading vector size for storage cost (256 to 2048 dims)

Skip it for

  • Writing the answer. Pair it with a reranker and a chat model
  • Code search, where voyage-code-4 is the specialist

02 · Example tasks

What you'd actually send it.

Real inputs, not a benchmark. Paste one into the snippet below to try it.

You send

Embed every help-center article, chunked by heading, and store vectors with the article URL.

Why this model

The first step of any RAG pipeline.

03 · Your stack

Where it sits: Retrieve.

Index time: chunk documents and embed them into a vector store (pgvector, Pinecone, Qdrant, or in memory to start). Query time: embed the question with the same model, take the top 20 to 50 hits, and pass them to a reranker.

04 · Wire it up

One request. Paste and run.

Uses OpenRouter, so one key works for every model on this site. Set OPENROUTER_API_KEY and swap the prompt for one of the tasks above.

const res = await fetch("https://openrouter.ai/api/v1/embeddings", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.OPENROUTER_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "model": "voyageai/voyage-4",
    "input": [
      "How do I reset my password?",
      "Billing runs on the first of each month.",
      "SSO is available on the Business plan."
    ]
  }),
});
const { data } = await res.json();
// One vector per input, in order. Store each with its source text.
const vectors = data.map((item: { embedding: number[] }) => item.embedding);
console.log(vectors.length, vectors[0].length);

05 · Watch out for

Gotchas.

  • Embed queries and documents with the same model. Vectors from different models do not mix.

  • Chunk long documents even though inputs can be long. Smaller chunks usually retrieve better.

Sources

Lessons are written from each model's listing and the linked docs. We don't publish our own benchmark numbers; the index above is Artificial Analysis, as shown on OpenRouter.

Keep learning

Same board, other models.