> ## Documentation Index
> Fetch the complete documentation index at: https://docs.langchain.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Nebius integration

> Integrate with the Nebius embedding model using LangChain Python.

[Nebius Token Factory](https://tokenfactory.nebius.com/) provides API access to high-quality embedding models through a unified interface. The Nebius embedding models convert text into numerical vectors that capture semantic meaning, making them useful for various applications like semantic search, clustering, and recommendations.

## Overview

The `NebiusEmbeddings` class provides access to Nebius Token Factory's embedding models through LangChain. These embeddings can be used for semantic search, document similarity, and other NLP tasks requiring vector representations of text.

### Integration details

* **Provider**: Nebius Token Factory
* **Model Type**: Text embedding models
* **Primary Use Case**: Generate vector representations of text for semantic similarity and retrieval
* **Currently Highlighted Model**: `Qwen/Qwen3-Embedding-8B`
* **Embedding Dimensions**: 4,096 (for `Qwen/Qwen3-Embedding-8B`)

## Setup

### Installation

The Nebius integration can be installed via pip:

```python theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
pip install -U langchain-nebius
```

### Credentials

Nebius requires an API key that can be passed as an initialization parameter `api_key` or set as the environment variable `NEBIUS_API_KEY`. You can obtain an API key by creating an account on [Nebius Token Factory](https://tokenfactory.nebius.com/).

```python theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
import getpass
import os

# Make sure you've set your API key as an environment variable
if "NEBIUS_API_KEY" not in os.environ:
    os.environ["NEBIUS_API_KEY"] = getpass.getpass("Enter your Nebius API key: ")
```

## Instantiation

The `NebiusEmbeddings` class can be instantiated with optional parameters for the API key and model name:

```python theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
from langchain_nebius import NebiusEmbeddings

# Initialize the embeddings model
embeddings = NebiusEmbeddings(
    # api_key="YOUR_API_KEY",  # You can pass the API key directly
    model="Qwen/Qwen3-Embedding-8B"  # The default embedding model
)
```

### Available models

The list of supported models is available at [Nebius Token Factory Models Page](https://tokenfactory.nebius.com/models?modality=embedding)

## Indexing and retrieval

Embedding models are often used in retrieval-augmented generation (RAG) flows, both for indexing data and later retrieving it. The following example demonstrates how to use `NebiusEmbeddings` with a vector store for document retrieval.

<Warning>
  The `langchain-community` package is no longer maintained. Examples that import from `langchain_community` may be outdated or broken. Use with caution.
</Warning>

```python theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
from langchain_community.vectorstores import FAISS
from langchain_core.documents import Document

# Prepare documents
docs = [
    Document(
        page_content="Machine learning algorithms build mathematical models based on sample data"
    ),
    Document(page_content="Deep learning uses neural networks with many layers"),
    Document(page_content="Climate change is a major global environmental challenge"),
    Document(
        page_content="Neural networks are inspired by the human brain's structure"
    ),
]

# Create vector store
vector_store = FAISS.from_documents(docs, embeddings)

# Perform similarity search
query = "How does the brain influence AI?"
results = vector_store.similarity_search(query, k=2)

print("Search results for query:", query)
for i, doc in enumerate(results):
    print(f"Result {i + 1}: {doc.page_content}")
```

```text theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
Search results for query: How does the brain influence AI?
Result 1: Neural networks are inspired by the human brain's structure
Result 2: Deep learning uses neural networks with many layers
```

### Using with InMemoryVectorStore

You can also use the `InMemoryVectorStore` for lightweight applications:

```python theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
from langchain_core.vectorstores import InMemoryVectorStore

# Create a sample text
text = "LangChain is a framework for developing applications powered by language models"

# Create a vector store
vectorstore = InMemoryVectorStore.from_texts(
    [text],
    embedding=embeddings,
)

# Use as a retriever
retriever = vectorstore.as_retriever()

# Retrieve similar documents
docs = retriever.invoke("What is LangChain?")
print(f"Retrieved document: {docs[0].page_content}")
```

```text theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
Retrieved document: LangChain is a framework for developing applications powered by language models
```

## Direct usage

You can directly use the `NebiusEmbeddings` class to generate embeddings for text without using a vector store.

### Embedding a single text

You can use the `embed_query` method to embed a single piece of text:

```python theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
query = "What is machine learning?"
query_embedding = embeddings.embed_query(query)

# Check the embedding dimension
print(f"Embedding dimension: {len(query_embedding)}")
print(f"First few values: {query_embedding[:5]}")
```

```text theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
Embedding dimension: 4096
First few values: [0.007419586181640625, 0.002246856689453125, 0.00193023681640625, -0.0066070556640625, -0.0179901123046875]
```

### Embedding multiple texts

You can embed multiple texts at once using the `embed_documents` method:

```python theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
documents = [
    "Machine learning is a branch of artificial intelligence",
    "Deep learning is a subfield of machine learning",
    "Natural language processing deals with interactions between computers and human language",
]

document_embeddings = embeddings.embed_documents(documents)

# Check the results
print(f"Number of document embeddings: {len(document_embeddings)}")
print(f"Each embedding has {len(document_embeddings[0])} dimensions")
```

```text theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
Number of document embeddings: 3
Each embedding has 4096 dimensions
```

### Async support

NebiusEmbeddings supports async operations:

```python theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
import asyncio


async def generate_embeddings_async():
    # Embed a single query
    query_result = await embeddings.aembed_query("What is the capital of France?")
    print(f"Async query embedding dimension: {len(query_result)}")

    # Embed multiple documents
    docs = [
        "Paris is the capital of France",
        "Berlin is the capital of Germany",
        "Rome is the capital of Italy",
    ]
    docs_result = await embeddings.aembed_documents(docs)
    print(f"Async document embeddings count: {len(docs_result)}")


await generate_embeddings_async()
```

```text theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
Async query embedding dimension: 4096
Async document embeddings count: 3
```

### Document similarity example

```python theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
import numpy as np
from scipy.spatial.distance import cosine

# Create some documents
documents = [
    "Machine learning algorithms build mathematical models based on sample data",
    "Deep learning uses neural networks with many layers",
    "Climate change is a major global environmental challenge",
    "Neural networks are inspired by the human brain's structure",
]

# Embed the documents
embeddings_list = embeddings.embed_documents(documents)


# Function to calculate similarity
def calculate_similarity(embedding1, embedding2):
    return 1 - cosine(embedding1, embedding2)


# Print similarity matrix
print("Document Similarity Matrix:")
for i, emb_i in enumerate(embeddings_list):
    similarities = []
    for j, emb_j in enumerate(embeddings_list):
        similarity = calculate_similarity(emb_i, emb_j)
        similarities.append(f"{similarity:.4f}")
    print(f"Document {i + 1}: {similarities}")
```

```text theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
Document Similarity Matrix:
Document 1: ['1.0000', '0.8282', '0.5811', '0.7985']
Document 2: ['0.8282', '1.0000', '0.5897', '0.8315']
Document 3: ['0.5811', '0.5897', '1.0000', '0.5918']
Document 4: ['0.7985', '0.8315', '0.5918', '1.0000']
```

***

## API reference

For more details about the Nebius Token Factory API, visit the [Nebius Token Factory Documentation](https://docs.tokenfactory.nebius.com/quickstart).

***

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