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

# LangChain with Upstash Vector

You can use LangChain with Upstash Vector to perform semantic search and manage vector embeddings. LangChain is a powerful framework that integrates with vector databases, including Upstash Vector, making it easy to build intelligent applications.

First, we need to create a Vector Index in the [Upstash Console](https://console.upstash.com). To learn more about index creation, you can check out [this page](https://docs.upstash.com/vector/overall/getstarted).

## Install

```bash theme={"system"}
pip install upstash-vector langchain langchain-community python-dotenv
```

## Usage

```python theme={"system"}
from dotenv import load_dotenv
from langchain_community.vectorstores.upstash import UpstashVectorStore
from langchain.schema import Document

# Load environment variables
load_dotenv()

# Create a vector store instance
store = UpstashVectorStore(
    embedding=True,  # Embedding option enabled
)

# Sample documents to upload
documents = [
    Document(page_content="Upstash Vector is a scalable vector database."),
    Document(page_content="LangChain is a framework for building intelligent apps."),
    Document(page_content="Semantic search enables advanced query matching."),
]

# Add documents to the Upstash Vector index
store.add_documents(documents)

# Perform a similarity search
query = "What is LangChain?"
results = store.similarity_search(query, k=3)

print("Similarity Search Results:")
for res in results:
    print(res.page_content)
```

### Query Results

```plaintext theme={"system"}
Similarity Search Results:
LangChain is a framework for building intelligent apps.
Semantic search enables advanced query matching.
Upstash Vector is a scalable vector database.
```

## Features

**Semantic Search**: Retrieve the most contextually relevant results using embeddings and vector similarity.

**Namespace Support**: Separate documents into different namespaces for better organization.

**Metada Filtering**: Metadata can be used to filter the results of a query.

## Notes

* Upstash Vector supports custom embeddings; you can specify an embedding model when initializing `UpstashVectorStore`.
* Use `.env` files to manage your Upstash credentials for secure and reusable configuration.

To learn more, visit the [LangChain documentation](https://python.langchain.com/docs/integrations/vectorstores/upstash/).