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

# ChatUpstage

This notebook covers how to get started with Upstage chat models.

## Installation

Install `langchain-upstage` package.

```bash theme={null}
pip install -U langchain-upstage
```

## Environment Setup

Make sure to set the following environment variables:

* `UPSTAGE_API_KEY`: Your Upstage API key from [Upstage console](https://console.upstage.ai/).

## Usage

```python theme={null}
import os

os.environ["UPSTAGE_API_KEY"] = "YOUR_API_KEY"
```

```python theme={null}
from langchain_core.prompts import ChatPromptTemplate
from langchain_upstage import ChatUpstage

chat = ChatUpstage()
```

```python theme={null}
# using chat invoke
chat.invoke("Hello, how are you?")
```

```python theme={null}
# using chat stream
for m in chat.stream("Hello, how are you?"):
    print(m)
```

## Chaining

```python theme={null}
# using chain
prompt = ChatPromptTemplate.from_messages(
    [
        ("system", "You are a helpful assistant that translates English to French."),
        ("human", "Translate this sentence from English to French. {english_text}."),
    ]
)
chain = prompt | chat

chain.invoke({"english_text": "Hello, how are you?"})
```