# StreamlitChatMessageHistory

> **Class** in `langchain_community`

📖 [View in docs](https://reference.langchain.com/python/langchain-community/chat_message_histories/streamlit/StreamlitChatMessageHistory)

Chat message history that stores messages in Streamlit session state.

## Signature

```python
StreamlitChatMessageHistory(
    self,
    key: str = 'langchain_messages',
)
```

## Parameters

| Name | Type | Required | Description |
|------|------|----------|-------------|
| `key` | `str` | No | The key to use in Streamlit session state for storing messages. (default: `'langchain_messages'`) |

## Extends

- `BaseChatMessageHistory`

## Constructors

```python
__init__(
    self,
    key: str = 'langchain_messages',
)
```

| Name | Type |
|------|------|
| `key` | `str` |


## Properties

- `messages`

## Methods

- [`add_message()`](https://reference.langchain.com/python/langchain-community/chat_message_histories/streamlit/StreamlitChatMessageHistory/add_message)
- [`clear()`](https://reference.langchain.com/python/langchain-community/chat_message_histories/streamlit/StreamlitChatMessageHistory/clear)

---

[View source on GitHub](https://github.com/langchain-ai/langchain-community/blob/a6a6079511ac8a5c1293337f88096b8641562e77/libs/community/langchain_community/chat_message_histories/streamlit.py#L7)