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*   [](/v0.1/)
*   [Components](/v0.1/docs/integrations/components/)
*   [Chat Memory](/v0.1/docs/integrations/chat_memory/)
*   MongoDB Chat Memory

MongoDB Chat Memory
===================

Compatibility

Only available on Node.js.

You can still create API routes that use MongoDB with Next.js by setting the `runtime` variable to `nodejs` like so:

    export const runtime = "nodejs";

You can read more about Edge runtimes in the Next.js documentation [here](https://nextjs.org/docs/app/building-your-application/rendering/edge-and-nodejs-runtimes).

For longer-term persistence across chat sessions, you can swap out the default in-memory `chatHistory` that backs chat memory classes like `BufferMemory` for a MongoDB instance.

Setup[​](#setup "Direct link to Setup")
---------------------------------------

You need to install Node MongoDB SDK in your project:

*   npm
*   Yarn
*   pnpm

    npm install -S mongodb

    yarn add mongodb

    pnpm add mongodb

tip

See [this section for general instructions on installing integration packages](/v0.1/docs/get_started/installation/#installing-integration-packages).

*   npm
*   Yarn
*   pnpm

    npm install @langchain/openai @langchain/community

    yarn add @langchain/openai @langchain/community

    pnpm add @langchain/openai @langchain/community

You will also need a MongoDB instance to connect to.

Usage[​](#usage "Direct link to Usage")
---------------------------------------

Each chat history session stored in MongoDB must have a unique session id.

    import { MongoClient, ObjectId } from "mongodb";import { BufferMemory } from "langchain/memory";import { ChatOpenAI } from "@langchain/openai";import { ConversationChain } from "langchain/chains";import { MongoDBChatMessageHistory } from "@langchain/mongodb";const client = new MongoClient(process.env.MONGODB_ATLAS_URI || "", {  driverInfo: { name: "langchainjs" },});await client.connect();const collection = client.db("langchain").collection("memory");// generate a new sessionId stringconst sessionId = new ObjectId().toString();const memory = new BufferMemory({  chatHistory: new MongoDBChatMessageHistory({    collection,    sessionId,  }),});const model = new ChatOpenAI({  model: "gpt-3.5-turbo",  temperature: 0,});const chain = new ConversationChain({ llm: model, memory });const res1 = await chain.invoke({ input: "Hi! I'm Jim." });console.log({ res1 });/*  {    res1: {      text: "Hello Jim! It's nice to meet you. My name is AI. How may I assist you today?"    }  }  */const res2 = await chain.invoke({ input: "What did I just say my name was?" });console.log({ res2 });/*  {    res1: {      text: "You said your name was Jim."    }  }  */// See the chat history in the MongoDbconsole.log(await memory.chatHistory.getMessages());// clear chat historyawait memory.chatHistory.clear();

#### API Reference:

*   [BufferMemory](https://api.js.langchain.com/classes/langchain_memory.BufferMemory.html) from `langchain/memory`
*   [ChatOpenAI](https://api.js.langchain.com/classes/langchain_openai.ChatOpenAI.html) from `@langchain/openai`
*   [ConversationChain](https://api.js.langchain.com/classes/langchain_chains.ConversationChain.html) from `langchain/chains`
*   [MongoDBChatMessageHistory](https://api.js.langchain.com/classes/langchain_mongodb.MongoDBChatMessageHistory.html) from `@langchain/mongodb`

* * *

#### Help us out by providing feedback on this documentation page:

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