Integrations

LangChain

Trace your LangChain applications by configuring a LangChain callback handler.

Installation

Install the LangChain integration and Braintrust SDK:

pnpm add braintrust @braintrust/langchain-js @langchain/core @langchain/openai

Usage

trace-langchain.ts
import { BraintrustCallbackHandler } from "@braintrust/langchain-js";
import { ChatOpenAI } from "@langchain/openai";
import { initLogger } from "braintrust";
 
initLogger({
  projectName: "My Project",
  apiKey: process.env.BRAINTRUST_API_KEY,
});
 
const handler = new BraintrustCallbackHandler();
 
async function main() {
  const model = new ChatOpenAI({ modelName: "gpt-4o-mini" });
 
  await model.invoke("What is the capital of France?", {
    callbacks: [handler],
  });
}
 
main();

Learn more about LangChain callbacks in their documentation.

On this page

LangChain - Docs - Braintrust