# LangChain: Streaming Structured Output in JavaScript

DevFeed: [LangChain: Streaming Structured Output in JavaScript](<https://devfeed.tech/articles/langchain-streaming-structured-output-in-javascript-18943.md>)

Original publisher: [Read original article](<https://www.robinwieruch.de/langchain-javascript-stream-structured/>)

Author: Robin Wieruch

Published: 2025-02-10T06:53:46Z

Content type: tutorial

Language: en

Sources: [Robin Wieruch](<https://devfeed.tech/sources/robin-wieruch.md>)

Topics: [LangChain](<https://devfeed.tech/topics/langchain.md>), [JavaScript](<https://devfeed.tech/topics/javascript.md>), [Streaming](<https://devfeed.tech/topics/streaming.md>), [Structured-data](<https://devfeed.tech/topics/structured-data.md>), [Next.js](<https://devfeed.tech/topics/next-js.md>), [API](<https://devfeed.tech/topics/api.md>), [React](<https://devfeed.tech/topics/react.md>), [Back end](<https://devfeed.tech/topics/backend.md>), [Front end](<https://devfeed.tech/topics/frontend.md>)

Tags: [api](<https://devfeed.tech/tags/api.md>), [backend](<https://devfeed.tech/tags/backend.md>), [fetch](<https://devfeed.tech/tags/fetch.md>), [frontend](<https://devfeed.tech/tags/frontend.md>), [github](<https://devfeed.tech/tags/github.md>), [javascript](<https://devfeed.tech/tags/javascript.md>), [langchain](<https://devfeed.tech/tags/langchain.md>), [langchain-javascript-stream-structured-output](<https://devfeed.tech/tags/langchain-javascript-stream-structured-output.md>), [next-js](<https://devfeed.tech/tags/next-js.md>), [react](<https://devfeed.tech/tags/react.md>), [server-sent-events](<https://devfeed.tech/tags/server-sent-events.md>), [streaming](<https://devfeed.tech/tags/streaming.md>), [structured-output](<https://devfeed.tech/tags/structured-output.md>)

## AI overview

This tutorial demonstrates how to stream structured output in JavaScript with LangChain, using Next.js and React for the frontend and backend. It explains using Server-Sent Events and the native fetch API with @microsoft/fetch-event-source while building a chatbot application that uses the OpenAI API.

## Source excerpt

How to: Streaming Structured Output in JavaScript with LangChain. A step by step example on how to stream structured data in JavaScript with LangChain ...