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LangChain.js for Node & TypeScript

14 posts on langchain.js for node & typescript — part of framework tutorials on the n4n AI blog.

14 postsFramework tutorialsAll posts
Framework tutorialsDefinition

TypeScript types for LangChain.js runnables explained

A practical guide to LangChain.js runnable types in TypeScript — what they are, how input/output generics work, and how to compose typed chains without fighting the compiler.

4 min read
Framework tutorialsHow-to

Error handling in LangChain.js with retry and fallback

A practical guide to implementing robust error handling, retry logic, and model fallback chains in LangChain.js for production Node.js and TypeScript applications.

4 min read
Framework tutorialsHow-to

Building a Discord bot with LangChain.js

Build a production-ready Discord bot using LangChain.js with conversation memory, tool calling, and proper error handling.

3 min read
Framework tutorialsComparison

LangChain.js vs LangChain Python: key differences

A practitioner's head-to-head comparison of LangChain.js and LangChain Python across capabilities, ergonomics, ecosystem, and production trade-offs.

6 min read
Framework tutorialsHow-to

LangChain.js streaming responses in an Express API

Build a production-ready Express API with LangChain.js streaming responses, including error handling, token usage tracking, and client-side consumption patterns.

4 min read
Framework tutorialsTutorial

LangChain.js RAG tutorial with Chroma and Node

Build a production-ready RAG pipeline with LangChain.js, Chroma, and Node.js — complete with document loading, embedding, retrieval, and streaming answers.

4 min read
Framework tutorialsGuide

LangChain.js memory management for Node chat apps

Practical guide to LangChain.js memory management in Node chat apps — buffer, summary, and vector stores with code patterns and tradeoffs.

5 min read
Framework tutorialsHow-to

LangChain.js LCEL chains in TypeScript

Build production-ready LCEL chains in TypeScript with streaming, branching, and error handling — runnable code at every step.

4 min read
Framework tutorialsHow-to

Deploying a LangChain.js app to Vercel

A step-by-step guide to deploying a LangChain.js application to Vercel with serverless functions, environment configuration, and streaming responses.

4 min read
Framework tutorialsHow-to

LangChain.js tool calling with GPT-4o via n4n.ai

Hands-on tutorial for LangChain.js tool calling with GPT-4o via n4n.ai: wire OpenAI-compatible models to LangChain tools in Node with working TypeScript code.

3 min read
Framework tutorialsTutorial

LangChain.js quickstart: your first chat chain in Node

A hands-on langchain.js quickstart node chat chain tutorial: build a runnable Node.js chat chain with LangChain.js, from setup to streaming responses.

3 min read
Framework tutorialsGuide

Getting started with LangChain.js and TypeScript

A practical, opinionated guide to langchain.js typescript getting started: project setup, first chains, streaming, pitfalls, and provider fallback.

4 min read
Framework tutorialsHow-to

Connect LangChain.js to n4n.ai with the OpenAI package

Step-by-step guide to connecting LangChain.js to n4n.ai using the OpenAI package, with runnable Node.js code for chat, streaming, and model routing.

3 min read
Framework tutorialsHow-to

Build a Next.js chatbot with LangChain.js

Step-by-step guide to building a langchain.js nextjs chatbot with streaming responses, tool calling, and a production-ready API route in TypeScript.

3 min read

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