What is LangChain?
Quick answer
LangChain is an open-source developer framework for building apps on top of large language models. It supplies ready parts, such as chains of prompts, agents that use tools, memory and connectors to vector databases, so developers don't build them from scratch. It is available for Python and JavaScript.
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Updated · By Robert Breen
Why it matters for a small business
LangChain launched in late 2022 and quickly became one of the most used toolkits for AI apps. Its parts have names you meet in no-code tools too: a "chain" runs a prompt through a model in fixed steps, an "agent" lets the model decide which tool to call, and "memory" keeps past messages in a conversation.
You may never write LangChain code, but you may already use it. n8n's docs explain that its AI features are built on LangChain, and the AI nodes ship in a package called @n8n/n8n-nodes-langchain. That is why n8n has nodes named Basic LLM Chain and AI Agent, and why models, memory and tools plug into an agent as separate pieces.
In a real lesson: Answer Staff Questions from Your Own Docs using n8n + Pinecone
In Answer Staff Questions from Your Own Docs, you build the Cedar Ridge Partners handbook chatbot from LangChain-style parts in n8n: an AI Agent, an OpenAI Chat Model, Simple Memory, and a Pinecone Vector Store tool in Retrieve Documents (As Tool for AI Agent) mode, with Embeddings OpenAI attached to it.
The lesson never mentions LangChain by name. You just click the + under Chat Model, Memory and Tool. Each slot is one of LangChain's building blocks, and n8n wires them together for you. In Gmail AI Triage you meet another: the Basic LLM Chain that writes the draft reply.
Try this lesson free or read the step-by-step guide.
Common confusions
LangChain vs n8n
LangChain is a code library for developers. n8n is a visual workflow tool that uses LangChain inside its AI nodes, so you get the parts without writing code.
LangChain vs LangGraph
LangGraph comes from the same company and is aimed at agents with many steps and branches. LangChain is the broader toolkit of parts.
Tips
- When n8n's docs or forum mention LangChain, read it as "the AI nodes": the advice usually applies to you.
- Learn the four parts, model, memory, tools and chain, and most AI builders will look familiar.
- Only reach for LangChain code when a no-code AI node truly can't do the job.
Related terms
More AI agents terms
Where you use it: free lessons
- Answer Staff Questions from Your Own Docs using n8n + Pinecone (n8n, 13 min)
- Gmail AI Triage: Auto-Label Every Email and Draft Replies (n8n, 18 min)
- n8n AI Agent with Tools: Check Google Calendar, Book It and Log It (n8n, 11 min)
Frequently asked questions
- Is LangChain free?
- The LangChain framework is open source and free to use. The language models it calls, and the company's hosted extras, are separate.
- Do I need to know LangChain to use n8n's AI Agent?
- No. n8n turns LangChain's parts into nodes you add with clicks. Knowing the names just makes the docs easier to read.
- What is a chain in LangChain?
- A set of steps that runs in a fixed order, such as fill in a prompt, send it to a model, then format the answer.