LangChain

The most widely used framework for building LLM applications and AI agents.

Open Source Coding & Development
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What is LangChain?

LangChain is the dominant open-source framework for LLM applications: chains, agents, tools, memory, and 100+ integrations across Python and TypeScript. It underpins a huge share of production AI apps and agent startups. With 147K stars and daily commits, it remains the default starting point for agent development.

Key features

  • Chains, agents, and tools primitives
  • 100+ model and service integrations
  • Memory and retrieval (RAG) building blocks
  • Python and TypeScript SDKs
  • LangGraph and LangSmith ecosystem tie-in

Watch: LangChain tutorial

LangChain Tutorial for Beginners | LangChain Projects | LangChain Crash Course 2026 LangChain Tutorial for Beginners | LangChain Projects | LangChain Crash Course 2026 — Simplilearn

Video by Simplilearn on YouTube — plays here without leaving this page.

Pros

  • Largest LLM-framework ecosystem by far
  • Integrations for almost every provider
  • Huge docs, tutorials, and community

Cons

  • Abstraction layers can obscure debugging
  • Fast-moving APIs introduce breaking changes
  • Heavier than minimal agent libraries

LangChain at a glance

PricingOpen Source
CategoryCoding & Development
Platformsapi
CompanyLangChain
Official websitegithub.com
frameworkllm-appsai-agentsragpython

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The right coding tool depends on where you write code and how much of your codebase it can understand. IDE integration is the first filter — a tool that lives in your editor, sees your project files and respects your stack will help far more than a general chatbot you paste snippets into. Look for accurate completions, clear explanations of suggested changes, and strong refactoring and debugging support for your main languages. Privacy deserves real attention: check whether your code is used for training, and whether a self-hosted or enterprise option exists for sensitive projects. Price against the hours it actually saves — most developers feel the difference within the first week of real use.

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LangChain FAQs

What is LangChain?

LangChain is the dominant open-source framework for LLM applications: chains, agents, tools, memory, and 100+ integrations across Python and TypeScript. It underpins a huge share of production AI apps and agent startups. With 147K stars and daily commits, it remains the default starting point for agent development.

What are the main features of LangChain?

LangChain offers Chains, agents, and tools primitives, 100+ model and service integrations, Memory and retrieval (RAG) building blocks, Python and TypeScript SDKs and LangGraph and LangSmith ecosystem tie-in.

How much does LangChain cost?

LangChain is open source, so the software itself is free to download, use and self-host. Your only costs are the infrastructure you run it on and any paid services you connect to it.

What are the pros and cons of LangChain?

Strengths of LangChain include Largest LLM-framework ecosystem by far; Integrations for almost every provider; Huge docs, tutorials, and community. On the downside, Abstraction layers can obscure debugging; Fast-moving APIs introduce breaking changes; Heavier than minimal agent libraries.