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LangChain

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Open-source framework for LLM apps with LangSmith observability

Updated Dec 7, 2025
AI Framework/LibraryOpen SourceAll platforms
Last reviewed: Dec 7, 2025Details verified against vendor changelogs and hands-on usage.
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Pricing and features change frequently—confirm on the vendor site.

About

LangChain is an open-source framework for building LLM apps with composable chains, agents, tools, and RAG. It supports Python and TypeScript, integrates with major model providers and vector stores, and pairs with LangSmith for tracing, monitoring, and evals.

Key Features

  • Composable chains for multi-step workflows
  • Agent framework with tool use
  • RAG (Retrieval Augmented Generation)
  • Memory and retrieval for RAG
  • Multi-model/provider support
  • LangSmith tracing, monitoring, and evals
  • LangGraph for stateful agents
  • Extensive integrations ecosystem

Use Cases

  • RAG applications with document Q&A
  • Multi-agent systems
  • Chatbots with memory
  • Tool-using AI agents
  • Complex AI workflows
  • Production LLM applications

Technical Details

Languages

PythonJavaScript/TypeScript

AI Models

Any LLM via unified interface

Integrations

OpenAIAnthropicGoogleAzure OpenAIVector DBs (Pinecone, Weaviate, etc.)100+ integrations

Frequently Asked Questions

What is LangChain?

LangChain is an open-source framework for building LLM apps with composable chains, agents, tools, and RAG. It supports Python and TypeScript, integrates with major model providers and vector stores, and pairs with LangSmith for tracing, monitoring, and evals.

Is LangChain free?

Yes, LangChain is open source and free to use. Full framework access, All components, Community support

What programming languages does LangChain support?

LangChain supports 2+ programming languages including Python, JavaScript/TypeScript.

What AI models does LangChain use?

LangChain is powered by Any LLM via unified interface.

What platforms does LangChain support?

LangChain is available on All platforms.

What can LangChain do?

LangChain provides AI chat, agentic/autonomous mode. Key features include: Composable chains for multi-step workflows, Agent framework with tool use, RAG (Retrieval Augmented Generation).

Pricing

Free (Open Source)

$0
  • Full framework access
  • All components
  • Community support
  • Production use

LangSmith Developer

Free (1 seat, 5k traces/month included)
  • Tracing and monitoring
  • Evals (online/offline)
  • Dataset collection and annotation queue
  • Dev deployment included

LangSmith Plus

$39/user/month (up to 10 seats, 10k traces/month included)
  • Everything in Developer
  • Team seats (up to 10)
  • Deployments with agent runs and uptime billing

LangSmith Enterprise

Contact sales
  • Custom seats and limits
  • Enterprise support and security

Company

Name
LangChain (Harrison Chase)
Founded
2022
Location
San Francisco, CA
Users
Hundreds of thousands of developers

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