LangChain is an open-source framework for building applications powered by large language models (LLMs). It provides a composable set of components for chaining LLM calls with tools, memory, retrieval, and agents — enabling developers to build RAG (retrieval-augmented generation) systems, chatbots, and autonomous agents. LangChain supports OpenAI, Anthropic, Google, and 50+ other LLM providers and has become the most widely used LLM application framework.
LangChain
The leading framework for building LLM applications.
Best for: Developers building LLM-powered applications, RAG systems and AI agents who want a widely supported framework.
- Free plan
4.4/5 ratingEditorial score 84/100langchain.com
Entry plan
Free forever
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Editorial score84/100
The editorial note
What to know about LangChain
Is it right for you?
Who LangChain suits
Choose it if
- Developers building LLM-powered applications, RAG systems and AI agents who want a widely supported framework.
Look elsewhere if
- Teams wanting a simpler, more stable AI orchestration framework — LlamaIndex or Instructor provide focused, less complex alternatives for RAG and structured extraction respectively
What you get
Key features
- LLM chaining and prompt templating
- Retrieval-Augmented Generation (RAG)
- Vector store integrations (50+)
- Autonomous agents with tool use
- Memory for conversational context
- LangGraph for stateful multi-agent workflows
- LangSmith for tracing and evaluation
- 50+ LLM provider integrations
Works with
Integrations8
What it costs
Pricing
| Plan | Price | What it includes |
|---|---|---|
| Open Source | Free forever | LLM application framework — free and open-source |
| LangSmith Developer | Free (5K traces/month)Billed monthly | LLM observability and testing with 5,000 free traces |
| LangSmith Plus | $39 / monthBilled monthly | 100K traces, collaboration, and advanced evaluation tools |
Prices are recorded from the vendor's public pricing page and can change. Check before you buy.
The trade-off
Pros and cons
Pros
- Most popular LLM framework — huge community, tutorials, and integrations for every use case
- Supports 50+ LLM providers including OpenAI, Anthropic, Google, and local models
- LangSmith observability platform traces LLM calls for debugging and evaluation
- Composable chains and agents make complex multi-step AI workflows easy to build
- LangGraph enables building stateful, multi-agent workflows with graph-based orchestration
Cons
- Frequent breaking API changes make version pinning and maintenance challenging
- Abstraction overhead can make simple tasks more complex than necessary
- Documentation is sometimes incomplete or outdated for newer features
- LangSmith observability requires additional setup and cost for production monitoring
Quick read
At a glance
- Category
- AI Tools
- Pricing model
- Free
- Entry plan
- Free forever
- Free plan
- Available
- Free trial
- Not listed
- Website
- langchain.com
The verdict
Our take on LangChain
The essential framework for LLM applications — breadth of integrations and community support are unmatched.
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