Python / JS
LangChain
Compose chains, tools and agents
by langchain-ai · MIT
LLM / RAG frameworkLLM app frameworkMITCloud-optionalPython / JSIntermediate
From the README
Install
uv add langchain
- Deep Agents — Build agents that can plan, use subagents, and leverage file systems for complex tasks
- LangGraph — Build agents that can reliably handle complex tasks with our low-level agent orchestration framework
- Integrations — Chat & embedding models, tools & toolkits, and more
- LangSmith — Agent evals, observability, and debugging for LLM apps
- LangSmith Deployment — Deploy and scale agents with a purpose-built platform for long-running, stateful workflows
Excerpts from the project README on GitHub. Copyright and licensing remain with the respective authors.
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🚀 Latest release ·
What is LangChain?
LangChain is a framework for building LLM applications by composing prompts, models, tools, memory and agents, with a vast ecosystem of integrations.
Why people choose LangChain
- Huge ecosystem of integrations
- Building blocks for chains, tools and agents
- Python and JavaScript support
LangChain at a glance
| Category | LLM / RAG framework |
| Type | LLM app framework |
| License | MIT |
| Runs locally | Cloud-optional |
| Built with | Python / JS |
| Skill level | Intermediate |
| Best for | developers building tool-using LLM apps |
Latest releases
Open-source alternatives to LangChain
Other open-source llm / rag framework tools worth comparing:
LlamaIndexThe data framework for RAG
HaystackProduction pipelines for search and RAG
DSPyProgram — not prompt — language models
txtaiAll-in-one embeddings database
RAGFlowDeep-document-understanding RAG
Semantic KernelMicrosoft's enterprise agent frameworkGraphRAGRAG that builds a knowledge graph first
LiteLLMOne API for 100+ LLM providers
InstructorReliable structured outputs from LLMs
OutlinesGuarantee valid JSON and grammars
GuidanceInterleave control and generation
LLMWareEnterprise RAG with small specialised models
FlashRankUltra-light reranking for better RAG
Sentence TransformersThe standard way to make embeddings
RagasMeasure whether your RAG is any good
PromptfooUnit tests for your prompts
LangfuseSee what your LLM app actually did
PhoenixTrace, evaluate and debug LLM appsLangChain head-to-head
LangChain vs LlamaIndexLangChain vs HaystackLangChain vs DSPyLangChain vs txtaiLangChain vs RAGFlowLangChain vs Semantic KernelLangChain vs GraphRAGLangChain vs LiteLLMLangChain vs InstructorLangChain vs OutlinesLangChain vs GuidanceLangChain vs LLMWareLangChain vs FlashRankLangChain vs Sentence TransformersLangChain vs RagasLangChain vs PromptfooLangChain vs LangfuseLangChain vs Phoenix
FAQ
Is LangChain free?
LangChain is free and open-source (MIT license), so you can use, self-host and modify it at no cost.
Can I run LangChain locally?
LangChain can be used locally or in the cloud depending on your setup.
What is the best alternative to LangChain?
Popular open-source alternatives include LlamaIndex, Haystack, DSPy. See the comparisons above to choose.
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