LangChain
Most-adopted framework for chaining LLM calls, tools, and agents. Python and JS/TS.
- License
- MIT
- Install
- pip package
- Website
- https://www.langchain.com
- GitHub
- https://github.com/langchain-ai/langchain
pip install langchain
LlamaIndex
Data framework for LLM apps — strongest in document ingestion and RAG pipelines.
- License
- MIT
- Install
- pip package
- Website
- https://www.llamaindex.ai
- GitHub
- https://github.com/run-llama/llama_index
pip install llama-index
When to reach for which
LangChain — Most-adopted framework for chaining LLM calls, tools, and agents. Python and JS/TS.
LlamaIndex — Data framework for LLM apps — strongest in document ingestion and RAG pipelines.
Both sit in the Agent Frameworks category — they're substitutes, not complements. Pick by your install constraint (MCP-native, license, hosting model) and which tag overlap matters most to your stack.