LangChain
Also known as: LangChain.js, LangChain Python
In one sentence
An open-source framework for building applications powered by large language models, providing tools for chaining prompts, managing memory, connecting to external tools, and creating AI agents.
Explain like I'm 12
Like LEGO blocks for AI apps—it gives you pre-built pieces (prompt templates, memory, tool connectors) that snap together so you can build chatbots and AI assistants without starting from scratch.
In context
LangChain simplifies complex AI workflows that would otherwise require hundreds of lines of custom code. Instead of manually coding prompt sequences and API integrations, developers use LangChain's components: chains (sequences of LLM calls), agents (LLMs that decide which tools to use), memory (conversation history tracking), and retrievers (for pulling relevant documents in RAG systems). It supports both Python and JavaScript, making it accessible across web and backend development.
See also
Related Guides
Learn more about LangChain in these guides:
Orchestration Options: LangChain, LlamaIndex, and Beyond
IntermediateFrameworks for building AI workflows. Compare LangChain, LlamaIndex, Haystack, and custom solutions.
12 min readAgents & Tools: What They're Good For (and What to Watch For)
IntermediateUnderstand AI agents that use tools to complete tasks. When they work, when they fail, and how to use them safely.
10 min readContext Engineering: Beyond Prompt Engineering
IntermediateThe 2026 paradigm shift from crafting prompts to engineering entire context windows. Learn to design the informational environment that makes AI systems reliable.
12 min read