cong-cu Intermediate
What is LangChain?
An open-source framework designed to help developers build context-aware AI applications by connecting LLMs with external data sources and tools.
Updated: November 11, 2026 · 1 min read
LangChain is an open-source development framework (available for Python and TypeScript/JavaScript) that simplifies building applications powered by large language models (LLMs). Rather than interacting with models via raw API calls, LangChain provides high-level abstractions to chain components together into complex workflows.
Core Components of LangChain
- Model I/O: Unified interfaces for interacting with diverse LLM providers (OpenAI, Anthropic Claude, Google Gemini, local models) with standardized prompt management.
- Retrieval (RAG): Connectors including Document Loaders, Text Splitters, Embedding models, and integrations with dozens of Vector Stores.
- Chains (LCEL): LangChain Expression Language (LCEL) allows composing sequential prompts, models, and output parsers declaratively.
- Agents & Tool Use: Enables LLMs to reason dynamically, select tools (web search, calculators, database queries), and execute actions iteratively to accomplish a goal.
When to Use LangChain?
✅ Creating enterprise document chatbots with RAG.
✅ Building multi-step AI agents and automations.
✅ Rapidly prototyping AI applications with modular, interchangeable components.
Tags
#langchain#llm#agent#rag#python#javascript
