LangChain Architecture and Core Abstractions
Understand LangChain's component model including LLMs, ChatModels, PromptTemplates, OutputParsers, and Runnables, and how they compose into pipelines.
What LangChain Actually Is
LangChain is a framework for building applications powered by language models. Rather than writing raw API calls and glue code yourself, LangChain provides reusable components that snap together into pipelines. It supports multiple LLM providers (OpenAI, Anthropic, Cohere, local models) through a unified interface, so switching providers requires minimal code changes.
The Component Model Overview
LangChain organizes its building blocks into distinct component categories. LLMs and ChatModels wrap model providers. PromptTemplates manage dynamic prompt construction. OutputParsers transform raw model text into structured Python objects. Runnables are the universal interface that ties everything together into composable pipelines.
All lessons in this course
- LangChain Architecture and Core Abstractions
- Building Chains with LCEL
- Branching and Parallel Chains
- Streaming Output in LangChain