# LangGraph.js

A framework for building agents as a graph of steps with shared, saved state.

AI developers · Part 06: LangChain / LangGraph · Card 7 of 14 · Last updated 2026-10-13

## Analogy

XState or a Redux reducer, but each state transition might call an LLM.

## In an agent

Reach for it when your agent needs branches, approvals, memory or recovery after a crash.

## Practice

### Flashcards

- **Interview: what does LangGraph add to LangChain?** Explicit graphs with state, checkpoints, interrupts and routing, so complex agents are easier to control.

### Interview questions

**Why LangChain / LangGraph, and why not?**

- LangChain saves boilerplate for RAG: loaders, splitters, retrievers.
- LangGraph gives state, checkpoints, interrupts and routing for complex agents.
- For simple cases, skip them and use the SDK directly to avoid needless abstraction.

## Questions people ask

### What is LangGraph.js?

LangGraph.js is a framework for building agents as a graph of steps that share saved state. Nodes are functions, edges decide what runs next, and a checkpointer stores the state after each step. It suits agents that need branches, human approvals, memory across sessions or recovery after a crash.

### What is the difference between LangChain and LangGraph?

LangChain gives you building blocks: model wrappers, loaders, splitters, retrievers and tools. LangGraph is for orchestration: it runs those blocks as a graph with shared state, branching, checkpoints and interrupts. Many projects use LangChain parts inside LangGraph nodes. A simple RAG pipeline may need only LangChain.

## Related concepts

- [LangChain.js](https://studyvisually.com/learn/tech/ai-developers/langchain-langgraph/langchain)
- [Graph state](https://studyvisually.com/learn/tech/ai-developers/langchain-langgraph/graph-state)
- [Conditional edges](https://studyvisually.com/learn/tech/ai-developers/langchain-langgraph/conditional-edges)
- [Checkpointing](https://studyvisually.com/learn/tech/ai-developers/langchain-langgraph/checkpointing)

Web page: https://studyvisually.com/learn/tech/ai-developers/langchain-langgraph/langgraph
Study this card in the app: https://studyvisually.com/app/learn?category=ai-developers&card=langgraph