LangChain vs. LangGraph: When to Reach for Each

LangChain shines when the workflow is mostly linear: ingest, transform, retrieve, synthesize. LangGraph shines when you need cycles, branching, and explicit state machines — the bread-and-butter of agent systems.

A simple heuristic If you can draw your pipeline as a straight line on a napkin, LangChain is enough. If your napkin sketch needs arrows that loop back, reach for LangGraph.

Observability first Either way, plug into LangSmith from day one. The cost of retroactively adding tracing is far higher than the cost of turning it on early.

Agents that look impressive in demos collapse in production because nobody saw the failure modes.