LangGraph

LangGraph, from the LangChain team, is an open-source framework for building agents as stateful graphs. Instead of a single prompt loop, you model the application as nodes and edges, which gives precise control over branching, loops, and how state moves through the system.

The honest fit for this directory: LangGraph is among the most developer-heavy tools listed. It is for engineers building durable, production agent applications, not for a founder who wants to get a task done without code. If you are looking to automate a job in your business, the no-code automation and assistant categories are the place to start, not here.

For the builder, LangGraph is strong precisely because it is low-level: built-in persistence and checkpointing, token-level streaming, and human-in-the-loop pauses, available in both Python and JavaScript and integrated with LangSmith for observability. The library is free; a managed LangGraph Platform adds hosted deployment. The trade is the learning curve and the fact that its graph abstractions are overkill for anything simple, so reach for it only when you genuinely need that control.