Burr

Burr is a Python framework for building stateful AI applications and agents, modeling them as state machines of actions and transitions defined with plain functions and decorators. It covers chatbots, agents, and simulations without a domain-specific language.

It persists state to disk, databases, or custom backends, supports checkpoints, human-in-the-loop, parallel execution, and branching, and ships a built-in UI for real-time monitoring, tracing, and replay. It integrates with OpenAI, Anthropic, LangChain, FastAPI, and Pydantic. Apache 2.0 (incubating), originally built by DAGWorks.