Build reliable AI agents and applications
Apache Burr (Incubating) makes it easy to develop applications that make decisions, from simple chatbots to complex multi-agent systems. Pure Python, no magic.
Simple, powerful Python API
Build anything from chatbots to multi-agent systems with a clean, composable interface.
from burr.core import action, State, ApplicationBuilder
@action(reads=["messages"], writes=["messages"])
def chat(state: State, llm_client) -> State:
response = llm_client.chat(state["messages"])
return state.update(
messages=[*state["messages"], response]
)
app = (
ApplicationBuilder()
.with_actions(chat)
.with_transitions(("chat", "chat"))
.with_state(messages=[])
.with_tracker("local")
.build()
)
app.run(halt_after=["chat"], inputs={"llm_client": client})Everything you need to build AI applications
Burr provides the building blocks for reliable, observable, and testable AI-powered applications.
Simple Python API
Define your application as a set of actions and transitions. No DSL, no YAML — just Python functions and decorators.
Built-in Observability
The Burr UI lets you monitor, debug, and trace every step of your application in real time. See state changes as they happen.
Persistence & State Management
Automatically persist state to disk, databases, or custom backends. Resume applications from where they left off.
Human-in-the-Loop
Pause execution and wait for human input at any step. Perfect for approval workflows and interactive agents.
Branching & Parallelism
Run actions in parallel, fan out / fan in, and build complex DAGs. Compose sub-applications for modular design.
Testing & Replay
Replay past runs, unit test individual actions, and validate state transitions. Build confidence in your AI systems.
Works with your stack
Burr integrates with the tools and frameworks you already use. No lock-in, no wrappers.
OpenAI
LLMAnthropic
LLMLangChain
FrameworkHamilton
FrameworkStreamlit
UIOpenAI
LLMAnthropic
LLMLangChain
FrameworkHamilton
FrameworkStreamlit
UIOpenAI
LLMAnthropic
LLMLangChain
FrameworkHamilton
FrameworkStreamlit
UIOpenAI
LLMAnthropic
LLMLangChain
FrameworkHamilton
FrameworkStreamlit
UIFastAPI
ServingHaystack
FrameworkInstructor
LLMPydantic
ValidationPostgreSQL
StorageFastAPI
ServingHaystack
FrameworkInstructor
LLMPydantic
ValidationPostgreSQL
StorageFastAPI
ServingHaystack
FrameworkInstructor
LLMPydantic
ValidationPostgreSQL
StorageFastAPI
ServingHaystack
FrameworkInstructor
LLMPydantic
ValidationPostgreSQL
StorageTrusted by engineers worldwide
See what developers and teams are saying about Burr.
“Burr completely changed how we build AI agents. The state management and observability are game-changers for production systems.”
“We moved from a tangled mess of LangChain callbacks to clean, testable Burr actions. Our team velocity doubled.”
“The Burr UI alone is worth it. Being able to replay and debug agent runs saved us countless hours of debugging.”
“Human-in-the-loop was trivial to add with Burr. We went from prototype to production approval workflow in a day.”
“Pure Python, no magic, no hidden abstractions. Burr lets us build exactly what we need without fighting the framework.”
“Persistence and replay are incredible for debugging complex multi-step agents. Burr makes the hard parts easy.”
“Burr completely changed how we build AI agents. The state management and observability are game-changers for production systems.”
“We moved from a tangled mess of LangChain callbacks to clean, testable Burr actions. Our team velocity doubled.”
“The Burr UI alone is worth it. Being able to replay and debug agent runs saved us countless hours of debugging.”
“Human-in-the-loop was trivial to add with Burr. We went from prototype to production approval workflow in a day.”
“Pure Python, no magic, no hidden abstractions. Burr lets us build exactly what we need without fighting the framework.”
“Persistence and replay are incredible for debugging complex multi-step agents. Burr makes the hard parts easy.”
“Burr completely changed how we build AI agents. The state management and observability are game-changers for production systems.”
“We moved from a tangled mess of LangChain callbacks to clean, testable Burr actions. Our team velocity doubled.”
“The Burr UI alone is worth it. Being able to replay and debug agent runs saved us countless hours of debugging.”
“Human-in-the-loop was trivial to add with Burr. We went from prototype to production approval workflow in a day.”
“Pure Python, no magic, no hidden abstractions. Burr lets us build exactly what we need without fighting the framework.”
“Persistence and replay are incredible for debugging complex multi-step agents. Burr makes the hard parts easy.”
“Burr completely changed how we build AI agents. The state management and observability are game-changers for production systems.”
“We moved from a tangled mess of LangChain callbacks to clean, testable Burr actions. Our team velocity doubled.”
“The Burr UI alone is worth it. Being able to replay and debug agent runs saved us countless hours of debugging.”
“Human-in-the-loop was trivial to add with Burr. We went from prototype to production approval workflow in a day.”
“Pure Python, no magic, no hidden abstractions. Burr lets us build exactly what we need without fighting the framework.”
“Persistence and replay are incredible for debugging complex multi-step agents. Burr makes the hard parts easy.”
Join the community
Get help, share your projects, and contribute to the future of Burr.