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.

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Simple, powerful Python API

Build anything from chatbots to multi-agent systems with a clean, composable interface.

chatbot.py

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})

Python 3.12UTF-8burr >= 0.30

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

LLM

Anthropic

LLM

LangChain

Framework

Hamilton

Framework

Streamlit

UI

OpenAI

LLM

Anthropic

LLM

LangChain

Framework

Hamilton

Framework

Streamlit

UI

OpenAI

LLM

Anthropic

LLM

LangChain

Framework

Hamilton

Framework

Streamlit

UI

OpenAI

LLM

Anthropic

LLM

LangChain

Framework

Hamilton

Framework

Streamlit

UI

FastAPI

Serving

Haystack

Framework

Instructor

LLM

Pydantic

Validation

PostgreSQL

Storage

FastAPI

Serving

Haystack

Framework

Instructor

LLM

Pydantic

Validation

PostgreSQL

Storage

FastAPI

Serving

Haystack

Framework

Instructor

LLM

Pydantic

Validation

PostgreSQL

Storage

FastAPI

Serving

Haystack

Framework

Instructor

LLM

Pydantic

Validation

PostgreSQL

Storage

View all integrations

Trusted by engineers worldwide

See what developers and teams are saying about Burr.

P

Peanut Robotics

W

Watto.ai

P

Paxton AI

P

Provectus

T

TaskHuman

“After evaluating several other obfuscating LLM frameworks, their elegant yet comprehensive state management solution proved to be the powerful answer to rolling out robots driven by AI decision making.”

A

Ashish Ghosh

CTO, Peanut Robotics

“Using Burr is a no-brainer if you want to build a modular AI application. It is so easy to build with and I especially love their UI which makes debugging a piece of cake. And the always ready to help team is the cherry on top.”

I

Ishita

Founder, Watto.ai

“I just came across Burr and I'm like WOW, this seems like you guys predicted this exact need when building this. No weird esoteric concepts just because it's AI.”

M

Matthew Rideout

Staff Software Engineer, Paxton AI

“Burr's state management part is really helpful for creating state snapshots and build debugging, replaying and even building evaluation cases around that.”

R

Rinat Gareev

Senior Solutions Architect, Provectus

“I have been using Burr over the past few months, and compared to many agentic LLM platforms out there (e.g. LangChain, CrewAi, AutoGen, Agency Swarm, etc), Burr provides a more robust framework for designing complex behaviors.”

H

Hadi Nayebi

Co-founder, CognitiveGraphs

“Moving from LangChain to Burr was a game-changer! It took me just a few hours to get started with Burr, compared to the days and weeks I spent trying to navigate LangChain. I pitched Burr to my teammates, and we pivoted our entire codebase to it.”

A

Aditya K.

DS Architect, TaskHuman

“Of course, you can use it [LangChain], but whether it's really production-ready and improves the time from code-to-prod, we've been doing LLM apps for two years, and the answer is no. Honestly, take a look at Burr. Thank me later.”

R

Reddit User

Developer, r/LocalLlama

“After evaluating several other obfuscating LLM frameworks, their elegant yet comprehensive state management solution proved to be the powerful answer to rolling out robots driven by AI decision making.”

A

Ashish Ghosh

CTO, Peanut Robotics

“Using Burr is a no-brainer if you want to build a modular AI application. It is so easy to build with and I especially love their UI which makes debugging a piece of cake. And the always ready to help team is the cherry on top.”

I

Ishita

Founder, Watto.ai

“I just came across Burr and I'm like WOW, this seems like you guys predicted this exact need when building this. No weird esoteric concepts just because it's AI.”

M

Matthew Rideout

Staff Software Engineer, Paxton AI

“Burr's state management part is really helpful for creating state snapshots and build debugging, replaying and even building evaluation cases around that.”

R

Rinat Gareev

Senior Solutions Architect, Provectus

“I have been using Burr over the past few months, and compared to many agentic LLM platforms out there (e.g. LangChain, CrewAi, AutoGen, Agency Swarm, etc), Burr provides a more robust framework for designing complex behaviors.”

H

Hadi Nayebi

Co-founder, CognitiveGraphs

“Moving from LangChain to Burr was a game-changer! It took me just a few hours to get started with Burr, compared to the days and weeks I spent trying to navigate LangChain. I pitched Burr to my teammates, and we pivoted our entire codebase to it.”

A

Aditya K.

DS Architect, TaskHuman

“Of course, you can use it [LangChain], but whether it's really production-ready and improves the time from code-to-prod, we've been doing LLM apps for two years, and the answer is no. Honestly, take a look at Burr. Thank me later.”

R

Reddit User

Developer, r/LocalLlama

“After evaluating several other obfuscating LLM frameworks, their elegant yet comprehensive state management solution proved to be the powerful answer to rolling out robots driven by AI decision making.”

A

Ashish Ghosh

CTO, Peanut Robotics

“Using Burr is a no-brainer if you want to build a modular AI application. It is so easy to build with and I especially love their UI which makes debugging a piece of cake. And the always ready to help team is the cherry on top.”

I

Ishita

Founder, Watto.ai

“I just came across Burr and I'm like WOW, this seems like you guys predicted this exact need when building this. No weird esoteric concepts just because it's AI.”

M

Matthew Rideout

Staff Software Engineer, Paxton AI

“Burr's state management part is really helpful for creating state snapshots and build debugging, replaying and even building evaluation cases around that.”

R

Rinat Gareev

Senior Solutions Architect, Provectus

“I have been using Burr over the past few months, and compared to many agentic LLM platforms out there (e.g. LangChain, CrewAi, AutoGen, Agency Swarm, etc), Burr provides a more robust framework for designing complex behaviors.”

H

Hadi Nayebi

Co-founder, CognitiveGraphs

“Moving from LangChain to Burr was a game-changer! It took me just a few hours to get started with Burr, compared to the days and weeks I spent trying to navigate LangChain. I pitched Burr to my teammates, and we pivoted our entire codebase to it.”

A

Aditya K.

DS Architect, TaskHuman

“Of course, you can use it [LangChain], but whether it's really production-ready and improves the time from code-to-prod, we've been doing LLM apps for two years, and the answer is no. Honestly, take a look at Burr. Thank me later.”

R

Reddit User

Developer, r/LocalLlama

“After evaluating several other obfuscating LLM frameworks, their elegant yet comprehensive state management solution proved to be the powerful answer to rolling out robots driven by AI decision making.”

A

Ashish Ghosh

CTO, Peanut Robotics

“Using Burr is a no-brainer if you want to build a modular AI application. It is so easy to build with and I especially love their UI which makes debugging a piece of cake. And the always ready to help team is the cherry on top.”

I

Ishita

Founder, Watto.ai

“I just came across Burr and I'm like WOW, this seems like you guys predicted this exact need when building this. No weird esoteric concepts just because it's AI.”

M

Matthew Rideout

Staff Software Engineer, Paxton AI

“Burr's state management part is really helpful for creating state snapshots and build debugging, replaying and even building evaluation cases around that.”

R

Rinat Gareev

Senior Solutions Architect, Provectus

“I have been using Burr over the past few months, and compared to many agentic LLM platforms out there (e.g. LangChain, CrewAi, AutoGen, Agency Swarm, etc), Burr provides a more robust framework for designing complex behaviors.”

H

Hadi Nayebi

Co-founder, CognitiveGraphs

“Moving from LangChain to Burr was a game-changer! It took me just a few hours to get started with Burr, compared to the days and weeks I spent trying to navigate LangChain. I pitched Burr to my teammates, and we pivoted our entire codebase to it.”

A

Aditya K.

DS Architect, TaskHuman

“Of course, you can use it [LangChain], but whether it's really production-ready and improves the time from code-to-prod, we've been doing LLM apps for two years, and the answer is no. Honestly, take a look at Burr. Thank me later.”

R

Reddit User

Developer, r/LocalLlama

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