Automat
Self-service finite-state machines for the programmer on the go.
Decision gist · record as of 2026-08-14
Yes, if you need to model stateful behavior with strict state ordering and want a clean, type-safe API. The permissive MIT license and low install friction make it low-risk. However, the 485-day gap since the last release suggests the project is aging; verify that it meets your Python version requirements (3.9+) and that its approach fits your use case before committing to it as a core dependency.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.9 or later; familiarity with typing.Protocol and state machine concepts recommended.
- Low install friction with a single lightweight runtime dependency (typing_extensions).
- Maintenance status is aging—last release was 485 days ago, though the repository remains active with a recent commit on 2026-01-13 and 647 stars.
License · maintenance · safety
permissive license (permissive) — MIT license (permissive) allows free use, modification, and distribution with minimal restrictions, making it suitable for both open-source and commercial projects.
last release 2025-04-16 (485 days) · last repo commit 2026-01-13 · 647 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 14,296,962 downloads/mo, #1,239 on PyPI
Alternatives
Verify before relying
from automat import TypeMachineBuilder
from typing import Protocol
class MyStateMachine(Protocol):
def event(self) -> None: pass
builder = TypeMachineBuilder(MyStateMachine, CoreData)
state_a = builder.state("state_a")
state_b = builder.state("state_b")
state_a.upon(MyStateMachine.event).to(state_b).returns(None)
machine = builder.build()- Whether the library is actively maintained or in maintenance-only mode given the 485-day gap since last release
- Performance characteristics and scalability limits for complex state machines with many states or transitions
- Real-world adoption patterns and whether it integrates well with async/await workflows
What it is and what it does
Automat is a finite-state machine library that lets you define stateful behavior using Python method calls and type protocols, rather than requiring you to pass generic input objects through a state engine. Instead of scattering conditional logic across methods to track state flags, you declare states and transitions upfront, and the library synthesizes a clean interface that enforces valid state sequences at runtime.
The library targets the common pattern where your code needs to behave differently depending on its state (like a coffee machine that should only brew when it has water, beans, and a closed lid), but your callers should not need to know or care that you've implemented it as a state machine. It depends only on typing_extensions and supports Python 3.9 through 3.13, with full type hints throughout.
Use it for
- Implement protocol-based state machines for complex objects like network connections, protocol handlers, or device controllers that need strict state ordering.
- Build workflow engines or task schedulers where transitions between states must be explicit and validated at definition time.
- Create deterministic finite-state transducers that transform input sequences into output behaviors while maintaining clean, method-call-based APIs.
- Model state-dependent behavior in game logic, UI state management, or embedded systems where invalid state combinations must be impossible.
- Define type-safe state machines for async systems where each state transition can trigger side effects or return computed results.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you need to model stateful behavior with strict state ordering and want a clean, type-safe API.
The permissive MIT license and low install friction make it low-risk. However, the 485-day gap since the last release suggests the project is aging; verify that it meets your Python version requirements (3.9+) and that its approach fits your use case before committing to it as a core dependency.
Install
automat on PyPI
Before you install
Low install friction with a single lightweight runtime dependency (typing_extensions). Maintenance status is aging—last release was 485 days ago, though the repository remains active with a recent commit on 2026-01-13 and 647 stars.
Requires Python 3.9 or later; familiarity with typing.Protocol and state machine concepts recommended.
License in practice
MIT license (permissive) allows free use, modification, and distribution with minimal restrictions, making it suitable for both open-source and commercial projects.
Quickstart
from automat import TypeMachineBuilder
from typing import Protocol
class MyStateMachine(Protocol):
def event(self) -> None: pass
builder = TypeMachineBuilder(MyStateMachine, CoreData)
state_a = builder.state("state_a")
state_b = builder.state("state_b")
state_a.upon(MyStateMachine.event).to(state_b).returns(None)
machine = builder.build()Verify before relying
- Whether the library is actively maintained or in maintenance-only mode given the 485-day gap since last release
- Performance characteristics and scalability limits for complex state machines with many states or transitions
- Real-world adoption patterns and whether it integrates well with async/await workflows
Package facts
| License | permissive license permissive |
| Python support | Supports the current Python release >=3.9 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 1 packagetyping_extensions |
| Maintenance | Aging 485 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 14,296,962 / month, #1,239 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Intended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseOperating System :: OS IndependentProgramming Language :: PythonProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.9Typing :: Typed |
Evidence: automat-25.4.16-py3-none-any.whl
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See also automaton · django-fsm-log · transitions · pynini · outlines-core · python-statemachine · django-fsm-2 · django-fsm · cellpylib · pydantic-graph