transitions
A lightweight, object-oriented Python state machine implementation with many extensions.
Decision gist · record as of 2026-08-14
Yes, if you need a straightforward state machine for modeling workflows or stateful behavior. The library is stable, permissively licensed, and has low install friction. However, note that maintenance is aging (last release July 2025, no recent commits); if you require active development or frequent updates, verify that the project's pace aligns with your needs. No known security vulnerabilities.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Low install friction; pure Python wheel with only six as a runtime dependency.
- Maintenance status is aging—last release was 2025-07-02 and the repository shows no recent activity, though it remains unarchived with a substantial GitHub presence.
License · maintenance · safety
MIT (permissive) — MIT license is permissive; you can use, modify, and distribute this package freely in commercial and private projects with minimal restrictions.
last release 2025-07-02 (408 days) · last repo commit 2025-09-11 · 6,579 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 2,944,762 downloads/mo, #2,814 on PyPI
Alternatives
Verify before relying
from transitions import Machine
class Matter:
pass
lump = Matter()
machine = Machine(model=lump, states=['solid', 'liquid'], initial='solid')
machine.add_transition(trigger='melt', source='solid', dest='liquid')
lump.melt() # Triggers transition
print(lump.state) # 'liquid'- Whether the aging maintenance status (last release 2025-07-02, no recent commits) affects stability or security for new projects.
- Whether extensions mentioned in the description (e.g., Diagrams) are included or require separate installation.
What it is and what it does
Transitions is a state machine library that embeds finite-state behavior into Python objects. You define states and transitions between them, then attach the machine to a model object; the library automatically creates trigger methods that move the object between states. It supports callbacks (actions executed before, after, or during transitions), conditional transitions, and wildcard source states.
The library is designed for modeling workflows, event-driven systems, and stateful processes where you need to enforce valid state changes and execute side effects when transitions occur. It's built on top of six for Python 2/3 compatibility and has a minimal dependency footprint.
Use it for
- Model application workflows where objects move through defined states (e.g., order processing: pending → shipped → delivered).
- Implement event-driven systems where triggers initiate state changes and callbacks execute business logic.
- Build game or simulation logic where entities have discrete states and rules governing transitions between them.
- Enforce state validity in domain objects by preventing invalid transitions and logging state changes.
- Create interactive state machines for chatbots, form wizards, or multi-step processes.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you need a straightforward state machine for modeling workflows or stateful behavior.
The library is stable, permissively licensed, and has low install friction. However, note that maintenance is aging (last release July 2025, no recent commits); if you require active development or frequent updates, verify that the project's pace aligns with your needs. No known security vulnerabilities.
Install
transitions on PyPI
Before you install
Low install friction; pure Python wheel with only six as a runtime dependency. Maintenance status is aging—last release was 2025-07-02 and the repository shows no recent activity, though it remains unarchived with a substantial GitHub presence.
License in practice
MIT license is permissive; you can use, modify, and distribute this package freely in commercial and private projects with minimal restrictions.
Quickstart
from transitions import Machine
class Matter:
pass
lump = Matter()
machine = Machine(model=lump, states=['solid', 'liquid'], initial='solid')
machine.add_transition(trigger='melt', source='solid', dest='liquid')
lump.melt() # Triggers transition
print(lump.state) # 'liquid'Verify before relying
- Whether the aging maintenance status (last release 2025-07-02, no recent commits) affects stability or security for new projects.
- Whether extensions mentioned in the description (e.g., Diagrams) are included or require separate installation.
Package facts
| License | MIT permissive |
| Python support | Not specified |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 1 packagesix |
| Maintenance | Aging 408 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 2,944,762 / month, #2,814 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | License :: OSI Approved :: MIT LicenseProgramming Language :: Python :: 2Programming Language :: Python :: 2.7Programming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9 |
Evidence: transitions-0.9.3-py2.py3-none-any.whl
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