observable
minimalist event system
Decision gist · record as of 2026-08-14
Yes, for small to medium projects that need lightweight event handling without external dependencies. The API is simple and stable. However, do not use for new projects requiring ongoing maintenance or Python version support beyond 3.7—the package is abandoned and will not receive updates. Consider it only when you need a minimal, self-contained event system and can tolerate no future fixes.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.5 or later; Python 2 is not supported.
- Installation is straightforward with no runtime dependencies.
- However, the package has been abandoned since early 2020 with no commits or releases in nearly six years, so maintenance and security updates are not expected.
License · maintenance · safety
MIT (permissive) — MIT license permits free use, modification, and distribution with minimal restrictions, making it suitable for both open-source and proprietary projects.
last release 2018-09-20 (2885 days) · last repo commit 2020-01-19 · 86 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 156,647 downloads/mo, #10,779 on PyPI
Alternatives
Verify before relying
pip install observable
from observable import Observable
obs = Observable()
@obs.on("error")
def error_handler(message):
print(f"Error: {message}")
obs.trigger("error", "Something went wrong")- Whether the package works reliably with Python versions released after 3.7 (last tested version in classifiers)
- Whether abandonment has led to compatibility issues with modern Python ecosystems
What it is and what it does
Observable is a minimalist event system for Python that lets you attach handler functions to named events and trigger them on demand. It supports both decorator-style registration (`@obs.on("event_name")`) and direct method calls, and provides utilities to remove handlers, check registration status, and manage events. The package has no external dependencies and installs cleanly.
Typical usage involves creating an Observable instance, registering event handlers, and calling `trigger()` to invoke them with arbitrary arguments. It's designed for simple event-driven architectures where you need decoupled communication between different parts of your code—for example, error handling, state changes, or user actions. The package is stable and production-ready in its API, but has not been maintained since early 2020.
Use it for
- Decouple error handling from core logic by registering error handlers that trigger on specific failure conditions.
- Build simple plugin systems where external code registers handlers for application lifecycle events.
- Implement state-change notifications so multiple parts of an application react when data changes.
- Create callback chains for asynchronous workflows without introducing heavy async/await complexity.
- Prototype event-driven architectures before committing to a larger framework.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, for small to medium projects that need lightweight event handling without external dependencies.
The API is simple and stable. However, do not use for new projects requiring ongoing maintenance or Python version support beyond 3.7—the package is abandoned and will not receive updates. Consider it only when you need a minimal, self-contained event system and can tolerate no future fixes.
Install
observable on PyPI
Before you install
Installation is straightforward with no runtime dependencies. However, the package has been abandoned since early 2020 with no commits or releases in nearly six years, so maintenance and security updates are not expected.
Requires Python 3.5 or later; Python 2 is not supported.
License in practice
MIT license permits free use, modification, and distribution with minimal restrictions, making it suitable for both open-source and proprietary projects.
Quickstart
pip install observable
from observable import Observable
obs = Observable()
@obs.on("error")
def error_handler(message):
print(f"Error: {message}")
obs.trigger("error", "Something went wrong")Verify before relying
- Whether the package works reliably with Python versions released after 3.7 (last tested version in classifiers)
- Whether abandonment has led to compatibility issues with modern Python ecosystems
Package facts
| License | MIT permissive |
| Python support | Not specified |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | None |
| Maintenance | Abandoned 2,885 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 156,647 / month, #10,779 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseNatural Language :: EnglishOperating System :: OS IndependentProgramming Language :: Python :: 3Programming Language :: Python :: 3.5Programming Language :: Python :: 3.6Programming Language :: Python :: 3.7Programming Language :: Python :: ImplementationProgramming Language :: Python :: Implementation :: CPythonTopic :: Software Development :: Libraries :: Python Modules |
Evidence: observable-1.0.3-py2.py3-none-any.whl
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