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Rx

Reactive Extensions (Rx) for Python

rx v3.2.0 4.7M downloads/30d#2,249 on PyPI5,019
Permissive license MIT License Active released

What it is and what it does

RxPY is a Python implementation of Reactive Extensions, a library for building programs that handle asynchronous data and events through observable sequences. Instead of polling or callback-based approaches, you represent data streams as Observables and transform them using chainable operators like map, filter, and group_by. The library handles the threading and scheduling complexity, letting you focus on the logic of data transformation.

The package is designed for developers working with event-driven systems, real-time data processing, or any scenario where asynchronous composition matters. It includes over 120 operators and runs on Python 3.6 or above with no external runtime dependencies, making it straightforward to integrate into existing projects.

Use it for:

  • Build real-time data pipelines that transform and filter event streams from APIs or message queues
  • Implement reactive UI updates or event handlers that respond to user input and system events
  • Compose complex asynchronous workflows where multiple data sources need coordinated handling
  • Create event-driven microservices that react to incoming messages or state changes
  • Handle time-based operations like throttling, debouncing, or windowing of event streams

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

RxPY provides a library for composing asynchronous and event-based programs using observable sequences and query operators, allowing developers to represent and manipulate asynchronous data streams in Python.

Yes, if you need reactive programming patterns in Python. RxPY is production-stable, permissively licensed, and has no dependencies. The main consideration is whether observable-based composition fits your use case better than native async/await—RxPY excels at complex event orchestration but adds a learning curve for teams unfamiliar with reactive paradigms.

Install

rx on PyPI

pip

pip install rx

uv

uv add rx

poetry

poetry add rx

Installing Rx

Before you install

Low friction installation with no runtime dependencies. Actively maintained with recent commits and a stable production release status, though the latest release was in 2021.

License in practice

MIT License permits commercial and private use with minimal restrictions, making it suitable for most projects without licensing concerns.

Quickstart

pip install rx

import rx
from rx import operators as ops

source = rx.of("Alpha", "Beta", "Gamma")
composed = source.pipe(
    ops.map(lambda s: len(s)),
    ops.filter(lambda i: i >= 5)
)
composed.subscribe(lambda value: print(value))

Requires Python 3.6 or above.

Verify before relying

  • Whether the 1937 days since release reflects a stable mature library or indicates stalled development relative to reactive programming ecosystem changes
  • Performance characteristics and scalability limits for high-throughput event streams
  • Compatibility with modern async/await patterns versus the observable-based API

Package facts

License MIT License (permissive)
Python support supports the current Python release (>=3.6.0)
Install friction low — pure-Python wheel
Runtime dependencies none
Maintenance actively maintained — 1,937 days since the last release
Last repo commit
First released
Downloads 4,712,467/month — #2,249 on PyPI (30-day window, as of 2026-08-14)
Known vulnerabilities none known (OSV.dev, checked 2026-08-14)

Evidence: Rx-3.2.0-py3-none-any.whl

Development Status :: 5 - Production/StableEnvironment :: Other EnvironmentIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseOperating System :: OS IndependentProgramming Language :: Python :: 3Programming Language :: Python :: 3.6Programming Language :: Python :: 3.7Programming Language :: Python :: Implementation :: CPythonTopic :: Software Development :: Libraries :: Python Modules

Tags

reactive programming pythonobservable sequencesasynchronous event handlingreactive extensionscomposable async streamsevent-driven programmingrxpy operators
reactive-programmingasync-eventsstream-processing

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