# reactos/reactos

A free Windows-compatible Operating System

Repository: https://github.com/reactos/reactos
Canonical: https://ross.abutalabs.com/products/reactos
Homepage: https://reactos.org/
Language: C
License: GPL-2.0
License Family: copyleft
Topics: operating-system, c, kernel, os, osdev, x86, windows, win32, win32api, drivers, gpl, reactos, hacktoberfest
Last push: 2026-08-26T17:46:14+00:00

## Health v2 (maintenance only)
Score: 67/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 8, longevity 100
- inputs: {"age_days": 3256, "days_push": 7, "days_rel": 530, "gap_med": null, "n_releases_24m": 1}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 17967, forks 2191 (observed 2026-08-28T04:11:20.610524+00:00)

## What it is
ReactOS is a free, open-source operating system written from scratch that is binary-compatible with applications and drivers written for the Microsoft Windows NT family (NT4 through Windows 7 era). It is currently in Alpha quality and under heavy development, targeting Windows Server 2003 compatibility with an eye toward newer NT releases.

## Use cases
- run Windows applications without a Windows license
- run Windows drivers on an open-source OS
- study operating system and kernel development
- test software in a Windows-compatible environment
- privacy-focused alternative to Windows telemetry
- contribute to an open-source Windows reimplementation

## When to choose
- you need a free, open-source OS that can run Windows apps and drivers
- you want to learn or contribute to OS/kernel development
- you need a lightweight Windows-like environment for VMs or old hardware
- you care about privacy and want an OS with no telemetry

## When to avoid
- you need a production-ready, stable daily-driver OS
- you require compatibility with modern Windows 10/11 software
- you cannot tolerate data corruption or frequent bugs
- you just need to run Windows apps occasionally - a VM with real Windows or Wine may be more practical

## Facets
- artifact type: application
- maturity: experimental
- function: security, privacy
- domain: operating-systems, windows, self-hosted, privacy
- platform: windows, cross-platform
- tags: osdev, win32, windows-compatible, kernel, drivers, open-source-os, operating-system, x86

## Member repositories
- reactos/reactos (main) score 67

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:11:20.610524+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:02:12.416054+00:00, confidence not recorded.
  - readme: https://github.com/reactos/reactos (fetched 2026-08-28T04:11:20.610524+00:00, sha c1bcc046df0b)
  - homepage: https://reactos.org/ (fetched 2026-08-29T08:00:20.576679+00:00, sha 7d74fc0c3af3)
  - site_page: https://reactos.org/faq (fetched 2026-08-29T08:00:20.585966+00:00, sha 2ef379ae9fdc)
- Data as of 2026-08-30T08:39:29.467469+00:00.