Flox is a software environment platform for engineering teams that delivers cryptographically pinned, reproducible environments, identical from a developer's laptop through CI to production. Built on Nix, with Nix knowledge optional, Flox eliminates environment drift, strengthens software supply chain security, and gives AI coding agents a deterministic foundation to build on.
It's more than a package manager: where traditional package managers work on a single machine, Flox manages the lifecycle of packages and environments across your entire organization.
- Declarative. One file describes every tool, environment variable, and service your project needs.
- Reproducible. The same definition produces the same environment on any supported system.
- Composable. Layer environments per project, per team, and per pipeline.
Who Flox is for
- Platform & DevX teams standardizing toolchains across the org, cutting onboarding from days to minutes, and extending golden base environments while keeping standards intact, without forcing everyone to learn Nix.
- Security and AppSec teams who need SBOMs, fast CVE remediation, dependency provenance, and reproducible builds across every service.
- Developers who want one reproducible, per-project environment for any stack on macOS, Linux, or Windows (WSL2). More like a virtual environment than a container or VM, with nothing to spin up before you code.
- AI coding agents that need a deterministic, reproducible environment to build and run generated code the same way on every run.
Why Flox?
- Reproducible by construction. Every environment is defined in a declarative manifest and locked to cryptographically pinned, content-hashed inputs. The same lockfile resolves to the same packages on every supported system, so environments stay identical across machines. No drift.
- One definition, laptop to production. The same environment runs on a developer's laptop, in an AI agent's sandbox, through CI, and in production. Tutorial.
- 120,000+ packages. Pull from Nixpkgs, the largest open source package repository, updated continuously.
- Build and package your own software. Build custom software from source into reproducible packages and publish them for your whole team, alongside everything from Nixpkgs. Learn more.
- A software supply chain you can defend. SBOMs, automated vulnerability and CVE patching, software composition analysis (SCA), and clean, auditable builds fall out of reproducibility instead of being bolted on afterward. Learn more.
Install
The Flox CLI installs natively on macOS, Linux, and Windows (WSL2):
- macOS:
brew install flox, or the .pkg installer
- Linux:
.deb (Debian/Ubuntu) or .rpm (Fedora/RHEL) packages
- Windows: via WSL2, using the Linux packages
See the installation guide for step-by-step instructions on every platform.
Quick Start
$ flox init # Create an environment in your project
⚡︎ Created environment 'my-project' (aarch64-darwin)
$ flox install python3 nodejs # Install packages (any combination of tools)
✔ 'python3', 'nodejs' installed to environment 'my-project'
$ flox activate # Enter the environment
flox [my-project] $ python3 --version
Python 3.13.13
flox [my-project] $ node --version
v24.15.0
flox [my-project] $ exit # Leave, and the tools are gone
$ python3 --version
python3: command not found
📖 New here? Follow Flox in 5 minutes to walk through it step by step.
That's the core idea: tools appear when you activate, and disappear when you leave. Each environment is isolated, so projects never collide and your system stays clean. And because it lives in a file, the same environment reproduces everywhere: laptop, CI, and production.
⭐ If Flox looks useful, give us a star. It helps others discover the project. ⭐
This is the beginning of the README. Read the rest at the original. Read the full README ↗
