Nyx

Every Steam game,
on your terms.

Nyx adds games to your Steam library and keeps them on the latest build — straight from the store page, no clutter.

Download for Windows Standalone Using Millennium?
Free & auto-updating Windows 10 / 11 18 languages
What it does

Built to disappear into Steam

No second launcher, no separate library. Nyx works from inside Steam and gets out of the way.

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Add from the store page

Open any game's Steam store page and click “Add via Nyx.” It lands in your library like anything else.

↻

Always the current build

Nyx pulls the manifests for the build Steam is shipping today, so your games install and update to the real latest version.

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DLC included

Most games come with their DLC already entitled when you add them — nothing extra to hunt down.

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Native settings

A real Steam ▸ Nyx settings panel: pick libraries, toggle behavior, restart Steam — right where you'd expect it.

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Kill-switch

Turn Nyx off inside Steam in one click. Everything hides and Steam behaves exactly as it did before — fully reversible.

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Standalone or plugin

Run the standalone tray app, or drop in the Millennium plugin if you already use Millennium. Same core, your choice.

Download

Pick your version

Both are free and update themselves. Not sure? Take the standalone.

Recommended

Nyx Standalone

A small tray app that sets everything up for you. The simplest way to start — nothing else required.

Nyx.exe · 149 MB · Windows x64

Download Nyx

Millennium Plugin

For people already running Millennium. Installs the Nyx plugin into your existing setup.

Nyx-millennium-installer.exe · 146 MB

Get the plugin
How it works

Three steps, then it's just Steam

Install & launch

Run Nyx once. It sets up the unlock engine and adds a Nyx entry inside Steam — no manual file wrangling.

Add a game

Go to a game's store page and choose Add via Nyx. It fetches the current manifests and writes them where Steam looks.

Install & play

Restart Steam when prompted, then download and play like any owned game. Updates follow the live build.

FAQ

Questions people actually ask

Do I need to own the game?›
No. Nyx writes the manifest and depot files Steam needs, then Steam downloads the game from its own servers like any other title. That's the whole point.
Will my games stay up to date?›
Yes. Nyx tracks the build Steam is shipping right now and moves your added games to it, so they install and update to the current version instead of an old snapshot.
What about online games and Denuvo?›
Nyx installs the game. Playing a protected or online-only title can still need a separate fix — Nyx doesn't bundle those. Single-player games generally just work once installed.
Is it safe for my account?›
Nyx only writes local manifest and .lua files and deploys its unlock engine. It never logs into your account, never asks for your password, and never modifies game binaries. As with any tool of this kind, keep added multiplayer games off VAC-secured servers.
Why does antivirus flag the download?›
The build isn't code-signed (certificates are expensive) and it writes into Steam's folders, which heuristic scanners treat as suspicious. The plugin ships as plain Lua and JavaScript and the app is unobfuscated, so anyone can read exactly what it does.
Standalone or Millennium plugin?›
Take the Standalone if you're not sure — it sets everything up on its own. Pick the Millennium plugin only if you already run Millennium. Same core either way.
How do I remove a game, or Nyx itself?›
Remove a game from its store page ▸ Nyx icon ▸ Remove via Nyx. To remove Nyx, flip the kill-switch in Steam ▸ Nyx, or delete the engine files and the Nyx plugin folder. Your installed games stay put.
No black box

What Nyx touches on your PC

Nyx is readable — the plugin ships as plain Lua and JavaScript, and the app is unobfuscated. Here's exactly what changes, and how to undo it.

What it changes

  • ›Deploys the unlock engine into your Steam folder so added games can install.
  • ›Writes game .lua and .manifest files into Steam's config and depot cache.
  • ›Stores its own settings under %LocalAppData%\Nyx — never your Steam credentials.
  • ›That's it. No account login, no telemetry on what you play.

Removing things

  • ›A game: open its store page ▸ Nyx icon ▸ Remove via Nyx.
  • ›Nyx itself: flip the kill-switch in Steam ▸ Nyx to hide everything, or delete the engine files and the Nyx plugin folder.
  • ›Removing Nyx leaves your installed games where they are.