Principia

F-Droid Open Source | Puzzle Game

12 Downloads 20 Views v2026.1 28.84 MB 4.1+

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(28.84 MB)

Editor's Overview

Principia is a puzzle game application developed by F-Droid Open Source, packaged as a single Android APK of version 2026.1 weighing in at 28.84 MB. The package targets Android 4.1+ and above. Below you'll find the publisher's own description, a quick spec sheet, and a short buyer-beware checklist so you know exactly what you're installing before tapping download.

Install Checklist

Only download through the button on this page — never from third-party mirrors or shortened links, which are the most common way malware spreads.
File size is a light 28.84 MB, so it installs quickly even on modest connections.
This build is signed by "F-Droid Open Source" — always verify the developer name matches what's listed on the app's official store page before installing an update.
After install, Android may prompt you to allow "Install from unknown sources" — approve only this one install, then revoke the permission in Settings > Apps > Special access.
We link directly to the APK file or the publisher's repository; we do not modify the binary. Always run a virus scan after any sideloaded install.

About this app

Principia is a physics-based sandbox building game. Build and play advanced contraptions, circuiting, minigames, robot adventures and more.

The sandbox contains 200+ different objects ranging from basic wooden building blocks to circuitry, electrical and mechanical components, small robots you can control and fight against, and a LuaScript object featuring Lua scripting that can interact with the world. Build a controllable car, a calculator or make your own game with circuitry or in Lua.

The Principia community site contains tens of thousands of creative levels made by players like you, from impressive contraptions to amusing games all for you to browse through and play. If something really peaks your interest, open the level in the sandbox to see how it ticks. What will you create in the sandbox?

Principia started out as a paid proprietary game developed during 2013-2014 before being abandoned due to financial issues. Now the game is an open source project since 2022 developed by the same community who fell in love with it back in the day, free for anyone to play well into the future.

In addition to being available on Android, Principia is also available on Linux, Windows as well as experimental ports to other platforms.

(By default Principia makes connections to the main community site at principia-web.se. You can change or disable this by creating a file called community_host.txt in the app's scoped storage containing a domain name. If you have the main community site disabled you can still play levels by going via your web browser.)

Details

Version	v2026.1
Size	28.84 MB
Developer	F-Droid Open Source
Category	Puzzle Game
Package	com.bithack.principia
Android	4.1+
Last Updated	Oct 29, 2026
Downloads	12

Frequently Asked Questions

Is Principia free to download?
Yes. The APK file linked from this page is free. The developer may offer in-app purchases once installed, but obtaining the installer itself costs nothing.

What Android version does Principia require?
Android 4.1+ or newer. Installing on older devices may cause crashes or refuse to install.

Is Principia safe to install?
We link to the exact APK published by F-Droid Open Source. We do not modify the file. Still, as with any sideloaded app, scan it with a reputable antivirus before opening it, and only grant permissions the app genuinely needs.

How do I update Principia?
Install the newer version on top of the old one — Android will keep your data. If the signature differs, uninstall first (you may lose local progress).

Why is the app not installing?
Common causes: not enough storage, an older Android version than 4.1+, or a conflicting build already installed. Free up space, check your OS version, and uninstall any previous copy before retrying.

How to Download & Install Principia

Tap the Download APK button above and save the file to your device.
Open your device Settings → Security (or Apps → Special access → Install unknown apps) and allow your file manager or browser to install unknown apps for this one file only.
Open the downloaded com.bithack.principia.apk file from your Downloads folder.
Tap Install and wait for Android to finish.
Open «Principia» by F-Droid Open Source and grant only the permissions it actually needs.
Revoke the "unknown sources" permission once you are done installing.

Note: this page hosts or links to the installer only. The application name, icon and description are provided for identification. All trademarks belong to their respective owners.