Welcome to Principia
Principia is a physics-based sandbox game. Build and play advanced contraptions, circuiting, minigames, puzzles, robot adventures and more. Open source, free and available for Windows, Linux, Android and more, download it today.
This site is the new community site for Principia. When you have installed Principia, enjoy the levels others have created, and register in order to upload your own levels and interact with the community.
Want to read more about Principia?
Also check out...
And the Official community site archive, an archive of old levels spanning from 2013 to 2018.
Apparatus player? Check out Principia for Apparatus Players on the Principia Wiki!
Featured levels
Latest news More
- 31 Dec 2025Principia in the web browser, and more...
- 6 Jul 2025Follow Principia on YouTube
- 14 Apr 2025New contest: Puzzling Puzzles
- 5 Apr 2025Principia 2025.04.05
- 22 Mar 2025Please help to test Principia
Top rated levels More
Latest custom levels More
Latest adventures More
Latest puzzles More
randomguy123 commented on Plasma: 18 hours ago
It is a really cool level, and it looks realisticrandomguy123 commented on The adventure of the walker: 1 day ago
It's ruined what the hellrandomguy123 commented on ♪Had to put the stick in the box♪: 1 day ago
I found the secret heart in the edge of the maprandomguy123 commented on Bearing: 2 days ago
Yeah that's trueROllerozxa commented on light sweep: 2 days ago
This level is very satisfying for some reason.ROllerozxa commented on Bored...: 2 days ago
quite funROllerozxa commented on Bearing: 2 days ago
Principia is probably not particularly well suited for creating ball bearings, too much pressure on the metal balls to make them able to roll around.randomguy123 commented on Bored...: 2 days ago
It looks like a sponge lol