Open source by industry / Education
Hydro
An online judge for programming: students submit code and it is graded automatically.
- Can you use it commercially?
- With conditions
Mostly AGPL-3.0 with additional terms: the "Powered by Hydro" footer and link must stay, and modified source must also be released under AGPL-3.0. If you need closed source, the README says to contact the authors for a separate license.
- Is it still maintained?
- Active
Last push on 2026-10-09. The repository is not archived.
- How hard is it to deploy?
- Easy
A one-command install script. The README recommends Debian 12 and supports x86_64 and arm64. The script does not support CentOS and warns if it detects the BT panel; use a clean system.
- What does it cost?
- Low
The software is free and the README says it runs on a Raspberry Pi. If you would rather not host it, there is a free hosted version. Server requirements were not found here.
- What to watch out for
- The install script has telemetry
The install script states up front that it includes system telemetry about the operating system and platform; turning it off means reading the source. Importing problems from Luogu requires a separate license from Luogu.
Based on license texts, commit history and official deployment docs. I have not deployed each one myself. Last checked: .
Your industry is not here?
Tell me the industry and what you need solved. I will look at it next.