An online judge is an online system to test programs in programming contests. They are also used to practice for such contests like ICPC. The system can compile and execute your code, and test your code with pre-constructed data. Submitted code may be run with restrictions, including time limit, memory limit, security restriction, and so on. The output of the code will be captured by the system, and compared with the standard output. The system will then return the result.

Hydro - Next generation high performance online-judge platform - 新一代高效强大的信息学在线测评系统 (a.k.a. vj5)

• UpdatedDec 17, 2025
• TypeScript

Robust, fast, scalable, and sandboxed open-source online code execution system for humans and AI.

• UpdatedDec 15, 2025
• HTML

Popular Simple Open Source Online Judge based on PHP/C++/MySQL/Linux for ACM/ICPC and NOIP training, with easy installation. 简单实用的开源OJ系统

• UpdatedDec 18, 2025
• JavaScript

A modern open-source online judge and contest platform system.

• UpdatedDec 14, 2025
• Python

✨ Simple, free and open-source online code editor.

• UpdatedNov 9, 2025
• JavaScript

Judging backend server for the DMOJ online judge.

• UpdatedSep 4, 2025
• Python

⚡ The most advanced open-source automatic algorithm online judge system | 南京邮电大学开源 Online Judge | QQ群：668108264

• UpdatedMar 26, 2024
• PHP

The problem data (Test case generator, judge's solution, task, ...) of Library Checker

• UpdatedNov 23, 2025
• C++

A cross-platform online judge system based on Spring MVC framework and ActiveMQ.

• UpdatedSep 16, 2025
• Java

Sandbox service built on Linux container technologies with simple REST and gRPC API

• UpdatedDec 18, 2025
• Go

Universal Online Judge

• UpdatedJul 13, 2025
• JavaScript

The online judge service with millions of submissions, since 2005.

• UpdatedJan 1, 2024
• Python

PAT OJ exercises in C language 浙江大学PAT纯C语言题解。

• UpdatedJun 1, 2023
• C

浙江大学PAT题解https://pintia.cn

• UpdatedMay 4, 2025
• C++

Jiangnan Online Judge

• UpdatedJan 8, 2024
• JavaScript

An open source online judge system base on Django REST framework and Vue.js !

• UpdatedMar 4, 2024
• Vue

A full-stack online coding platform powered by Spring Cloud microservices and a Vue 3 frontend, offering scalable, secure, and interactive coding challenges.

• UpdatedOct 29, 2025
• Java

Solutions collection of LeetCode submissions in JavaScript & TypeScript (LeetCode 解题集之 JavaScript & TypeScript 版)

• UpdatedJan 11, 2024
• JavaScript

LeetCode 算法解答

• UpdatedNov 14, 2021
• C++

A modern open-source online judge and contest platform system.

• UpdatedDec 11, 2025
• Python