Open-Source Alternatives to LeetCode

OnlineJudge is an automated platform for managing programming contests and evaluating submitted source code. It provides a complete online judge system that compiles, runs, and scores code submissions against predefined test cases within a sandboxed execution environment, ensuring the host system remains protected from untrusted user code. The platform supports both ACM-style penalty-based scoring and OI-style point-based scoring, with real-time leaderboard computation that dynamically updates participant rankings as submissions are judged. Contest organizers can create and schedule timed com

Hydro is an online judge platform and competitive programming management system. It provides the infrastructure to host programming contests, manage a library of programming problems, and evaluate code submissions against predefined test cases and time limits. The system utilizes a distributed code execution engine that scales judging tasks across multiple worker nodes to process high volumes of submissions. It is built as a modular judge framework, employing a plugin-based architecture that allows for the extension of system functionality without modifying the core source code. The platform

Javascript Playgrounds is a browser-based code execution engine designed for running untrusted JavaScript snippets and managing interactive playgrounds. The system isolates user-submitted code inside dedicated web workers to prevent main thread blocking and protect the host environment, while supporting dynamic module loading that fetches external libraries and third-party scripts on demand. The platform includes architectural tools for mobile device simulation, rendering application output inside configurable viewport wrappers with adjustable platform dimensions and status bar styling. Debug

Django User Accounts is a modular library for managing user registration, authentication, and profile workflows within Django applications. It provides a comprehensive framework for handling the full account lifecycle, including secure credential verification, password recovery, and email-based identity confirmation. The project distinguishes itself through a highly extensible architecture that allows developers to override default class-based views and implement custom hooks for unique user model requirements. It supports database-backed profile extensions, enabling the mapping of custom use

learn-gdscript is an interactive coding course and tutorial application designed to teach GDScript programming fundamentals. It functions as a game engine education tool that allows absolute beginners to study basic programming concepts, variables, and functions. The project utilizes a sandboxed environment for practicing code execution and provides in-engine interactive tutorials. It features guided walkthroughs that direct users through editor interfaces to help them locate and understand software tools. The curriculum covers game development logic, including the implementation of physics-

rusty_v8 is a Rust wrapper for the V8 JavaScript engine that allows for the embedding of a JavaScript runtime into native applications. It provides core components for managing engine bindings, memory allocation, sandboxed isolates, and the execution of WebAssembly modules. The project features a native host function bridge to map Rust functions to JavaScript objects and a dedicated memory allocator to manage thread-safe allocation and heap pressure. It includes a system for compiling and executing binary WebAssembly modules within the hosted native environment. The runtime covers capabiliti

Moodle is an open-source learning management system (LMS) that provides a complete platform for creating, delivering, and managing online courses, assessments, and learner progress. Its architecture combines database-driven content storage, a plugin-based modular extension system, hierarchical role-based access control, and a RESTful API layer, all built around multi-tenant course isolation that keeps each course's activities, users, and grading structures separate. The platform distinguishes itself through a comprehensive assessment and grading system that manages question banks, applies fle

The sandbox-sdk is a development kit designed for building secure, isolated execution environments on a global edge network. It provides a framework for creating ephemeral, containerized workspaces that allow developers to run untrusted code, manage build tasks, and host automated scripts without compromising host system security. By leveraging a serverless runtime, the platform enables the deployment of these environments directly at the network edge to ensure low-latency performance. The platform distinguishes itself by integrating language models with sandboxed execution, facilitating the

This project is an interactive programming curriculum and educational system designed to teach computer science and software engineering. It provides a structured set of courses and professional roadmaps focused on backend engineering, DevOps, and systems fundamentals. The platform is distinguished by an AI-powered coding tutor that provides Socratic guidance and contextual hints to help students find solutions independently. It features a browser-based code sandbox using WebAssembly to eliminate local environment setup, alongside automated test-based grading and spaced-repetition logic to re

Algorithm Visualizer is a web-based platform designed to bridge the gap between abstract code and concrete behavior by rendering logical operations into interactive animations. It functions as an educational environment where users can observe the step-by-step execution of computational logic, providing a visual browser for exploring how algorithms process data and change state in real time. The platform distinguishes itself through a custom instruction set that maps algorithmic operations to graphical primitives, ensuring consistent rendering across different programming languages. By utiliz