Codezy is a feature-rich, high-performance competitive programming and interactive learning platform. It allows users to write, compile, run, and submit code against test cases in real-time, generate fresh situational coding problems using AI, upload and watch video editorials, and participate in competitive coding contests with real-time leaderboards and user-solving broadcasts.
The system is built as a split client-server architecture utilizing MongoDB for storage, Redis for performant token blacklist management & database caching, Socket.io for real-time broadcasts, Google Gemini 2.5 Pro for AI content generation, and a dedicated Judge0 VPS instances for isolated code execution.
graph TD
Client[React + Vite Frontend] <-->|HTTP / WebSockets| Server[Node.js + Express Backend]
Server <--> Database[(MongoDB)]
Server <--> Cache[(Redis Client)]
Server -->|Generate Problems| GeminiAPI[Google Gemini 2.5 Pro]
Server -->|Compile & Run Batch Code| Judge0[Judge0 VPS Compiler]
Client -->|Direct Secure Video Upload| Cloudinary[Cloudinary Media Storage]
Server -->|Verify Video Signatures| Cloudinary
- Interactive Workspace: Built with ProblemPage.jsx featuring clean split panes and resizable layouts.
- Modern Editor: Employs Monaco Editor (
@monaco-editor/react) and CodeMirror with syntax highlighting, autocomplete, and indentation rules. - Multi-Language Support: Supports coding in JavaScript, C++, and Java with pre-populated starter function templates.
- Judge0 Sandbox Sandbox: Code execution runs securely inside isolated Judge0 environments.
- Run & Submit Modes:
- Run Code: Compiles and validates logic against visible test cases.
- Submit Code: Evaluates code against hidden edge cases and saves performance metrics (runtime, memory usage).
- Driver Code Wrapper: Automatically wraps user-implemented function methods inside standardized header and footer boilerplate inputs handled by userSubmission.js.
- Automatic Creation: Harnesses Gemini 2.5 Pro in generateProblem.js to dynamically compile situation-based DSA questions.
- Instant Insertion: Users select difficulty and topic (
Array,Linked List,Graph,DP), and the backend inserts a structured problem containing starter codes, driver setup, and test cases directly into the judge database. - UI Controls: Driven by the custom ChatAi.jsx component.
- Contest Engine: Enables admins to schedule coding contests via contest.js and createContest.js.
- Live Timers: Provides active count-downs and synchronized starts.
- Interactive Leaderboard: Automatically ranks participants in real-time based on test cases passed, runtime speed, and points accrued.
- Live Broadcast Toasts: Instantly notifies active users when a peer successfully solves a problem using Socket.io server listeners in index.js and triggers client-side toasts in App.jsx.
- Interactive Comments: Threaded discussion logs per coding problem.
- Video Editorial Hub: Admins and creators upload walkthrough videos via Cloudinary. The backend handles secure api signature generation and resource verification under videoSection.js.
- Peer Bug Reporting: Directly integrated issue reporting tool using EmailJS.
- Dual Auth Strategies: Email/Password registrations alongside Passport Google OAuth 2.0.
- Redis JWT Blocklist: Upon logout, JWT tokens are blocklisted in Redis with automatic TTL expiry to prevent unauthorized reuse.
- Special AI Rate-Limiting: Tracked via JWT-signed session limits (enforced to 2 uses per session via featureMiddleware.js).
- Build tool & Library: Vite + React (v19)
- Styling: Tailwind CSS (v4) + DaisyUI
- State Management: Redux Toolkit (auth state persistence)
- Real-time connectivity: Socket.io-client
- Interactive components: Monaco Editor, CodeMirror, React Resizable Panels, Chart.js, React Confetti, Lucide React icons, and GSAP.
- Server Framework: Node.js + Express (v5)
- Database: MongoDB (Mongoose Object Modeling)
- Caching & Security Layer: Redis
- Third Party Integrations:
- Google Gemini API (
@google/genai) for problem synthesis. - Judge0 batch API for code compilation and execution.
- Cloudinary API for solution video assets storage.
- Passport.js & JSONWebToken for authorization.
- Google Gemini API (
├── backend/
│ ├── src/
│ │ ├── config/ # DB, Passport, and Redis client setups
│ │ ├── controllers/ # Authentication, Contest, and Code evaluation handlers
│ │ ├── middleware/ # Rate-limiting, Admin check, and User authentication
│ │ ├── models/ # MongoDB Mongoose schemas
│ │ ├── routes/ # Express route endpoints mapping controllers
│ │ ├── utils/ # Base64 converters and Judge0 batch execution helper
│ │ └── index.js # Backend server gateway and WebSocket manager
│ ├── .env.example
│ └── package.json
├── frontend/
│ ├── public/
│ ├── src/
│ │ ├── assets/
│ │ ├── components/ # Modular UI components (ChatAi, Comment, Profile, etc.)
│ │ ├── pages/ # Core layout views (IDE Sandbox, Leaderboard, Contests)
│ │ ├── socket/ # Socket.io connection instantiator
│ │ ├── store/ # Redux store config
│ │ ├── authSlice.js # User authentication actions & slice
│ │ └── App.jsx # Route configurations and socket dispatch hooks
│ ├── .env.example
│ └── package.json
└── README.md # Project documentation
To configure the application, create a .env file in both backend and frontend directories using the reference templates below:
NODE_ENV=development
PORT=3000
# Databases
DB_CONNECT_STRING=your_mongodb_connection_url
REDIS_PASS=your_redis_password
# Authentication Secrets
JWT_KEY=your_secure_jwt_signing_key
GOOGLE_CLIENT_ID=your_google_oauth_client_id
GOOGLE_CLIENT_SECRET=your_google_oauth_client_secret
GOOGLE_CALLBACK_URL=http://localhost:3000/user/auth/google/callback
CLIENT_URL=http://localhost:5173
# AI & Third Party APIs
GEMINI_KEY=your_google_gemini_api_key
CLOUDINARY_CLOUD_NAME=your_cloudinary_cloud_name
CLOUDINARY_API_KEY=your_cloudinary_api_key
CLOUDINARY_API_SECRET=your_cloudinary_api_secret
# Code Judge Compilers
JUDGE0_API_KEY=your_judge0_api_key
JUDGE0_VPS_URL=http://your_vps_ip_address:2358# EmailJS parameters for Bug Report Feature
VITE_EMAILJS_PUBLIC_KEY=your_emailjs_public_key
VITE_EMAILJS_SERVICE_ID=your_emailjs_service_id
VITE_EMAILJS_TEMPLATE_ID=your_emailjs_template_idManaged in userAuth.js.
POST /user/register: Registers a new user account.POST /user/login: Logs in using credentials.POST /user/logout: Standard credentials logout (blocklists token in Redis).GET /user/auth/google: Initiates Google OAuth sequence.GET /user/profile: Fetches current logged-in profile metrics.POST /user/comment/:id: Submits discussion comment on a problem.
Managed in problemCreator.js.
POST /problem/create: Submits and creates a coding problem (Admin & User).PUT /problem/update/:id: Edits problem details and test cases (Admin Only).DELETE /problem/delete/:id: Removes problem from the catalog (Admin Only).GET /problem/problemById/:id: Retrieves detailed problem constraints and templates.GET /problem/getAllProblem: Fetches list of all problems (cached in Redis).
Managed in submit.js.
POST /submission/run/:id: Evaluates custom code against visible test cases.POST /submission/submit/:id: Grades code against hidden test cases. Saves submission status.
Managed in generateAi.js.
POST /ai/generate-problem: Commands Gemini to draft complete problem JSON details.POST /ai/sanitize-problem: Formatting checker (requires user authentication).
Managed in videoCreator.js.
GET /video/signature/:problemId: Generates upload hash parameters for direct Cloudinary uploads.POST /video/saveMetadata: Saves uploaded video Cloudinary public-id and thumbnail URL.DELETE /video/delete/:problemId: Discards solution walkthroughs (both DB & Cloudinary storage).
Managed in contest.js.
POST /contest/create: Creates a scheduled contest (Admin Only).GET /contest/all: Lists all upcoming and live contests.GET /contest/getContest/:id: Opens active contest workspace and details.POST /contest/submit/:id: Submits contest problem code.GET /contest/leaderboard/:id: Compiles sorted standings of active contest.
erDiagram
USER ||--o{ SUBMISSION : creates
USER ||--o{ CONTEST : hosts
USER ||--o{ COMMENT : posts
PROBLEM ||--o{ SUBMISSION : validates
PROBLEM ||--o{ COMMENT : discussed-on
PROBLEM ||--o| SOLUTIONVIDEO : explains
CONTEST ||--o{ SUBMISSION : evaluates
USER {
ObjectId id
String firstName
String lastName
String emailId
String password
String role
ObjectIdArray problemSolved
}
PROBLEM {
ObjectId id
String title
String description
String difficulty
String problemType
String tags
ObjectArray visibleTestCases
ObjectArray hiddenTestCases
ObjectArray startCode
ObjectArray driverCode
ObjectArray referenceSolution
ObjectId problemCreator
}
SUBMISSION {
ObjectId id
ObjectId userId
ObjectId problemId
String code
String language
String status
Int testCasesPassed
Int testCasesTotal
Float runtime
Float memory
}
CONTEST {
ObjectId id
String title
String description
Date startTime
Date endTime
String status
ObjectArray visibleTestCases
ObjectArray hiddenTestCases
ObjectArray startCode
ObjectArray referenceSolution
}
Follow these steps to run Codezy on your local development machine:
- Node.js (v18 or higher recommended)
- MongoDB instance (Local or Atlas)
- Redis (Local instance or Cloud account)
- Google Gemini API Key and Cloudinary Credentials
-
Clone the repository
git clone <repository_url> cd final_code
-
Backend Setup
cd backend npm install # Create a .env file and paste variables from the reference above npm run dev
The backend server should start listening on
http://localhost:3000. -
Frontend Setup
cd ../frontend npm install # Create a .env file and paste variables from the reference above npm run dev
The frontend developer portal should launch on
http://localhost:5173. -
Verify Installations
- Visit
http://localhost:5173on your browser to sign up / log in. - Access the backend status check endpoint at
http://localhost:3000/healthCheckto confirm database connectivity.
- Visit