LeetCode Clone w/ Docker-based Code Judging System

About this project

LeetCode-like coding challenge platform with a code submission testing sandbox built around Docker. Called DeceitCode because it has anti-LLM prompts all over it that would hopefully reduce cheating with LLM-based tools. The frontend (React + Monaco) provides a workspace and submit/run flows. The backend (Node + Express + TypeScript + MongoDB) serves problems, auth, and judges submissions via a remote sandbox service (Go, Docker, gVisor).

This project uses a service from my separate repo for the RemoteCodeSandbox. See: https://github.com/joshL1215/RemoteCodeSandbox

System Design

Problem Database

Interactive frontend with Monaco code editor

Code judging with custom code execution sandbox

Local setup

Prerequisites

• Node.js 22.x (or compatible) and npm
• Docker & docker-compose (recommended for Mongo)
• Git

How to run

1. Clone repository

   git clone <this-repo-url>
   cd DeceitCode
   

2. Start MongoDB

   • With Docker Compose (my recommendation):

     docker compose up -d
     

3. Run RemoteCodeSandbox

   git clone https://github.com/joshL1215/RemoteCodeSandbox
   cd RemoteCodeSandbox
   go run cmd/api/main.go
   

4. Configure server environment

   • Create server/.env with at minimum:
     • MONGO_URI (e.g. mongodb://localhost:27017/deceitcode)
     • SANDBOX_URL (pointing to RemoteCodeSandbox instance that you ran)
     • APP_ORIGIN (frontend origin)
     • JWT_SECRET
     • JWT_REFRESH_SECRET
   • Example:

     MONGO_URI=mongodb://localhost:27017/deceitcode
     SANDBOX_URL=http://localhost:3000/sandbox
     APP_ORIGIN=http://localhost:5173
     JWT_SECRET=your_jwt_secret
     JWT_REFRESH_SECRET=your_refresh_secret
     

5. Install & run backend

   cd server
   npm ci
   npm run dev
   

   • Server defaults to http://localhost:5000 (see server/src/server.ts)

6. Seed problems (optional)

   cd server
   npm run seed
   

7. Install & run frontend

   cd client
   npm ci
   npm run dev
   

   • Open the Vite URL printed in terminal (default: http://localhost:5173). The frontend will call the backend at the server origin configured (APP_ORIGIN/CORS).