DevForces

A competitive coding platform where developers build backend systems and battle-test them against hidden test suites — all inside isolated Docker containers.

Built for large-scale online cohorts, DevForces lets admins create contests, and participants submit code that gets executed and evaluated in real-time with live-streamed logs and Codeforces-style leaderboards.

Tech Stack

Layer	Tech
Frontend	Next.js, React, Tailwind CSS, Jotai
Backend	Express, Prisma, PostgreSQL, Redis
Worker	Dockerode, Vitest (test runner)
Infra	Docker Compose, AWS S3, SSE
Monorepo	Turborepo, pnpm workspaces

Features

• Contest System — Create and manage timed coding contests with multiple challenges
• Isolated Execution — Every submission spins up fresh Docker containers, keeping test cases hidden
• Real-time Logs — Live-streamed test execution output via Server-Sent Events
• Codeforces-style Scoring — Ranking based on tests passed, retry penalties, and submission time
• Live Leaderboard — Real-time standings updated as submissions are evaluated
• Notion Integration — Problem statements rendered directly from Notion pages
• Drag & Drop Submissions — Upload project files from the browser, auto-zipped and sent to S3

Architecture

Browser → Next.js Frontend
              ↓
         Express API → PostgreSQL (data) + Redis (queue & pub/sub)
              ↓
         Worker → Downloads from S3 → Builds & runs in Docker → Streams results back via Redis

Project Structure

apps/
  web/        → Next.js frontend
  backend/    → Express API server
  worker/     → Submission processor (Docker-based)
packages/
  db/         → Prisma schema & client
  common/     → Shared types & validation (Zod)
  email/      → Email service (Resend)
  ui/         → Shared UI components
docker/       → Dockerfiles & docker-compose configs

Getting Started

Prerequisites

• Node.js >= 18
• Docker & Docker Compose
• pnpm 9+

Setup

# Install dependencies
pnpm install

# Run database migrations
pnpm run db:migrate

# Start all services
docker compose -f docker/docker-compose.yml up

The app will be available at http://localhost:3000 with the API on port 3001.

Development (without Docker)

pnpm run start:webdev     # Frontend on :3000
pnpm run start:backend    # API on :3001
cd apps/worker && pnpm dev # Worker

Make sure PostgreSQL and Redis are running locally or update .env accordingly.

How It Works

1. Admin creates a contest with challenges (Notion doc + Vitest test file + GitHub template)
2. Participant opens the Arena, reads the problem, and builds their solution locally
3. Participant drags & drops their project files into the browser
4. Files are zipped, uploaded to S3, and queued for processing via Redis
5. Worker pulls the submission, builds it in Docker, runs the test suite
6. Logs stream back in real-time; results update the leaderboard instantly

License

MIT