Monolith IDE

A self-hosted, browser-based IDE platform for CS students — inspired by Replit. Each user gets an isolated Docker container running VS Code in the browser, with no local setup required.

Built for BitCamp 2026

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What is this?

Repl.it shifted away from being a free, student-friendly web IDE toward a paid AI platform. Monolith IDE fills that gap by providing a locally/school-server-hosted, open-source alternative where students can write and run code directly in the browser.

How it works:

• Students sign in with Google
• They create a project (choosing Python, Java, or C++)
• The app spins up a dedicated Docker container running code-server (VS Code in the browser)
• When the browser tab is closed, the container automatically stops

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Features

• Google SSO — OAuth 2.0 with PKCE; no passwords to manage
• Isolated containers — each project runs in its own Docker container
• Multi-language support — Python 3, Java 17, C++ (g++) pre-installed
• Auto-stop on idle — WebSocket heartbeat stops the container when the user disconnects
• Project dashboard — create, start, stop, and delete projects from a single page
• Full VS Code — code-server provides the complete VS Code editor experience in-browser
• Self-hosted — deploy on your own server; no third-party cloud required

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Tech Stack

Layer	Technology
Backend	Python 3, FastAPI, Uvicorn
Templating	Jinja2
Frontend	Vanilla HTML / CSS / JavaScript
Auth	Google OAuth 2.0 (PKCE) + JWT (HS256)
Database	SQLite (sqlite3)
Containers	Docker (Docker-out-of-Docker pattern)
IDE	code-server
Proxy	Nginx
Orchestration	Docker Compose

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Prerequisites

• Python 3.11+
• Docker (running)
• A Google Cloud project with OAuth 2.0 credentials

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Setup

1. Clone the repository

git clone <repo-url>
cd replit_clone

2. Configure environment variables

cp .env.example .env

Edit .env and fill in the required values:

DOMAIN_URL=http://localhost:8000       # Your app's public URL
GOOGLE_CLIENT_ID=<your-client-id>
GOOGLE_CLIENT_SECRET=<your-client-secret>
JWT_SECRET=<random-secret-string>
DATABASE_URL=db/app.db                 # Use /app/data/data.db for Docker
CODE_SERVER_PASSWORD=                  # Optional password for code-server

In your Google Cloud Console, add <DOMAIN_URL>/api/googleAuth as an authorized redirect URI.

3. Build the code-server Docker image

cd infra
./build_image.sh
cd ..

This builds a Docker image (code-server-all) with Python 3, Java 17, and C++ pre-installed.

4. Run the development server

python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
./run.sh

The app will be available at http://localhost:8000.

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Production Deployment (Docker Compose)

# Configure .env first (set DOMAIN_URL to your public domain)

cd infra
./start.sh

This builds all Docker images and starts the app via Docker Compose. To also start the Nginx reverse proxy:

docker compose --profile production up -d

The app will be served on port 80.

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Project Structure

replit_clone/
├── app.py                      # FastAPI application & all routes
├── requirements.txt
├── run.sh                      # Dev server startup script
├── docker-compose.yml
├── .env.example
│
├── backend/
│   ├── auth.py                 # Google OAuth2 + PKCE + JWT
│   ├── db.py                   # SQLite database layer
│   └── schema.py               # Pydantic models
│
├── infra/
│   ├── Dockerfile.code-server  # User container image (Python + Java + C++ + code-server)
│   ├── Dockerfile.app          # App container image
│   ├── Dockerfile.proxy        # Nginx proxy image
│   ├── nginx.conf
│   ├── start.sh                # Full bootstrap script
│   ├── build_image.sh          # Build code-server image
│   ├── create_container.sh     # Create a user container
│   ├── start_container.sh      # Start a container
│   ├── stop_container.sh       # Stop a container
│   ├── delete_container.sh     # Remove a container
│   └── get_container_ip.sh     # Resolve container IP
│
├── static/                     # Frontend assets (CSS, JS)
├── templates/                  # Jinja2 HTML templates
│   ├── home.html               # Project dashboard
│   └── ide.html                # IDE view (iframe + WebSocket)
└── db/
    └── app.db                  # SQLite database (auto-created)

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API Reference

Method	Path	Description
GET	/	Login / landing page
GET	/home	Project dashboard (requires auth)
GET	/create	New project form (requires auth)
GET	/ide/{containerUuid}	IDE view for a container
GET	/api/googleRedirect	Start Google OAuth flow
GET	/api/googleAuth	Google OAuth callback
GET	/api/logout	Clear session and redirect to login
POST	/api/createContainer	Create a new project
POST	/api/startContainer/{containerUuid}	Start a container
POST	/api/stopContainer/{containerUuid}	Stop a container
POST	/api/deleteContainer/{containerUuid}	Delete a container
WS	/ws/{containerUuid}	Heartbeat WebSocket (auto-stops on disconnect)

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Database Schema

users

Column	Type	Notes
userId	INTEGER PK	Auto-increment
googleId	TEXT UNIQUE	Google OAuth subject ID
username	TEXT	Display name from Google

containers

Column	Type	Notes
containerId	INTEGER PK	Auto-increment
ownerId	INTEGER	FK → users.userId
containerUuid	TEXT UNIQUE	Used as Docker container name
name	TEXT	User-provided project name
language	TEXT	python, java, cpp, or vscode
status	TEXT	stopped or running
created_at	TIMESTAMP	Set by SQLite

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How Containers Work

Containers follow a Docker-out-of-Docker (DooD) pattern: the app container mounts /var/run/docker.sock and uses shell scripts to manage sibling containers on the host Docker daemon.

Container naming: replit-user-<containerUuid>

Each container runs code-server on port 8080. The Nginx proxy routes /container/<container_id>/<path> directly to the container's IP.

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License

Open source. See LICENSE for details.