🌐 Live Demo: https://450-ds.vercel.app

Track your progress through Love Babbar's 450 DSA problems — with platform sync, leaderboard, and more.

A full-stack Flask web app to help you track, manage, and share your DSA journey. Originally a React + LocalBase project, it's been completely rewritten in Python with MongoDB as the database.

• Topic-wise tracking — browse all 24 DSA topics and mark questions done
• Bookmarks — save questions for quick review
• Notes — write and save personal notes per question
• Search — full-text search with topic, difficulty, platform, and status filters
• OAuth login — sign in with GitHub or Google, or register with email/password
• Platform sync — connect LeetCode, GFG, GitHub, HackerRank, Coding Ninjas, AtCoder, and Codewars and pull your stats
• Profile dashboard — activity heatmap, rating chart, difficulty breakdown, badges
• Leaderboard — ranked by C-Score (composite score across all platforms)
• Public profiles — shareable profile cards
• Admin panel — manage users and content
• Export notes — download your notes as Markdown
• Docker support — run the whole app with one command

The platform sync feature currently supports:

• LeetCode
• GitHub
• GeeksforGeeks (GFG)
• HackerRank
• Coding Ninjas
• AtCoder
• Codewars

Provide the platform username or handle for supported platforms.

For Coding Ninjas, you may provide either:

• A profile ID
• A full Coding Ninjas profile URL

Platform sync requests are rate limited to avoid excessive requests to external services.

After a sync attempt, users must wait 10 minutes before starting another sync. If a sync is attempted before the cooldown expires, the remaining wait time is returned in the response.

Each platform reports its sync result independently:

Platform sync operations are processed independently.

• If at least one platform syncs successfully, the overall request is considered successful.
• If some platforms succeed and others fail, the response includes partial_success: true.
• If all requested platforms fail, the sync request is considered unsuccessful.
• If no platforms are provided, no sync attempt is performed.

Common causes of sync failures include:

• Invalid username or handle
• Incorrect Coding Ninjas profile ID or URL
• No solved problems found on the platform
• External API rate limits
• Temporary platform outages
• External service errors

If a platform fails to sync, verify the supplied username or profile information and try again later.

Note: If you recently changed your username on a platform, allow some time for the change to propagate before syncing again.

1. Clone and set up environment

git clone https://github.com/mohitkumhar/450-dsa.git
cd 450-dsa
python -m venv venv

# Windows
venv\Scripts\activate

# macOS/Linux
source venv/bin/activate

pip install -r requirements.txt

# For development, linting, and tests
pip install -r requirements-dev.txt

2. Configure environment variables

cp .env.example .env   # macOS/Linux
copy .env.example .env  # Windows

Edit .env and fill in your values:

# REQUIRED - generate your own first:
# python -c "import secrets; print(secrets.token_hex(32))"
SECRET_KEY=replace-this-with-a-real-secret

# MongoDB — use Atlas (free) or local
MONGO_URI=mongodb+srv://<user>:<password>@cluster.mongodb.net/dsa_tracker

# GitHub OAuth (optional)
GITHUB_CLIENT_ID=your-github-client-id
GITHUB_CLIENT_SECRET=your-github-client-secret

# Google OAuth (optional)
GOOGLE_CLIENT_ID=your-google-client-id
GOOGLE_CLIENT_SECRET=your-google-client-secret

# Cloudinary — for profile photo uploads (optional)
CLOUDINARY_CLOUD_NAME=your-cloud-name
CLOUDINARY_API_KEY=your-api-key
CLOUDINARY_API_SECRET=your-api-secret

The app warns and generates a temporary SECRET_KEY if the variable is missing or still set to an insecure placeholder. Set a real generated secret in deployed environments so user sessions persist across restarts. If a secret was ever committed or shared, rotate it before running the app again.

3. Run

python run.py

Open http://localhost:5000 in your browser. The app seeds all 450+ questions from data.json on first run.

git clone https://github.com/mohitkumhar/450-dsa.git
cd 450-dsa
docker compose up

Open http://localhost:5000.

450-dsa/
├── app/
│   ├── __init__.py          # App factory
│   ├── extensions.py        # Shared Flask extensions (db, bcrypt, limiter...)
│   ├── utils.py             # Helpers, search logic, leaderboard scoring
│   ├── auth/                # Login, register, OAuth (GitHub, Google)
│   ├── tracker/             # Topics, questions, bookmarks, notes
│   ├── profile/             # Profile page, platform sync, photo upload
│   ├── search/              # Search API with filters
│   ├── leaderboard/         # Leaderboard routes and API
│   ├── admin/               # Admin dashboard
│   ├── public/              # Public profile pages
│   ├── faq/                 # FAQ page
│   └── platforms/
│       └── fetchers.py      # LeetCode, GFG, GitHub, HackerRank, Coding Ninjas fetchers
├── templates/               # Jinja2 HTML templates
├── static/                  # CSS and JS assets
├── tests/                   # Pytest test suite
├── data.json                # All 450+ DSA questions
├── run.py                   # App entry point
├── requirements.txt         # Python dependencies
├── requirements-dev.txt     # Dev/test dependencies
├── .env.example             # Environment variable template
├── Dockerfile
└── docker-compose.yml

The app uses MongoDB (via Flask-PyMongo). There is no SQLite or SQLAlchemy — those were part of an earlier version.

Collections:

• user — user accounts, progress, platform usernames, external stats
• topic — DSA topic names and ordering
• question — all 450+ problems with URLs

MongoDB is accessed through app.extensions.db (a LocalProxy to mongo.db). All indexes are created on startup in app/__init__.py.

You can use MongoDB Atlas (free M0 tier) or a local MongoDB instance.

pip install -r requirements-dev.txt
pytest

• DSA problem set curated by Love Babbar — 450 DSA Cracker Sheet
• Flask conversion and ongoing development by the open-source community

PRs are welcome! Please read CONTRIBUTING.md before opening one.

• Enable Redis cache invalidation on list updates.