Full-stack · Advanced · 2–3 weeks
Real-time Collaborative Whiteboard
A multiplayer canvas where several people draw, add sticky notes, and see each other's cursors live, with edits that never conflict.
- React
- TypeScript
- Yjs (CRDT)
- WebSockets
- Node.js
- PostgreSQL
Features
- Shapes, freehand drawing, and sticky notes
- Live cursors and presence indicators
- Conflict-free merging of simultaneous edits using CRDTs
- Shareable boards with view-only and edit links
- Persistent boards with version history
Bonus: Offline editing that merges cleanly with everyone else's changes when you reconnect.
Full-stack · Advanced · 2–3 weeks
Live Coding Interview Room
Create a room, share a link, and code together in a shared editor. Code runs in sandboxed containers and both people see the output.
- Next.js
- Monaco Editor
- WebSockets
- Docker
- Redis
Features
- Shared editor with synced cursors and selections
- Run Python, JavaScript, or C++ in isolated containers with CPU, memory, and time limits
- Private notes panel only the interviewer can see
- Session playback of the whole interview
- Rooms that expire and clean up automatically
Bonus: Hidden test cases that grade the candidate's solution automatically and show a pass/fail report.
Full-stack · Intermediate · 2 weeks
Uptime Monitor & Public Status Page
Monitors websites and APIs every minute, detects outages, opens incidents, and publishes a clean public status page with uptime history.
- Next.js
- TypeScript
- PostgreSQL
- Node.js worker
- Email or Discord webhooks
Features
- HTTP, TCP, and keyword checks run on a schedule by a worker
- Incident detection that confirms with retries to avoid false alarms
- 90-day uptime bars and response-time charts
- Email and Discord alerts when something goes down
- Admin page for posting incident updates
Bonus: Checks from two regions that only open an incident when both agree the service is down.
Security · Intermediate · 1–2 weeks
Git Secrets Scanner & GitHub Action
A CLI and GitHub Action that scans repositories, including full commit history, for leaked API keys, passwords, and private keys.
- Go
- Regex + entropy analysis
- GitHub Actions
- SARIF
Features
- Pattern and entropy-based secret detection
- Fast scanning of the full Git history
- Allowlist file to suppress false positives
- SARIF output that shows up in GitHub code scanning
- Pre-commit hook mode that blocks leaks before they happen
Bonus: A seeded test corpus that reports precision and recall, compared against an existing open-source scanner.
Security · Intermediate · 1–2 weeks
SSH Honeypot with Attack Dashboard
A fake SSH server on a cheap cloud VM that records the logins and commands real attackers try, shown on a live dashboard.
- Python (asyncssh) or Go
- Docker
- PostgreSQL
- Grafana
- GeoLite2
Features
- Fake shell that imitates a Linux machine and logs every command
- Analytics on the most common passwords and commands
- World map of where attempts come from
- Strong isolation: its own VM, a container, and no outbound network
- Automatically generated weekly threat summary
Bonus: A write-up analyzing one week of real attack data, published alongside the repo.
Security · Advanced · 2 weeks
End-to-End Encrypted File Sharing
Share files by link, with encryption done in the browser so the server never sees file contents or keys.
- TypeScript
- Web Crypto API
- Node.js or Go
- S3-compatible storage
Features
- AES-GCM encryption in the browser, with the key kept only in the URL fragment
- Chunked streaming encryption for large files
- Links that expire or stop after a set number of downloads
- Optional password protection with proper key derivation
- A written threat model in the README
Bonus: A verification page that shows the stored ciphertext is unreadable without the link.
Games · Advanced · 2–3 weeks
Multiplayer Arena with Real Netcode
A fast top-down browser arena game with an authoritative server, client-side prediction, and lag compensation, so it feels smooth even at 150 ms ping.
- TypeScript
- HTML Canvas or Phaser
- Node.js
- WebSockets
Features
- Authoritative server running at a fixed tick rate
- Client-side prediction with server reconciliation
- Entity interpolation for other players
- Lobby and simple matchmaking
- Built-in network simulator with latency and packet-loss sliders
Bonus: A replay system that records inputs and plays back any match deterministically.
Games · Intermediate · 2–3 weeks
Procedural Roguelike with ECS
A turn-based dungeon crawler with procedurally generated levels, built on an entity-component-system architecture.
- Rust + Bevy
- or C# + Godot
- WebAssembly build
Features
- Seeded dungeon generation using BSP or cellular automata
- Entity-component-system architecture for all game objects
- Field of view and A* pathfinding for enemies
- Items, inventory, and save/load
- A playable web build published on itch.io
Bonus: A daily seeded challenge where everyone plays the same dungeon.