• Matchmaking! Click on 'Find game' and get matched up against a random opponent.
• Rooms! If you want to play a friend, get a room!
• Dark mode! A chess website that has dark mode enabled by default? Unheard of!
• Local multiplayer! Pretty self explanatory; play with someone physically near you.
• Move validation! All moves are validated by the chess engine. Valid moves are displayed on clicking a piece. All forms of draws - stalemate, mutual agreement, threefold repetition, and insufficient material - are detected and handled.
• Timer! In online games, you and your opponent each get 10 minutes, exceeding which will result in a loss.
• Robust! As robust as I could make it, anyway. Should withstand temporary disconnection and browser reloads just fine.

NumChess? I'm sorry, haven't heard of it before. That's a weird name if I'm being honest. Does it have something to do with numbers?

- Hikaru Nakamura, probably

You should monetize this.

- My brother, when I averaged 10 website visits a month

React, Socket.io, Node.js, Material UI.

No database involved.