World Cup bracket game with no back end – brackets live in the URL
Stores entire bracket state in the URL so you can share without login.

Stateless bracket sharing via 217-character URL encoding beats backend-dependent predictors.
Sports fans, World Cup followers, bracket prediction enthusiasts
FiveThirtyEight World Cup simulator · ESPN Bracket Challenge · FIFA official predictors
The calendar feature is nice. I wanted to build my own schedule for the games I was interested in. There is full calendar that you can subscribe to as well, that gets updated as the fixtures get decided. I also wanted to be able to interactively change things and visualize the whole knockout stage.
All the state is in the URL fragment. It's a handrolled compact byte format. About 203 bytes, ~217 characters. The URL has the full snapshot so the link you share always renders the same brackets. It's versioned so you can change the format not break links out there.
At this point it does everything I wanted it to do for me. Might be some real howlers in there. Let me know if you spot one.
Stores entire bracket state in the URL so you can share without login.
Another bracket prediction game, but themed for World Cup 2026.
203-byte custom URL encoding beats localStorage bracket predictors.
Entire 3D scenes stored in URLs—clever constraint, but limited by URL length and browser storage.
Another World Cup prediction pool when ESPN and Yahoo already do this free.
RFC 3676 thread parsing handles Gmail/Outlook quirks; solves a real sharing friction point.