How to Build a Daily Challenge Feature Without Any Backend or Database

A developer behind Classroom Games, a free learning platform for teachers, has shared a technique for powering daily rotating challenges using only client-side JavaScript. The approach uses a deterministic hash function applied to the local date string, ensuring every user on the same calendar day sees the same category pick without any server calls. To avoid the same category appearing on consecutive days, the algorithm checks the previous day's result and steps forward one index if a collision is detected. Player progress is stored in localStorage under a date key, with error handling included for school-managed browsers that may restrict or clear site data. The method requires no accounts, no cron jobs, and no API, making it lightweight enough to reset automatically at each user's local midnight.