Live demo, open source

Daily streaks that stay correct across time zones and DST

Move the clock, skip days, fly across zones and cross daylight saving changes. Every streak, level, quest and rank on this page is computed in your browser by the library's own code from src/.

Zero dependencies JavaScript and PHP 217 shared test vectors

Try a scenario

User's clock

Move time

Act

Settings

Time zone (change it to travel)

Grace window

Day starts at

Streak

Level

Quests

Weekly leaderboard

Ties

What happened

Last library call

The exact input and output of the most recent call, straight from the library.

Use it

Load the state you store, call a function, save the state it returns. Instants are integer Unix seconds and zones are IANA names.

npm install github:moonetix/gamification-kit

import { checkIn } from 'gamification-kit';

const { state, result } = checkIn(saved, {
  at: Math.floor(Date.now() / 1000),
  timeZone: 'America/New_York',
});

A PHP port with the same option names and the same test vectors lives in php/. Use these mechanics for XP, levels and badges, not for currency that has money-like value.