Why I Built Ghorobi / Another Calendar App

Yes, another calendar app. Almost every calendar starts from the same assumption: an hour is sixty minutes. Ghorobi starts by dropping it.

For most of history, the world told time by the sun. Ancient Egypt, Greece and Rome, Jewish tradition, the Islamic world, medieval Europe, and Japan until the 1870s all used hours that followed the daylight.

Those hours stretched in summer and shrank in winter, until mechanical clocks froze the hour at sixty minutes.

Sunrise and sunset set your body's clock, not the number on a clock. So I decided to build the app for that.

The name comes from the Arabic word for sunset.

Ghorobi works out your local sunrise and sunset, then splits the day into 12 sun hours and the night into 12 more. There are no time zones to configure, and you can switch back to clock hours at any time.

Instead of picking 21:30, you pick an hour like Darkness or Deep Night, and Ghorobi shows roughly when that lands today. Plans move with the seasons, so morning always means morning.

The day starts at sunset, as it does in the Islamic calendar and many other traditions: the night hours come first, then the day hours from sunrise.

The five daily prayers are optional. Turned on, they take their place among your hours, calculated for where you are, with a choice of calculation method and Asr madhhab. Prayer reminders are free, always.

Sunrise, sunset and prayer times are worked out on your device, so your location stays on your phone. There are no ads. The app is fully translated into Arabic and English, right to left included, and it tracks your habit streaks alongside your plans.

The first commit landed in July 2026 and Ghorobi reached the App Store on September 28, 2026. It's built with Flutter, with Supabase for accounts and sync and RevenueCat for Ghorobi Pro, which adds sync across devices, task reminders, sun alerts and custom repeats.

Ghorobi is free on iPhone, iPad and Android at ghorobi.app.