About CAlarm
Updated
CAlarm is an iPhone app for alarms that take a date as well as a time. It is built and published by LegStart, a mobile app developer in Japan, and the articles on this site are written by the developer himself.
Who builds CAlarm
- App
- CAlarm (Japanese name: カラーム)
- Published by
- LegStart (株式会社LegStart, legstart.com)
- Business
- Mobile app development
- Developer
- Takuma Yoshimura, Developer of CAlarm
- Requires
- iOS 26.0 or later
- Contact
- Contact form
Why I built it
CAlarm exists because of problems I kept having myself.
I overslept for work because I forgot to set an alarm the night before. I missed a commitment months out because I forgot it entirely. Putting things in a calendar did not fix it: what a calendar sends is a notification, and a notification stays silent on silent mode and slips past you when you are busy with something else.
What I needed was not a notification but an alarm — and not the built-in one, which only takes a time, but one I could set for “15 April, 2:30 PM” so it rings on that day and no other.
The bar was the built-in Clock app: I wanted the same force behind it. AlarmKit in iOS 26 is what made that possible. CAlarm registers its alarms with iOS as alarms, so they ring at ringer and alarm volume even on silent or in Focus, and take over the Lock Screen.
— Takuma Yoshimura, Developer of CAlarm
How these articles are written
The use cases and the guide are written by the developer, against the app’s actual implementation and behaviour on a device. Nothing that is not in the app gets described here, and no number goes in that has not been checked.
When usage data is published, the period and the method of aggregation are stated in the article and only anonymous aggregates are shown — see which alarm sound people actually pick. Figures whose meaning cannot be explained are not published at all.