Circulus — Training Timer
Interval timer for groups
Only for iPhone
Free
iPhone
Build your routine from activities, rests, rounds and stations. Run it on your own or together on the same countdown. No account, no sign-up.
WHY CIRCULUS EXISTS
My boxing group worked through a lot of timer apps. None of them won us over: either features were missing, or the basics sat behind a paywall. So I built the app we should have had.
It was made for us — and built so that it works for anyone who knows the same problem.
FOR YOU
• Create and edit routines
• Add activities, rests, rounds and stations with parallel lanes
• Run it in overview mode (shows every parallel lane at once) or in station mode (you pick one lane per station)
• Write an introduction, add a Spotify or Apple Music link as a suggested soundtrack
WITH YOUR PEOPLE
• Send a routine as a link through any messenger — or as a file, and even the clips travel with it
• Group mode: set a start time, the others scan the QR code, every device counts the same countdown
• No account, no sign-up, no email invitations
FOR YOUR COMMUNITY
• Record your own clips and use them in activities
• Keep a profile, pass your routines on
• Link a YouTube video in the introduction
YOUR DATA STAYS ON YOUR PHONE
Circulus has no server. Routines, profile and settings live on your device and nowhere else — there is nothing to sync, because there is nowhere to sync to. Group mode works without any connection between devices either: the QR code shares the start time, and every device handles the rest on its own.
Routines leave your phone only when you deliberately share them.
FREE. COMPLETE.
Every feature is included. There is no pro version, no subscription, no locked switches — that was the reason to build this app in the first place.
Ads carry the running costs. They appear in the library and after a workout — never during a workout, never while sharing.
THE CLIPS THAT COME WITH IT
The five exercise clips Circulus ships with were generated with AI. They are there so the app is not empty on day one — the clips that matter, you record yourself.
The spoken cues are generated with AI as well.
QUESTIONS, IDEAS, BUGS
Write to me: support@circulus.training — or on X at @just_mazen.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Sometimes there just isn't time to plan a whole workout.
QUICK ROUTINES
You no longer have to build a routine to start a session of a few rounds with
activities and rests of the same length. Tap "+", choose "Quick", set the
repeats, set the times for activity and rest — and go. On your own or together,
by QR code as always.
The developer, Matthias Eitner, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Linked to You
The following data may be collected and linked to your identity:
- Location
- Identifiers
- Usage Data
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Diagnostics
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Matthias Eitner
- Size
- 13.6 MB
- Category
- Health & Fitness
- Compatibility
Requires iOS 26.0 or later.
- iPhone
Requires iOS 26.0 or later.
- iPhone
- Languages
- English and German
- Age Rating
9+
- 9+
- Contains
Advertising
User-Generated Content
Health or Wellness Topics
- Copyright
- © 2026 Matthias Eitner