Lose the signal. Keep the group.

Your group talks, chats and shares one live map with zero bars — phone to phone, up to 200 m rider to rider and relayed further down the line.

Free, paid for by ads. Nothing to buy. · No account needed.

This is the moment other apps go quiet.

  1. A trail dropping into a river valley, the road ahead out of sight

    The group splits on the descent.

  2. Lose the signal.

  3. The group chat on a climb: a message from Ben and both riders' microphones open, every rider on the map behind

    Keep the group.

    Everyone still hears you. And sees you.

Ride together

Your group, in your ear. No signal. No server.

  • Talk hands-free

    Unmute and the group hears you. Push-to-talk if you prefer.

  • One live map

    Everyone’s dot, on every phone. See who’s behind.

  • Words, too

    What you say is typed into the chat, so a rider out of voice range still reads it.

  • Stretches with the group

    Up to 200 m rider to rider, and further as phones relay it down the line.

Join in five seconds: scan the leader’s QR code. No account.

How it works →

Voice: iPhone 12 or later on iOS 26.4+ with other iPhones; Android 13+ with Wi-Fi Aware with other Androids. Map, chat and photos work between any phones. Range varies with terrain. Encrypted between phones — nothing reaches us.

A Kardiacs group chat on a climb: messages from Ben and the rider, with both riders' microphones open
A live run in Kardiacs navigating a trail loop, with the next turn called and the pace on screen

Say it. It’s written down.

Hands on the bars, gloves on. Tap once and talk — the gate, the water, the bad corner — and it’s a note. On your phone, nowhere else.

The Kardiacs notepad mid-ride, holding three spoken notes about a gate, a water fountain and a rough descent

Ride in a minute.

  1. Download. No account, no sign-up wall.

  2. Tell it your age and weight — or connect Health — for zones from day one.

  3. Pick Explore, Commute or Indoor. Go.

Bringing history? Import your Strava or Garmin archive, or any FIT file.

Questions

Is it really free?

Yes. Ads pay for the maps and servers. There is no paid tier and nothing to buy.

Do my friends need the app too?

Yes — it is phone to phone. They join by scanning your QR code, with no account. Riders can be up to 200 m apart, and further as phones relay it along the group.

Does it work on Android?

Yes. The map, chat and photos work between any phones running Kardiacs. Group voice works iPhone to iPhone (iPhone 12 or later, iOS 26.4+) and Android to Android (Android 13+ with Wi-Fi Aware).

Does it work with my trainer, watch or bike computer?

Bluetooth FTMS and Wahoo smart trainers, power meters and heart-rate straps pair directly. There is an Apple Watch app. Routes and workouts go out to your bike computer, and the rides it records come back in.

Do I need an account?

No. There is no sign-up wall. Sign in with Google or Apple only when you want your history, routes and gear to follow you between devices and into the web planner.

More questions, answered →

Saturday’s better with everyone on it.

or

Why is it free?

Free, paid for by ads. Nothing to buy. The ads pay for the maps and servers.

Ride in a minute.

  1. Download. No account, no sign-up wall.

  2. Tell it your age and weight — or connect Health — for zones from day one.

  3. Pick Explore, Commute or Indoor. Go.

Bringing history? Import your Strava or Garmin archive, or any FIT file.

Questions

Is it really free?

Yes. Ads pay for the maps and servers. There is no paid tier and nothing to buy.

Do my friends need the app too?

Yes — it is phone to phone. They join by scanning your QR code, with no account. Riders can be up to 200 m apart, and further as phones relay it along the group.

Does it work on Android?

Yes. The map, chat and photos work between any phones running Kardiacs. Group voice works iPhone to iPhone (iPhone 12 or later, iOS 26.4+) and Android to Android (Android 13+ with Wi-Fi Aware).

Does it work with my trainer, watch or bike computer?

Bluetooth FTMS and Wahoo smart trainers, power meters and heart-rate straps pair directly. There is an Apple Watch app. Routes and workouts go out to your bike computer, and the rides it records come back in.

Do I need an account?

No. There is no sign-up wall. Sign in with Google or Apple only when you want your history, routes and gear to follow you between devices and into the web planner.

More questions, answered →

Saturday’s better with everyone on it.

or