About

Built by one engineer, not a company

Marcus Gilchrist
Marcus Gilchrist
Software & hardware engineer — previously Google, Uber, Microsoft, and Intel

I spent my career as a software developer and computer hardware engineer, working on mapping, AI, and infrastructure at places like Google, Uber, and Microsoft, and on computer architecture at Intel before that. Along the way I kept running into ideas that were technically interesting but never had a business case big enough for any of those companies to actually build.

Kardiacs is what happens when I stopped waiting for one. I finally get to build the things I actually wanted to use, myself — and give them to anyone else who wants them too.

The one real cost here is data — maps, routing, and syncing all cost money to run at scale, and that's exactly what the ads pay for. The best way to support the project is simpler than that, though: use the app, and tell someone who'd genuinely like it. Questions? Get in touch.

Follow along

The writing, and the places

Two accounts, both worth what you pay for them.

The Kardiacs Substack archive, listing the posts “Where the Model Runs” and “The Plausibility Tax”
The Kardiacs newsletter kardiacs.substack.com

Longer writing about building this thing — where the model runs, what an AI pair actually costs you in testing and review, and whether any of it is the next big thing or a fad.

Read the newsletter →
The @kardiacs.llc Instagram grid: a hanging valley lake, the Milky Way, a lake seen from a stone tower, an empty beach, palms at sunset, and a fjord under snow-capped peaks
@kardiacs.llc instagram.com/kardiacs.llc

Where the app gets used and tested, mostly: mountains, coastlines, a fjord or two.

Follow on Instagram →

Both are captures of the real pages rather than embeds, so nothing here is watching you read it.

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.

Get Kardiacs — free Get Kardiacs — free

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