The fitness app that doesn't even know who you are.
No account. No server. No cookies. Just you, your phone, and an app that minds its own business. cronowiz is a free PWA that runs entirely on your device — your data never leaves. Ever.
While the rest of the fitness world asks for your email, credit card and blood type before you take a single step, cronowiz works the other way around.
open and go, like your running shoes
no server receives your data, because there is no server. Full stop.
the only thing we track is your workout, and we only do it on your phone
data lives in IndexedDB, in your browser. Delete the app and it's gone. Want a backup? You encrypt it yourself with a passphrase.
Google just renamed Fitbit Premium to "Google Health Premium", bumped the price by $20/year, and added an AI coach that needs your biometric data in the cloud to tell you to take more steps. We give you load monitoring, readiness, HRV and adaptive programs — and the most it knows about you is an optional nickname.
| label | Google Health Premium | cronowiz |
|---|---|---|
| Price | $9.99/month ($99.99/year) | Free. Forever. |
| AI Coach | Gemini tells you to sleep more (thanks, Gemini) | Your TSB tells you whether you can push or need to recover — without sending your data to Mountain View |
| Requirements | Pixel Watch or Fitbit + subscription | A browser. Any browser. |
| Your data | On Google's servers, with "science-backed guidance" | On YOUR phone, with math you can verify |
| To deactivate | Cancel the subscription, pray they delete everything | Delete the app. Done. Nothing else to wipe elsewhere. |
Price
Google Health Premium
$9.99/month ($99.99/year)
cronowiz
Free. Forever.
AI Coach
Google Health Premium
Gemini tells you to sleep more (thanks, Gemini)
cronowiz
Your TSB tells you whether you can push or need to recover — without sending your data to Mountain View
Requirements
Google Health Premium
Pixel Watch or Fitbit + subscription
cronowiz
A browser. Any browser.
Your data
Google Health Premium
On Google's servers, with "science-backed guidance"
cronowiz
On YOUR phone, with math you can verify
To deactivate
Google Health Premium
Cancel the subscription, pray they delete everything
cronowiz
Delete the app. Done. Nothing else to wipe elsewhere.
Privacy alone isn't enough. A safe but boring app is like an empty gym with a great alarm system. cronowiz is also — and above all — fun.
Run through an autumn forest generated in real time, cycle along a beach at sunset, jog through a neon city at night, or dive into an underwater world with bubbles and caustics. Every session is different — terrain is generated procedurally with Perlin noise, trees place themselves, the sun sets while you run.
| label | Zwift | Kinomap | cronowiz |
|---|---|---|---|
| Price | ~€17.99/month | ~€11.99/month | Free |
| Worlds | Watopia and friends (gorgeous, static) | Real videos (nice, pre-recorded) | Procedural biomes (endless, different every time) |
| Internet required? | Always, mandatory | Mandatory for streaming | No. Works in basements, on mountains, anywhere |
| Companion | Other online users' avatars | None | Your virtual ghost runs with you — or against you |
| Your data | Zwift cloud | Kinomap cloud | Your phone |
| In one word | Cycling MMO | Netflix of fitness | Your private playground |
Price
Zwift
~€17.99/month
Kinomap
~€11.99/month
cronowiz
Free
Worlds
Zwift
Watopia and friends (gorgeous, static)
Kinomap
Real videos (nice, pre-recorded)
cronowiz
Procedural biomes (endless, different every time)
Internet required?
Zwift
Always, mandatory
Kinomap
Mandatory for streaming
cronowiz
No. Works in basements, on mountains, anywhere
Companion
Zwift
Other online users' avatars
Kinomap
None
cronowiz
Your virtual ghost runs with you — or against you
Your data
Zwift
Zwift cloud
Kinomap
Kinomap cloud
cronowiz
Your phone
In one word
Zwift
Cycling MMO
Kinomap
Netflix of fitness
cronowiz
Your private playground
Zwift is great if you want to ride with thousands of strangers and pay almost as much as Netflix. Kinomap is perfect if you love real-route videos. cronowiz is for those who want worlds generated on the fly, zero latency, zero subscription, and the certainty that no server knows where you're riding.
Levels and XP
every session counts, from warm-up to PR
Daily Ring
close your daily rings (cardio, strength, steps)
Streak
your consecutive-days record, with realistic decay
Achievements
badges for real milestones, not for opening the app
Gems and cosmetics
collect gems in 3D worlds, unlock color variants (winter forest, tropical beach, rainy city…)
Collectible stickers
because adults deserve trading cards too
Real races — no followers, no public leaderboards, no social network in the middle. Just you, an opponent and the road.
Ghost run
pick one of your past runs and a virtual runner sets off at your recorded pace. An arrow points toward the ghost, with the gap in metres and an ahead / behind / tied label.
Repeat-track
a loop you have run before comes back as a faint ghost line on the map, and a voice navigator calls out every turn — "in 80 m, turn right". The same route is grouped into one circuit in the diary instead of fragmenting into a dozen unrelated entries.
LiveRoom
run live with a friend who is moving now: create a code, they join, and the map splits in two with their dot, their pace and the cadence delta beside yours.
Challenge a friend
pack the route, the pace and the stats into a .cwchallenge file. They open it, accept, and you become their ghost — even from another continent, even on a treadmill. At the end, a verdict: who won, by how many seconds, by how many calories.
Pacer AI
running solo? Pick a target pace and a pacer that never tires sets off down the strip. Beat it, or hold on.
Tempo
turn the run into a countdown. At zero cronowiz says "Target reached!", buzzes three times and the timer flips to counting up — because beating your target is the point.
No friends to follow, no leaderboard, no social graph. The race is a file or a direct room between two phones. Full stop.
The third treadmill scene, alongside YouTube and Scenario 3D: a stream of content that scrolls in front of you and reacts to how you are running. Not a tablet with the news propped on the console — a schedule built by the session you are in.
Live commentary
kilometre done, heart-rate zone change, pace change, final minute: when something happens the stream breaks in and tells you, with your actual pace instead of an adjective.
Dashboard cards
current pace, distance, heart rate, energy, cadence. Big numbers, readable while you run, without touching anything.
Compared to your own history
"12 s/km faster than your average", "best pace in the last three weeks". The comparison is with you, not with a leaderboard of strangers.
Opening briefing
today's form and your last run, served before the first kilometre starts.
Facts, quizzes and news
dated facts turned into questions you answer while running, and the RSS feeds you choose yourself. Nothing repeats: it remembers what you have already seen.
On the TV too
in cast mode the phone generates and the TV draws. Big targets and minimal controls, because you are running at the time.
The three scenes are mutually exclusive and none of them needs a backend: the browser reaches the feeds directly. The schedule is built by your session, not by a recommendation algorithm.
Got a TV? Got a phone? You've got a gym.
YouTube videos on the big screen
while your phone tracks
3D worlds projected on TV
the forest on a 55-inch hits different
Real-time metrics
HR, pace, distance — all on the TV
The phone stays the brain
sensors, BLE, audio all run there. The TV is just the "cinema".
No Chromecast required. No dongle. No account. Open the browser on the TV, scan, run.
cronowiz has a research-lab side you don't expect from a free app.
Your phone's camera becomes your form coach. MoveNet analyses your movements frame by frame, all locally: a live skeleton is drawn on screen, reps only count when the movement is clean, and a banner tells you what to fix while it is still fixable.
Put your finger on the camera and cronowiz measures your heart-rate variability with a full PPG pipeline, in 60 seconds. With a Polar H10 it reads the RR intervals straight from the strap instead.
A Tone.js synthesizer generates music in real time that adapts to your heart rate. No Spotify, no licensing.
cronowiz hosts a language model that runs entirely on your device, in WebGPU. No API, no cloud, no prompts shipped to a server: the intelligence is local, like everything else.
On-device LLM via WebLLM
Llama 3.2 1B by default, or Gemma 2 2B as an opt-in "Coach Plus". Weights live in OPFS and survive updates: you download ~700 MB once, then it's back in seconds.
"Explain today"
tap the readiness pill and the coach explains in three or four sentences why you are in PUSH, MODERATE or RECOVER today — citing your real numbers (TSB, recent RPE, last session).
Coaching chat
a persistent thread that knows your profile, your load, today's adaptation and your last 7 sessions. It cites concrete facts instead of inventing them: "nice work on yesterday's 5K, RPE 7 in 31 minutes".
All local
the conversation stays on the phone and rides into the encrypted backup. The model weights don't — they're regenerable. Not a byte of your training leaves the device.
It's no substitute for a doctor, a physiotherapist or a personal trainer — and it says so explicitly. Its job is to make your data legible and your plan adaptable, without anyone else seeing it.
The phone records. The dashboard is where that becomes readable: same principle — free, no account, nothing leaves your browser — with the screen space and the maths a five-inch screen cannot have.
Form over time
fitness, fatigue and form on the Banister model, plus acute-to-chronic workload ratio.
Digital twin
it projects your form forward from a hypothetical load, and tells you when it doesn't have enough history to try.
AI reports, on your endpoint
a language model you host yourself — typically an Ollama on your own network — reads the computed metrics and writes.
Straight from the phone
a QR or a six-character code and the backup moves device to device, without touching a server.
free, runs in the browser, asks for nothing.
works offline, weighs nothing, doesn't bite.
Prefer a native Android experience? You can find cronowiz on the Play Store. Same privacy, zero accounts, no compromises.
Yes. It is not a freemium product with the useful features locked behind a subscription — there is no paid tier at all. There are no ads, and we do not sell data, because we never receive any.
No. There is no sign-up, no email to enter and no cloud profile. Open the app, pick a workout and start. You can set a nickname, and even that is optional.
On the device, in the IndexedDB of your browser or of the installed app. There is no cronowiz server to receive it. If you want to move it, you export an encrypted .cwbackup file with a passphrase you choose, or send it straight to another device over WebRTC.
Yes. It is a progressive web app: after the first load the timer, programs, diary and strength sessions all work with no connection. Outdoor running uses GPS, which needs no network.
No. The language model runs on your device through WebLLM and WebGPU: the weights are downloaded once and kept locally, and the prompts never leave the phone. If your device has no WebGPU the coach simply stays off — everything else keeps working.
No, but it helps. Without one cronowiz estimates heart rate with the Tanaka curve outdoors and a two-state work/rest model in the gym. Pair a Bluetooth strap and the estimate steps aside for the real signal. With a Polar H10 it also reads RR intervals for strap-grade HRV.
Any modern browser: Android, iPhone, tablets, computers, and even a TV browser in TV Hub mode. On Android there is also a native app on the Play Store. A few features depend on hardware: camera HRV needs the torch and is not available on iOS, and the AI coach needs WebGPU.
Fourteen: English, Italian, Spanish, French, German, Brazilian Portuguese, Russian, Turkish, Indonesian, Hindi, Bengali, Simplified Chinese, Japanese and Korean.
cronowiz is the app on your phone: it records the training. cw·dashboard runs in the browser and reads that history on a big screen, with analyses that would not fit on a phone. Both are free, and the data moves between them by QR, code or file — never through a cloud.
