Offline-First Fitness Tracking

Quickstart

Offline-first, the Kinoku way, means two things. Your training record lives on your phone. And the app works fully with no network. This is not an offline fallback. Offline is the default. Backup is a file you own. Import is a CSV you drop in. The cloud is a place that just two opt-in features reach into (Social Bets and a planned bring-your-own-key AI option). Everything else stays on your device.

What you get: faster launches, no account to recover, no data breach you never agreed to, no cloud lock-in on your subscription. What you give up: no auto sync across phones without a manual backup, no social feed, no exercise updates pushed from a server (the app ships them in updates).

For some people, none of these tradeoffs matter. For others, they are the whole reason to switch.

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Where consumer fitness apps put your data

A simplified map of the major apps:

App	Where your data lives	Account required
Strava	Cloud (primary)	Yes
Hevy	Cloud (primary)	Yes
Strong	Device (primary) + optional cloud sync	No (for free tier)
FitNotes	Device (primary)	No
Fitbod	Cloud (primary)	Yes
Whoop	Cloud (primary)	Yes + subscription
Garmin Connect	Cloud (primary)	Yes
TrainingPeaks	Cloud (primary)	Yes
Apple Fitness / Health	Device (iCloud optional)	Apple ID
Kinoku	Device only (core)	No

“Cloud (primary)” means the main copy of your training lives on someone else’s server. Your phone just holds a cache. If the service goes down or cuts off your access, your history is at their mercy.

“Device (primary)” means the opposite. The main copy lives on your phone. The cloud, where it exists at all, is just a place to export to.

Kinoku sits firmly in the device-first camp. There are two exceptions, both opt-in and narrow in scope. More on those below.

What offline-first by default means

Here is what Kinoku does not do.

1. No signup. No email, no password, no Google account, no phone number. You install the app and start logging.
2. No training record in the cloud. Your workouts, sets, routines, PRs, photos, and cycle data all live in a database on your phone.
3. No tracking by default. Diagnostics are opt-in inside the app. The website uses no analytics, cookies, pixels, or fingerprinting.
4. No “your data helps improve our models” clause. I don’t have your data to use.
5. No cloud needed for billing. The Play Store handles subscriptions. If Google Play can’t be reached, Kinoku holds a 7-day grace window on your last known tier. Your data is never held hostage.

Here is what it does do.

1. Full ZIP backup. Export the whole database, all your photos, and all your settings to a file you own. Restore it on any device.
2. CSV import from FitNotes, Strong, Hevy, Jefit, RepCount, Liftin, Fitbod, and Strava. One time, on your device.
3. Health Connect support. Read and write to Android’s own health store, which also stays on your device.
4. Wear OS companion. Your phone and watch sync directly to each other, not through a Kinoku server.
5. Trash with 30-day undo. Every delete can be undone. Every restore is lossless.

The two opt-in cloud features

To be honest, Kinoku does reach the cloud for two features. Both are opt-in. Both are narrow.

Social Bets

A way to bet with friends, built on Firebase. You can bet on workout counts, streaks, or total weight lifted. You share a bet by link or QR code. Progress syncs so both people see the same state.

If you never join a bet, Kinoku makes no cloud calls at all. The feature is fully optional. And the only thing in the cloud is the bet itself. The rest of your training record stays on your phone.

Bring-your-own-key AI (planned)

A planned option for power users to add their own OpenAI or Anthropic key. That key would turn on AI features that work over your local data. The call goes straight from your phone to the AI provider. Kinoku’s servers don’t sit in the middle. If and when this ships, you opt in by adding the key. No key means no AI calls.

That’s it. Everything else in Kinoku stays on your device.

Why it matters in practice

Most people who try Kinoku react to offline-first in one of three ways.

1. “Oh, that’s neat.” They don’t really care. It doesn’t slow them down. It works like a normal app. This is most people.
2. “Finally.” They’ve been burned by a service shutting off or changing terms. They want to own their data. This is the committed few.
3. “Wait, how do I sync?” They expect auto sync across phones, which Kinoku doesn’t do. The honest answer: back up the file, then restore it. It works fine. It is not magic.

Offline-first is not free. It has real limits. Put plainly: if you want sync across phones with zero thought, Kinoku will annoy you. If you want data you truly own, that is the whole point.

What owning your data really means

“Data sovereignty” gets thrown around until it means nothing. Here is what it means in Kinoku.

• Your training record is a file. A database plus a photos folder. Both sit in the app’s private storage on your phone.
• Backup is a ZIP. Email it to yourself, drop it in Drive, put it on a USB stick. You own the file.
• Restore goes anywhere. The same ZIP restores on a new phone, after a factory wipe, or on a newer Kinoku version.
• Export is CSV. Dozens of CSV files cover every part of your data. You can leave Kinoku and take your data. You can also import it back.
• No locked format. The ZIP holds a standard SQLite database. Anyone with a free SQLite tool can read it.

This is what the GDPR calls “data portability.” Article 20 says a service must let you export your data. Kinoku builds that in from the start, not as a bolt-on to please regulators.

Safety by not holding the data

A fitness service holding 50 million people’s training data is a target. Every quarter, one of them gets breached. Sometimes it’s password hashes. Sometimes it’s worse: run routes, recovery histories, body measurements, progress photos. The 2018 Strava heatmap leak, which traced out military bases from run routes, is the famous one. The quieter cases involve real people being stalked or identified.

The surest way for Kinoku to stay out of those breaches is to not hold the data at all. Call it safety by absence. Data can’t leak from a server that doesn’t exist.

This is why Kinoku has no accounts. An account would mean storing your login. Storing it would mean protecting it. Protecting it would mean running servers that could be breached. None of that exists here, because there are no accounts. The whole risk is designed away.

What you give up, in plain terms

Let’s name the costs.

1. No sync across phones. Want your workouts on two phones? Move a backup by hand. Not terrible. Not magic.
2. No social feed. No feed of what friends did. No global leaderboards. You share on purpose (a card, a link, a QR code) or not at all.
3. No server-pushed exercise updates. New exercises arrive in an app update. You can’t add one and have it spread to other users.
4. No crash data at scale. I can’t see “half of users hit this bug,” because I see nothing at all. Bug reports come by email.
5. No cloud AI (for now). Every AI feature runs on your phone. The heavy cloud features a Whoop or Future offer aren’t here. In return, the ones that ship are private and easy to explain.

If any of these feel like dealbreakers, Kinoku is not your tool. If they don’t, welcome.

Track this in Kinoku

The Backup & Import feature walks through the full backup and restore flow. The Strava Import page covers the CSV path for runners moving off Strava. The Trash & Undo feature explains the 30-day undo on deletes. The Data Sovereignty page maps out what stays on your device and what doesn’t.

References