Ischys · ΙΣΧΥΣ

A private, on-device workout tracker. Ischys (ἰσχύς) is Ancient Greek for strength. Your entire training log lives on your phone — no account, no server, no cloud. Nothing ever leaves the device.

⬇︎ Download on the App Store · free · iPhone. Or build it from source — it's open, MIT-licensed, and the whole thing runs on-device either way.

The design is a precision instrument: monochrome, near-black, sharp, and legible mid-set with sweaty hands. Big number targets, previous-session references one tap away, and the accent colour reserved for a single action — completing a set.

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What it is

• 100% on-device. Install and start tracking immediately. No sign-up, no backend to run. The app is a self-contained React Native / Expo app with a local SQLite database and all the training logic (volume, estimated 1RM, PR detection, streaks, charts) running in TypeScript on the phone.
• Private by construction. Because there is no server, your data can't be collected, sold, or breached. It backs up with your normal device backup (iCloud), and you can export a JSON/CSV copy anytime.
• Yours to build. MIT-licensed. Clone it, build it, run it, change it.

Features

• Log workouts (weight × reps), warmup / drop / failure set types, rest timer.
• Routines — build them, start a session that prefills from your last session (progressive overload), save a finished workout as a routine.
• Personal records (best set, est. 1RM, best volume, max reps) detected on finish, with per-exercise history and charts.
• Profile stats — workouts, volume lifted, weekly training bars, streaks.
• Apple Watch companion (mirror + control a live workout), Live Activity on the Lock Screen, and Apple Health (heart-rate read, workout write).
• Export / import — a JSON or workout CSV, for backup or moving in from another tracker.
• Bodyweight movements count toward volume — set your weight manually or pull it from Apple Health, snapshotted per workout so past sessions keep their numbers.
• Merge duplicate exercises without losing history or PRs.
• 736-exercise catalog bundled in the app — names, muscles and instructions from free-exercise-db (public domain). Its exercise photographs are deliberately not used; see NOTICE.
• Line-art illustrations for the common movements, animated through the rep, on the exercise screen and the Lock Screen card. Artwork from Workout Guide / Everkinetic, CC BY-SA 4.0. Coverage is partial on purpose: an illustration is only shown when it depicts that exact movement, so the rest of the catalog shows initials rather than a wrong picture.

Platform support

iOS only, for now. Ischys is built and tested on iPhone (iOS 26, Expo SDK 57), and its headline features — Live Activity, the Apple Watch companion, and Apple Health — are iOS-specific with no Android equivalents yet. It's a React Native / Expo app, so an Android build is possible in principle, but it has never been built or run on Android and is entirely untested there. Treat Android as unsupported until someone does that work — contributions welcome.

Stack

React Native + Expo SDK 57 (New Architecture), expo-sqlite + Drizzle ORM for the on-device database, TypeScript throughout. Native modules for the Watch companion, Live Activity, and HealthKit live under frontend/modules/ and frontend/targets/.

Ischys/
└── frontend/
    ├── app/            screens (expo-router)
    ├── src/
    │   ├── db/         SQLite schema, migrations, bundled catalog seed
    │   ├── data/       local repository (the app's data layer)
    │   ├── domain/     pure training logic (stats, records, streaks…) + tests
    │   └── components/ UI
    ├── modules/        local native modules (Live Activity, HealthKit)
    └── targets/        Apple Watch app + Live Activity widget

Build & run

Ischys is on the App Store (free) if you just want to use it. To build it yourself, you'll need macOS with Xcode (for the iOS build) and a free Apple developer account to sign it onto your own device.

cd frontend
npm install
npx expo run:ios --device   # build + install on a connected iPhone
# or drop --device to run in the iOS Simulator

The app opens straight to your training — there's no server to point at and no sign-in. npm run typecheck and npm test (pure-logic unit tests, run in both UTC and a non-UTC timezone) gate every change.

Licence

The code is MIT — see LICENSE. Clone it, build it, ship it.

The bundled exercise artwork is not MIT. It is Workout Guide / Everkinetic line art under CC BY-SA 4.0, which permits commercial use but asks for credit, a link to the licence, a note of what you changed, and that adaptations of the artwork stay under CC BY-SA 4.0. If you reuse this repo, carry that attribution across — it applies to frontend/src/data/exerciseArt.generated.ts and the widget's ExerciseArt image set, not to the code around them.

Fonts are under the SIL Open Font License. Full details and the exact changes made to each are in NOTICE.