Rep Track

A personal workout tracker for a fixed weekly plan: open it at the gym, log your sets, and let it tell you what you lifted last time. Everything is stored locally in your browser — no account, no backend, no data leaving your device.

Live: https://rep-track-ten.vercel.app

Features

• Two built-in plans — a barbell strength A/B (heavy low-rep compounds plus accessories) and the original dumbbell hybrid A/B, both defined in code. Pick the active one under Settings → Training plan; the choice is remembered per device and applies before the page paints. Each exercise shows target sets × reps, muscles and movement type, with a form-video link and a link to its page in the WWWorkout exercise catalogue. Switching plans moves nothing: History, Stats, Records and Compare read across both plans, so a non-active plan's exercises still count toward their real muscle groups.
• Planner — build your own plans: training days, exercises picked from the WWWorkout catalogue (search by name, filter by muscle or movement), sets × reps. Start from scratch or a copy of a built-in plan; up to ten plans per device, selectable in Settings like the built-ins.
• Set logging — weight + reps per set, grouped into one session per training day and calendar date. A "last time" reference shows the previous session's sets for each exercise, set by set, to drive progressive overload.
• Personal records — estimated one-rep max (Epley) per exercise; a PR badge highlights the actual logged set behind a new record.
• Rest timer — starts automatically when you log a set (default 2:00, configurable presets, ±15 s mid-rest), with a completion chime, vibration, and a screen wake lock while it runs.
• History — every session set by set, most recent first.
• Stats — volume/reps per session, per-exercise totals, and exercise trends over time (including estimated 1RM), filterable by date range; view state lives in the URL.
• Compare — import a training partner's exported backup to compare records and volume side by side; it stays on this device and is never merged into your own history.
• Backup & restore — export the whole history and your custom plans as a JSON file and import it on another device, either merged into or replacing what's there. A reminder nudges you when unbacked-up sessions accumulate.
• Settings — training plan, light/dark/system theme, kg or lb, and rest-timer length.
• Offline-ready PWA — a service worker keeps the app shell available when the gym's signal drops; sets are logged to localStorage regardless.

Tech stack

Next.js 16 (App Router, React 19, static prerender) · Tailwind CSS v4 · shadcn/ui (base-nova on Base UI) · Recharts · TypeScript · vitest · oxlint + oxfmt · pnpm. Originally scaffolded with v0.app.

Every route is statically prerendered and all training state lives in localStorage (treated as a trust boundary — stored payloads are runtime-validated on load). The only server-side work is fetching exercise metadata from the WWWorkout catalogue, revalidated hourly (ISR); set WWWORKOUT_URL to point at another catalogue instance (default https://wwworkout.vercel.app).

Getting started

pnpm install
pnpm dev        # http://localhost:3000

Command	What it does
pnpm build / pnpm start	production build / serve it
pnpm test	vitest unit tests (pure logic in lib/)
pnpm typecheck	tsc --noEmit
pnpm lint / pnpm lint:fix	oxlint
pnpm format / pnpm format:check	oxfmt
pnpm perf:bundle	per-route bundle drift vs the recorded baseline (after pnpm build)
pnpm perf:latency	TTFB percentile smoke against $PERF_BASE_URL
pnpm catalog:sync	refresh the offline catalogue snapshot from WWWorkout

CI runs formatting, linting, type-checking and tests on every push and pull request, alongside three scanning layers: a production dependency audit, CodeQL static analysis (SAST), and a gitleaks secrets scan. Performance checks live in perf/, deliberately outside the CI test path.

Customizing the plan

The workout plans are data, not UI. Each plan is one module — lib/plan-barbell-strength.ts, lib/plan-dumbbell-hybrid.ts — holding a WorkoutDay[]; edit one to change days, exercises, or targets (or build your own in the Planner, no code needed). To add a plan, write a third module, register it in lib/plans.ts, and add its selector pair to the reveal rule at the bottom of app/globals.css.

Two identifiers are load-bearing:

• Day ids key sessions. A session is stored against (dayId, calendar date), so renaming a day id detaches every session already logged under it. Ids must also be unique across plans.
• Exercise names are the join key to logged history. Renaming an exercise starts a fresh history for it; reusing a name across plans deliberately shares one history (which is why Romanian Deadlift, Incline Dumbbell Press and Lat Pulldown appear in both plans).
• Exercise names are also the join key to the WWWorkout catalogue. Plan files only declare name, sets and reps; muscles, movement, the video link and the WWWorkout detail link come from the catalogue, so every plan exercise must exist there under exactly the same name. Run pnpm catalog:sync to refresh the bundled snapshot (lib/catalog-snapshot.json) used when the catalogue is unreachable.

Data-integrity tests in lib/workouts.test.ts and lib/plans.test.ts guard all of it; custom plans built in the Planner are validated by lib/custom-plans.ts (tests in lib/custom-plans.test.ts).

Data & privacy

All training data stays in your browser's localStorage. There is no sync and no tracking of your training data; the only way it leaves the device is the backup file you export yourself. The only network request the app's server makes is fetching the public exercise catalogue from WWWorkout (refreshed hourly) — it sends nothing about you or your training. Device preferences — active plan, theme, units, rest length — live in localStorage too and are deliberately not part of the backup file, which holds sessions and custom plans only. Browsers may evict local storage under pressure — export a backup now and then (the app reminds you).

License

MIT