Case study
Vector: my day in one direction
A native iPhone and Apple Watch app I built for myself: workouts, food, water, spending and calendar in one place, with an arrow that shows how far along the day I am.
It isn't on the App Store. I use it every day and show it here as a project. The screens on this page are mock-ups with sample data.
- 9modules in a single app
- 4targets: iPhone, watch, widgets and complications
- ~22,000lines of Swift
- ES · ENfollowing the device language, in light and dark
The idea
One arrow instead of six rings
Each day has a handful of goals: eat enough, drink, train if it’s a training day, the English question, the tasks. The number counts the ones you’ve met. The arrow counts partial progress too, so it moves even before you’ve closed any of them.
- Only what makes sense today counts: on a rest day, the workout goal isn’t there.
- The same calculation on the iPhone, the watch and the widget.
Workouts
The training month at a glance
Four weeks in a grid: the previous two, the current one and the next. Done days are filled and planned ones are outlined, so what happened and what’s coming never get mixed up.
- Running in orange and gym in indigo; if a day has both, half and half.
- Done days come from Health, planned ones from the system calendar.
Apple Watch
The whole app on your wrist
It isn’t a remote for the iPhone. The watch has nine pages, one per module: you log water, food or an expense right there, start the gym routine or the run, and everything syncs back to the iPhone. It also ships complications for the watch face.
Running coach
A race plan that knows when to back off
The watch reads races from the calendar and sets up the goal: distance, time and an even pace. During the run it shows how far ahead or behind you are. But heart rate comes before pace.
- With a sustained high heart rate it won’t ask you to speed up, even if you’re behind.
- If the plan is no longer reachable without overreaching, it adjusts to a realistic finish.
- With heat in the forecast it offers a longer target before you start and is more cautious during the run.
Widgets
What matters, without opening the app
Widgets for the Home Screen and the Lock Screen, in the same style as the app and following the system’s light or dark appearance. Rest between sets shows up as a Live Activity.
- Log water straight from the widget, without opening the app.
- This month’s spending with the month-end projection.
CarPlay · StandBy
The training month, on the dashboard
The workout calendar also lives on the car screen. It’s designed for that place: large numbers, nothing to tap and no battery drain, because it only redraws when a day changes.
- The same widget works in StandBy, with the iPhone charging in landscape.
Everything inside
Nine modules, one app
A projected time for every race
It reads races from the calendar, estimates your time from your recent runs and gives you the pace per kilometre. Splits, heart-rate zones and cadence, live.
Routines you follow from the watch
An exercise catalogue, sets with last time’s reference, and a rest timer that stays visible even with the iPhone locked.
A calorie goal that moves with you
Resting energy plus the real activity Health measures, so it rises through the day. Thousands of foods offline and a barcode scanner.
How the month will end, not just how it's going
A budget per category, yearly costs spread month by month, and a month-end projection that accounts for pending fixed costs and your variable spending rate.
Log in one tap, from wherever you are
From the app, the watch, the widget or the watch face. The litre goal is yours, and creatine is ticked off when you take it.
Every event, with its forecast
System calendar and reminders in one view. Next to each event, the forecast for that place and time, and a heads-up beforehand if rain, heat or an official warning is coming.
One question a day
B2 and C1 vocabulary and expressions, answered from the iPhone or the watch. It counts as a goal for the day.
XP, levels and medals
Everything you do adds up. More than a hundred medals and a streak that rewards consistency, not one-off days.
What moves together in your days
It cross-references food, spending and training over the last 120 days: Pearson correlation with its confidence interval, a significance test and day-to-next-day relationships. It shows the scatter plot, not just the number.
How it's built
Native, no server and no accounts
Everything lives on the iPhone and the watch. Health data comes from Health, the schedule from the system calendar, and weather from a public forecast. There’s no backend and no sign-up: the iPhone and the watch talk to each other directly and each keeps its own data.
The interface uses a palette with two values per colour, so the app and its widgets follow the system’s light or dark appearance, and every string exists in Spanish and English.
- Role
- Author · design and development
- Period
- 2026
- Organization
- Personal project
- Stack
- SwiftSwiftUISwiftDataHealthKitWidgetKitWatchConnectivityEventKitApp IntentsSwift Charts