TRAVEL CLOCK · 2026 · DESIGNER AND BUILDER

A jet lag plan you can read at a glance

week solo sprint

321

commits with Claude Code

Overview

Travel Clock is an iPhone and Apple Watch app that shifts your sleep, light and caffeine a little each day before a flight, so you land closer to local time. I designed and built it on my own in ten weeks, with Claude Code as my engineering partner.

Role

Designer and builder

Timeline

Aug–Oct 2026

Platforms

iPhone, Apple Watch, widgets

APP STORE RELEASE IN PREPARATION

Contents

The idea

The app

AI workflow

Beyond the phone

Copy and localization

Where it stands

The idea

The problem. Jet lag apps sell maximal intervention: more steps, more alerts, more supplements. Most trips need far less.

The bet. A plan honest enough to tell you when to do nothing. A same-zone trip shifts nothing. Only a real time-zone jump earns the full ramp of light, sleep and caffeine.

The rule. The app is glanced at and closed. No streaks, no subscription, no data collected.

Home in dark mode: the classic clock face with London and Tokyo hands, three tiles and three cards

About you: wake time, bedtime and three quick questions

Where to: a globe with the London to Tokyo route and an eight hour offset

Caffeine: today’s cutoff at 13:30 and daily limits by drink

Home in light mode with the time rings clock face

The plan on the flight day, with the flight band and landing

Your plan: eight hours east, three days of shifting before you fly

Caffeine in dark mode after the cutoff: the Today bar turns red and reads Cutoff passed

Alarms in dark mode: wake, light, wind-down, exercise and travel days

The plan for today with bright light, last cup and bed

The app

Three cards, always. The home screen shows only what matters right now: the three actions that move your body clock most, in the order you will do them.

The tiles are the navigation. Plan, caffeine and alarms sit under the dial. No tab bar, nothing to learn.

TRIP SETUP

INSPIRATION

APP ICON, LIGHT AND DARK

AI workflow

I built Travel Clock with Claude Code: 321 commits, from a Claude Design prototype to a native app. The interesting part was not the code it wrote. It was the workflow that kept ten weeks of agent sessions consistent.

An excerpt of CLAUDE.md: if a request contradicts this file, say so before acting

Rules before prompts

Every decision lives in CLAUDE.md, so every session starts from the same rules.

The Destination sheet stacked on top of the Trip sheet, next to the sheet rules added to CLAUDE.md

Mistakes become rules

Destination stacked a second sheet on Trip. The fix shipped, and the sheet rules went into CLAUDE.md.

The city picker sheet beside measurements taken in the simulator at 3x

Verify in context

What touches the phone is measured in the simulator, not judged in a browser.

Diagram of where the Trip sheet broke Apple's sheet rule: Destination, Dates and Departures did, About you returned where you were

Map flow inconsistencies

An agent drove every flow and mapped where the Trip sheet broke Apple’s sheet rule.

Audit numbers: 8 flows driven, 30 findings, 19 items approved, 33 commits

Audit, then hand over

One agent audits, I decide, a second agent builds.

Beyond the phone

Widgets show the countdown and the day’s rhythm, square or wide, without opening the app.

Apple Watch carries the same tiles to the wrist, with today’s rhythm one scroll below.

The coach answers on the device with Apple Intelligence, typed or spoken, and Siri is its voice. Nothing you ask leaves the phone.

A Live Activity counts down to the next wake on the Lock Screen.

WIDGETS

APPLE WATCH

THE COACH

LIVE ACTIVITY

Copy and localization

V1 ships in English and Brazilian Portuguese and follows the device language. German, Spanish and Italian were translated and fitted, then descoped: kept for later rather than shipped without a native review.