Now boarding Turku · Finland Service IOS-01

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WILLIAM PERTSON

IC iOS iOS Developer via Swift · SwiftUI · UIKit

I build native iPhone and iPad apps that run like a well-kept timetable: fast to launch, smooth at 120 Hz, accessible to every passenger and dependable release after release. Eight years of shipping Swift code for health, mobility and retail products, from first prototype to App Store.

8Years on line

23Apps shipped

4.8★Avg. rating

99.9%Crash-free

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ANNOUNCEMENT

Passenger information · Profile of the service

◆ Attention please

William Pertson is an iOS Developer based in Turku, Finland, specialising in native Apple-platform engineering with Swift and SwiftUI. He has spent the last eight years building products people open every day: patient companion apps, mobility tickets, point-of-sale tools and reading apps used by hundreds of thousands of people.

His approach borrows from good railway operations: clear architecture, predictable releases and nothing left to chance. He cares about modular codebases, careful performance profiling in Instruments, thorough test coverage and accessibility that is designed in from the start, not added at the end.

He works closely with designers and backend teams, mentors junior developers, and feels as comfortable maintaining a ten-year-old UIKit codebase as starting a new SwiftUI app.

ServiceiOS Developer
DepotTurku, Finland
GaugeSwift 6 · SwiftUI · UIKit
TargetsiPhone · iPad · Apple Watch
LanguagesEnglish · Finnish
Status● Boarding new projects

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DEPARTURES

Career timetable · Select a departure for calling points

Leads a team of five iOS engineers building a patient companion app for three Nordic hospital districts.
Migrated a 140k-line UIKit app to a modular SwiftUI architecture with 32 Swift packages.
Cut cold-launch time from 2.4 s to 0.9 s and brought the crash-free rate to 99.9%.
Introduced Xcode Cloud pipelines and snapshot testing, moving from monthly to weekly releases.

Built the mobile ticketing and journey planner app for a regional ferry and bus operator.
Implemented Apple Pay checkout and Wallet passes, used for more than 1.2 million tickets a year.
Designed an offline-first sync layer on Core Data for reliable use on the archipelago routes.
Shipped Live Activities and widgets showing real-time departure updates.

Delivered eleven client apps for retail, media and event customers at an agency.
Gradually rewrote legacy Objective-C modules in Swift and set up Fastlane release automation.
Worked with designers to turn Figma prototypes into accessible, pixel-accurate interfaces.

Specialised in software engineering and human–computer interaction.
Thesis: "Energy-aware background processing on mobile devices".
Published a first indie app, a campus transit timetable, which reached 6,000 student users.

All times local · Year format HH:MM = 20YYInformation subject to change

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ROUTES

Selected projects · From origin to App Store terminus

R1Consumer · iPhone & Watch

Tidewatch

Marine weather for the archipelago

Duration 7 months
Role Lead iOS
Passengers 48k MAU

A sailing and marine-forecast app that combines wind, wave and sea-level data with offline charts of the Finnish archipelago. Watch complications show gusts at a glance, and Live Activities warn about changing conditions.

SwiftUI
WeatherKit
MapKit offline
WidgetKit
App Store

Featured · Nordic App Store4.8★ · 2.1k ratings

R2Health · iPhone

Pulse Ledger

Patient companion for chronic care

Duration Ongoing
Role Senior iOS
Passengers 120k patients

A medical-grade companion app that syncs HealthKit data, schedules medication reminders and securely shares readings with care teams. It was built to satisfy strict privacy and medical-device documentation requirements.

Modular SPM
HealthKit
CryptoKit
Snapshot tests
Weekly release

99.9% crash-free0.9 s cold launch

R3Mobility · iPhone

Lautta Pass

Ferry & bus ticketing, offline-first

Duration 2 years
Role iOS Developer
Passengers 1.2M tickets/yr

A ticketing and journey-planning app for island routes with unreliable mobile coverage. Tickets are validated offline with signed Wallet passes, and Live Activities follow the ferry from pier to pier.

UIKit + Combine
Core Data sync
Apple Pay
Live Activities
App Store

−38% support ticketsPassKit · ActivityKit

R4Open source · iPad

Lumo Reader

Accessibility-first reading app

Duration Side project
Role Author
Passengers 1.4k GitHub ★

An open-source EPUB reader designed for low-vision and dyslexic readers, with full VoiceOver support, Dynamic Type up to AX5, adjustable letter spacing and a reading ruler. Its accessibility components are published as a reusable Swift package.

SwiftData
VoiceOver
Dynamic Type
Swift Package
GitHub

Open source · MITWCAG 2.2 AA

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ROLLING STOCK

Skills & tooling · Train composition

Locomotive

Languages & UI

SwiftSwift 6, strict concurrency, generics, macros
SwiftUICustom layouts, animations, Observation
UIKitCompositional layout, diffable data sources
Objective-CLegacy maintenance & interop

Carriages

Frameworks

Concurrency & Combineasync/await, actors, AsyncSequence
SwiftData · Core DataOffline-first sync, migrations
HealthKit · MapKitWeatherKit, CoreLocation, PassKit
WidgetKit · ActivityKitWidgets, Live Activities, App Intents

Signalling

Quality & delivery

XCTest · Swift TestingUnit, UI and snapshot testing
CI/CDXcode Cloud, Fastlane, GitHub Actions
InstrumentsTime Profiler, memory, hitches
AccessibilityVoiceOver, Dynamic Type, WCAG

Composition: shunting regional intercity / expert

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INFORMATION

Contact desk · Reservations for new projects

Contact ticket
Valid anytime · All zones 1st

William Pertson

iOS Developer

First name: William
Surname: Pertson
Address: Karjakuja 8
20540 Turku
Finland
Phone: +1 650 307 2214
Email: jennellmooneyham@gmail.com

Send an emailjennellmooneyham@gmail.com Call the desk+1 650 307 2214

Now accepting reservations: freelance iOS projects, contract roles and full-time positions, on site in Turku or remote across the EU. Usual reply time is one working day.