08/31/2026 updated

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Senior iOS/Flutter Engineer

Katowice, Poland
Only remote
BSc, Computer Science
Katowice, Poland
Only remote
BSc, Computer Science

Profile attachments

Piotr_Stojanowski_Senior_iOS_Engineer_2026_v2.pdf

About me

Senior mobile developer, 14 years. iOS in Swift and SwiftUI, cross-platform in Flutter. Six years as an iOS contractor at Ford on connected-vehicle apps. I also build and run Invoice.app, live on iOS, macOS, Android and web. Remote from Poland, English, EU time zones.

GCPFlutterApple IOSApple XcodeSwiftuiIos FrameworksSwift (Programming Language)Google FirebaseDartGolang
Selected Clients
Ford (6 years, connected-vehicle iOS apps), BBC, ITV, VEON, Priority Pass, and an in-store retail platform integrated with SAP. 14 years in mobile development, mostly long-term contracts where I owned a feature area with little supervision.

iOS Development
14 years of iOS development in Swift and Objective-C, using SwiftUI, UIKit, Swift Concurrency, Core Data and Realm. Multi-platform apps for iPhone, iPad and Mac from a shared codebase, plus tvOS and macOS work.

Software Architecture
Architectural patterns including MVVM, MVVM-C, Coordinator, Clean Architecture and VIPER, with modular Swift Package Manager and dependency injection. Applied on large-scale connected-vehicle and invoicing apps.

EU E-Invoicing Compliance
Full e-invoicing implementation for two EU markets. Poland KSeF: FA(3) XML, certificate-based authentication, bidirectional sync, corrective invoices, UPO downloads, QR codes. Germany: ZUGFeRD (hybrid PDF/A plus XML) and XRechnung (EN 16931), both import and export.

Cross-Platform Development
Flutter and Dart with BLoC state management, shipped on Android and web.

Backend Development
Go on Google Cloud Run, Firebase (Auth, Firestore, Storage), REST APIs. Migrated a legacy on-prem logging service to Cloud Run. Subscription and billing infrastructure with RevenueCat.

Testing
XCTest, XCUITest, snapshot testing and protocol-oriented mocking.

Tooling and CI/CD
Xcode, Swift Package Manager, CocoaPods, fastlane, GitHub Actions, Jenkins, TestFlight, SwiftLint, Instruments, Crashlytics.

Product Ownership
I build and run Invoice.app, a live invoicing product on iOS, iPadOS, macOS, Android and web with around 500 paying subscribers. I wrote every part of it, and I handle store releases, ads, pricing and support. So I know what a feature costs after it ships, not only before.

Technical Leadership
Code review, pair programming, design reviews, and mentoring mid-level iOS engineers.

Contracting
Polish sole proprietorship, VAT-EU registered, reverse charge for EU B2B clients. Remote, EU time zones, working in English.

Experience

Professional experience10+ years
Freelancer since2016

Languages

EnglishFluentPolishNative speaker

Project history

Founder & Software Engineer

Invoice.app

Banking & Financial Services

< 10 team member

Invoicing product for freelancers and small businesses, live on iOS, iPadOS, macOS, Android and web with around 500 paying subscribers. Built the whole stack: Swift and SwiftUI across iPhone, iPad and Mac, Flutter with BLoC for Android and web, Go backend on Cloud Run with Firestore and Firebase, and RevenueCat for subscriptions. Implemented EU e-invoicing compliance for Poland (KSeF, FA(3) XML, certificate authentication, corrective invoices, UPO, QR codes) and Germany (ZUGFeRD hybrid PDF/A, XRechnung per EN 16931), import and export. Also handle store releases, ASO, paid acquisition and support. Started alongside contract work in 2019, full time from January 2026.

Senior iOS Developer

Ford Motor Company

Automotive & Vehicle Manufacturing

>10.000 team member

Six-year contract in a 10-person iOS team building Ford's connected-vehicle apps for fleet customers across the UK, EU and US. On FordPass Pro, delivered EV features and worked in a pair-programming, fully tested codebase. On Ford Pro Telematics Drive, refactored the notifications module including legacy code and UI, added support for new notification types, built new UI components and worked with push notifications. Ran an incremental Objective-C to Swift migration alongside feature work. Migrated an internal Python logging converter (Dynatrace to Splunk) from an on-prem platform to Google Cloud Run. Code review and mentoring of mid-level engineers.

Senior iOS Developer

Tigerspike, Smarter

500-1000 team member

Two short contracts. At Tigerspike, worked on Priority Pass, refactoring and improving the lounge search mechanism plus unit and UI tests. At Smarter, improved the live view streaming mechanism in the Smarter 3.0 app for FridgeCam connected kitchen devices.

iOS Developer

TVPlayer

Media & Publishing

10-50 team member

Live TV and catch-up streaming service for the UK market. Rewrote in-app purchases to support multiple auto-renewable subscriptions with introductory pricing. Implemented new designs for login, registration and subscription screens. Bug fixing and performance work.

iOS Developer

Ostmodern (second contract)

50-250 team member

BBC Player, the BBC's SVOD app. Implemented deep linking with Branch.io, Google Analytics tracking, iPhone X support, and integration with Auth Broker, the BBC's authentication provider. Bug fixing and performance improvements.

iOS Developer

VEON

1000-5000 team member

Multi-platform messaging app with VoIP calling, rich media messaging and a built-in content feed for news, articles and music. Refactored existing code to VIPER architecture and migrated legacy Objective-C to Swift.

iOS Developer

Keytree

50-250 team member

KIT, an in-store retail app for store associates covering product and stock lookup, purchase history, internal messaging, tasks and appointments. Built to be white-labelled per retail client; my engagement covered the Burberry integration. Modular architecture with CocoaPods per module, integrated with SAP systems.

iOS Developer

yumXYZ

Other

< 10 team member

Platform letting food traders run an online shop while customers discover, order and pay. Built two iOS apps sharing code through a dynamic framework, the Firebase backend (realtime database, storage, cloud functions, auth, push notifications), Stripe payment integration, and a Django admin panel.

Lead iOS Developer

Made by Fire

< 10 team member

NURVV, a fitness app for professional runners. The app paired over Bluetooth with an in-shoe sensor collecting temperature, foot strike, acceleration, pronation, distance and step data. Rewrote core components including the Bluetooth and backend communication layers, built custom UI components, set up Jenkins and fastlane, and oversaw junior team members.

iOS Developer

Ostmodern

50-250 team member

Eleven months across two streaming products. On BBC Player, built a video player from scratch for streaming and integrated BuyDRM's KeyOS framework for offline downloads, plus custom UI components, tracking and analytics libraries, and performance work. On Olympic Channel, built a video player component with JWPlayer, animations with AsyncDisplayKit, custom UI modules, and integration with the Skylark backend platform.

Personal Project

BLACK - B&W Film Emulator

Internet & IT

< 10 team member

Photo app emulating real black and white film stocks, built with a designer. Windows Phone first, then iOS. Wrote both apps: on Windows Phone, most UI controls built from scratch with image processing via the Lumia Imaging SDK and WriteableBitmapEx; on iOS, GPUImage for processing plus in-app purchases and Crashlytics. One of the first App Store apps to apply effects to Live Photos, implemented before Apple published an API. Over 1M downloads, 150k in the first three months on iOS, featured repeatedly by Apple. No longer maintained.

iOS Application Developer

Candyspace

50-250 team member

Eighteen months across three projects. On ITV Hub, worked on the app redesign with complex custom UI components, third-party tracking and analytics, legacy code updates, and 64-bit and iOS 8 SDK support. Built a tvOS prototype of ITV Hub. For Burberry Scarves, an interactive Christmas installation on The Curve at Piccadilly Circus, built the native OS X application communicating with a Node.js server over WebSockets, handling instant PNG sequence playback, simultaneous multi-file video downloads and game state transitions.

iOS Developer, then Senior Mobile Developer

Grupa SPOT, FUN and MOBILE, Ubinow, Work Club
Early career across four companies; Ubinow was acquired by Work Club during my time there. Built Rated People's Find Work app from the ground up, which became the basis for their subsequent iOS development. Built an iBeacon and Bluetooth LE SDK for Desire, a proximity shopping assistant. Braintree payments for GrubClub. Also built .NET Web API backend services on Azure for WLcompanion with an ASP.NET MVC admin panel, and earlier Cocos2d games and Core Animation work. Sole iOS developer on most projects and mentored junior team members.

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