Koszalin, Poland (Remote)8+ YearsMEng, First Class - UCLEnglish · PolishStaff / Principal Engineer

Staff Mobile Engineer

Przemyslaw Szafulski

Hands-on Staff Engineer - iOS, Android, Kotlin Multiplatform, with enough backend to ship end-to-end. AI-first across discovery, architecture, and delivery.

Staff Engineer at Fanatics (1M+ MAU): tech lead on One Casino Rewards, and driving the iOS + Android to KMP + Compose Multiplatform consolidation

Tech Lead on MoneySavingExpert: 1.5M+ downloads, 4.8★, 99.9% crash-free, twice featured by Apple

Payment SDKs that unlocked a major client partnership and £1M+ in follow-on work

AI-first delivery with Claude - plan / design / implement / review, end-to-end

KMP + CMPClaude / AIiOSAndroidSystem DesignJava / Spring

About

I am a Staff Mobile Engineer with a First Class Honours MEng from University College London. My career has moved from deep native execution into hands-on Staff-level engineering - system design, cross-platform architecture, and end-to-end feature ownership across BE and mobile. Currently at Fanatics, I'm driving the consolidation of separate iOS, Android, and KMP codebases into a single Kotlin Multiplatform + Compose Multiplatform source of truth - integrated with custom CMS layers to power the next generation of iGaming experiences.

I thrive on solving complex architectural challenges - modularizing large-scale codebases with SPM, migrating legacy Objective-C to modern Swift, designing CMS-driven navigation across BE, KMP, iOS, and Android, or building serverless backends on AWS. I work AI-first with Claude end-to-end (planning, design, implementation, review) and coach my teams to do the same. Beyond the code, I am a dedicated mentor and interviewer (~50 mobile interviews this year across iOS, Android, and KMP), focused on building high-performing engineering cultures that bridge product vision and technical reality.

Experience

Staff Engineer

2025 - Present

Fanatics (via CreateFuture)

•Koszalin, Poland (Remote)

•Own features end-to-end across BE + KMP + iOS + Android - product/design discovery to system architecture to feature-flagged, A/B-tested delivery.
•AI-first delivery with Claude across planning, design, implementation, and review - coaching the wider team on skills, subagents, and workflows.
•Driving the consolidation of separate iOS, Android, and KMP codebases into a single KMP + Compose Multiplatform source of truth - porting screens and components to Jetpack Compose so both platforms share one UI implementation.
•Tech lead on One Casino Rewards (Jun - Sep 2026): a rewards system where players earn points by playing and unlock better rewards, across the iOS + Android team, the promotions backend team, and the BFF with CMS. Built most of the KMP architecture, the WebSocket layer and parts of the UI; shipped on the deadline.
•Led a flagship 4-month feature build with real-time BE to client push over WebSockets (KMP + iOS + Android) - competitor took ~18 months; ~70% user opt-in rate post-launch.
•Designed and built end to end (CMS -> BFF -> KMP client) a way for product to change app copy without an engineer or an app release, replacing strings stored as JSON in LaunchDarkly flags. Reused the existing Payload CMS for versioning and rollback; the BFF caches and localises; a KMP SDK (KSP + Koin) maps content onto typed data classes with in-code defaults. Live in production.
•Updated the guided-exit user flow: +8% active session length.
•Designed and led CMS-driven in-app navigation across BE, KMP, iOS, and Android.
•Strong delivery drove a major partnership expansion - 30+ new engineering roles opened off the back of this work.
•Joined the backend team on a tight deadline; upskilled into Java / Spring Boot, led the squad, and shipped on time.
•In parallel with the engagement, ~50 mobile technical interviews in the past year for CreateFuture across iOS, Android, and KMP - the full pipeline (technical Q&A, take-home review, pair programming, values).
•Working alongside 9 engineers across iOS, Android, and Web in the iGaming sector, on an app with 1M+ MAU.

KMP + CMPClaude / AISystem DesigniOSAndroidJava / SpringWebSockets

Senior iOS Developer

2024

Checkatrade

•Koszalin, Poland (Remote)

•Delivered a server-driven UI (SDUI), working closely with product and the backend team.
•Drove modularisation of the iOS codebase using Swift Package Manager (SPM).
•Mentored engineers transitioning from Frontend backgrounds into the mobile domain.

SwiftSPMArchitecture

SDK Author (iOS + Android)

2024

BR-DGE (via CreateFuture)

•Remote

•Independently designed and built the iOS and Android SDKs for a digital payments company (Swift / SwiftUI / Swift Concurrency / SPM, Kotlin / Compose / Retrofit).
•Won the contract after a 3-day discovery + demo - as the most expensive bid.
•Built payment integrations: 3D Secure (3DS) authentication via Braintree, plus Apple Pay and Google Pay.
•Achieved 90% code coverage and comprehensive documentation (DocC / Dokka).
•SDK secured a major partnership for the client and unlocked £1M+ in follow-on work.

SDK DesignSwiftUIModularisation

Senior Mobile Engineer, then Mobile Tech Lead

2022 - 2023

MoneySavingExpert (via CreateFuture)

•Remote

•Joined as Senior Mobile Engineer; moved into the Mobile Tech Lead role after promotion to Principal at CreateFuture (~6 months in).
•UK consumer-finance app with 500k+ MAU, 1.5M+ downloads, a 4.8★ rating, and 99.9% crash-free sessions.
•App featured by Apple twice as App of the Day.
•Migrated CI/CD from Bitrise to Codemagic - reducing costs and accelerating build times.
•Built a Flutter web app hosted on Firebase for deep-link testing.

SwiftUI/UIKitKotlin/ComposeCodemagicFirebase

iOS and Flutter Developer

2019 - 2021

BrightHR

•Manchester, UK (Remote)

•Migrated 150+ legacy Objective-C files to modern Swift, making Swift the only language in the codebase.
•Built an offline-capable enterprise Flutter app (BLoC, Sembast NoSQL) with background uploader / downloader for connectivity-poor environments.
•Established the iOS testing approach (Clean Architecture / VIP, TDD, XCUI) and built Azure Pipelines for automated deployment and testing.

SwiftFlutterAzure

Junior iOS Developer

2018 - 2019

Mapway

•Manchester, UK

•Built features for high-traffic navigation apps in Swift / Objective-C with SiriKit, MusicKit, and WatchKit; integrated RESTful services with the backend.
•Mentored a junior iOS developer in Swift / Objective-C / UIKit; automated monthly internal workflows with Python scripts.

Objective-CWatchKitPython

Personal Projects

Agent-run Personal Systems

Small systems for repeatable personal tasks, each run by Claude Code under its own rules: anything derivable is a tested script, and the model handles only judgment calls. Latest: a household budget app (backend and web front end built with Claude) on my Proxmox homelab behind Cloudflare Zero Trust. It reads bank statements, categorises payments, takes receipts from the phone, and closes each month with an approved, audited write.

Claude CodePythonFastAPISQLiteProxmoxCloudflare

OKI Investment Calculator

A live web app comparing OKI (Poland's new tax-advantaged investment account) against a standard taxable account. Models contributions, returns, Belka tax, waloryzacja, and inflation, with year-by-year chart and table. Built AI-first with Claude as a weekend project.

Next.jsTypeScriptTailwindFramer MotionClaude / AI

AI Voice Assistant for Elderly Users

An accessibility-first voice loop (voice to text to LLM to text to voice) for elderly users to ask questions and hear answers back. Python backend built AI-first with Claude (tests, separation of concerns, engineering best practice), paired with a Compose Multiplatform app shared across Android and iOS. Single talk-to-speak UI with conversation history; Firebase, no-login.

Compose MultiplatformPythonClaude / AIFirebase

MallWay Platform

Full-stack side project featuring a serverless AWS backend (HTTP API Gateway, Lambda, DynamoDB, S3, Cognito) and native iOS + Android apps for shopping-centre management. Released on both platforms simultaneously (learned Android from scratch to ship it), later rewritten from XML/UIKit to Compose/SwiftUI.

AWS LambdaSwiftUIJetpack ComposeFlutter Web

Education

MEng Electronic Engineering with Nanotechnology

2013 - 2017

University College London (UCL)

•London, UK

•First Class Honours (75%).
•Joined a research group as a summer intern; co-authored two peer-reviewed publications in quantum and optical physics.
•Presented at the 20th Slovak-Czech-Polish Optical Conference on Wave and Quantum Optics.

Mean-field and quantum fluctuation dynamics in the driven dispersive Jaynes-Cummings model - SPIE Proceedings Vol. 10142 (2016)Physical Review A 97, 033828 (2018)

Beyond the Screen

Pen & Paper RPGs

Enthusiast of tabletop role-playing games, focusing on narrative storytelling and strategic group problem-solving.

Hiking & Running

Active trail hiker and runner, finding balance and mental clarity through outdoor endurance.

Smart Home Automation

Exploring the intersection of IoT and daily life through home automation systems and hardware integration.

Get in Touch

I am currently open to Staff / Principal mobile engineering roles and high-impact, hands-on technical work. Whether you have a question or just want to connect, feel free to reach out.

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