I'm an iOS developer enthusiast about making technology faster and easier through mobile apps. I helped scale the Moje O2 app to nearly 1 million users, boosted item swapping by 10% in the award-winning Paperclip app, and transitioned legacy apps from Objective-C to SwiftUI, like Tickaroo's Kicker app. Most recently, I've revitalised the jö App at REWE, where I redesigned the login and registration flow to improve onboarding for new customers. My expertise includes Swift, SwiftUI, UIKit, Combine and more. I focus on performance optimization, clean and testable code, memory management, and mastering new tech like Kotlin Multiplatform to build seamless, high-performing apps.…

hajducakmarek

I'm an iOS developer enthusiast about making technology faster and easier through mobile apps. I helped scale the Moje O2 app to nearly 1 million users, boosted item swapping by 10% in the award-winning Paperclip app, and transitioned legacy apps from Objective-C to SwiftUI, like Tickaroo's Kicker app. Most recently, I've revitalised the jö App at REWE, where I redesigned the login and registration flow to improve onboarding for new customers. My expertise includes Swift, SwiftUI, UIKit, Combine and more. I focus on performance optimization, clean and testable code, memory management, and mastering new tech like Kotlin Multiplatform to build seamless, high-performing apps.…

Available to hire

I’m an iOS developer enthusiast about making technology faster and easier through mobile apps. I helped scale the Moje O2 app to nearly 1 million users, boosted item swapping by 10% in the award-winning Paperclip app, and transitioned legacy apps from Objective-C to SwiftUI, like Tickaroo’s Kicker app. Most recently, I’ve revitalised the jö App at REWE, where I redesigned the login and registration flow to improve onboarding for new customers.

My expertise includes Swift, SwiftUI, UIKit, Combine and more. I focus on performance optimization, clean and testable code, memory management, and mastering new tech like Kotlin Multiplatform to build seamless, high-performing apps.

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Experience Level

Expert
Intermediate

Language

Slovak
Fluent
English
Advanced

Work Experience

iOS Developer at Qest automa Kon, Prague
February 1, 2029 - September 23, 2025
Junior iOS Developer; used Firebase and Firestore; worked with senior developers to gain experience in app architecture and backend integration.
iOS Developer at Qest Automation (Qest automa Kon), Prague
February 1, 2029 - September 23, 2025
Contributed to mobile apps using Firebase and Firestore; developed understanding of app architecture and backend integration while gaining exposure to Objective‑C and Swift; contributed to ongoing improvements.
iOS Developer at Qest automa Kon
February 1, 2029 - September 23, 2025
Junior iOS Developer; contributed to iOS apps using Firebase and Firestore. Gained experience in app architecture and backend integration while developing with modern iOS technologies.
iOS Developer at REWE Group
October 1, 2025 - September 23, 2025
Contributed to modernising the jö App, focusing on enhancing user experience and updating legacy technologies. Implemented a completely new login and registration flow to simplify authentication and subscription management, introducing Combine and SwiftUI to the codebase.
iOS Developer at REWE Group
October 1, 2025 - September 23, 2025
Contributed to revitalising the jö App by completely redesigning the login and registration flow, significantly improving onboarding and subscription management UX. Introduced modern technologies including Combine and SwiftUI to the existing codebase, enabling a more maintainable and performant app. Collaborated with an exceptional cross-functional team to elevate the product and customer experience.
iOS Developer at REWE Group
October 1, 2025 - September 23, 2025
Contributed to modernising the jö App, focusing on enhancing user experience and updating legacy technologies. Implemented a completely new login and registration flow to simplify authentication and subscription management. Introduced Combine and SwiftUI to the existing codebase.
iOS Developer at O2 Czech Republic
February 28, 2025 - September 23, 2025
Led development of the Moje O2 app, driving user growth from 400k to near 1 million users. Focused on SwiftUI, VIPER, and Combine; implemented unit tests; explored Kotlin Multiplatform to broaden cross‑platform capabilities.
iOS Developer at O2 Czech Republic
February 1, 2025 - September 23, 2025
Key role in developing the Moje O2 app, growing user base from 400,000 to nearly 1 million. Worked with SwiftUI, VIPER, Combine and implemented Unit tests. Explored Kotlin Multiplatform in recent months.
iOS Developer at O2 Czech Republic
February 1, 2025 - September 23, 2025
Played a key role in developing the Moje O2 app, driving user growth from 400k to nearly 1 million. Worked mainly with SwiftUI, VIPER architecture, Combine and unit tests. In the last six months, explored Kotlin Multiplatform.
Lead iOS Developer & Founder at Youte s.r.o
January 31, 2022 - September 23, 2025
Led the development of an innovative platform connecting people through real-world adventures. Managed a team, selected technologies for mobile and web platforms, and built an app that fosters meaningful connections. Developed leadership, communication, and startup management skills, including handling legal and business aspects.
Lead iOS and Founder at Youte s.r.o
January 1, 2022 - September 23, 2025
Led development of an innovative platform connecting people through real-world adventures. Managed a team, selected technologies for mobile and web platforms, and built an app that fosters meaningful connections.
Lead iOS and Founder at Youtes s.r.o
January 1, 2022 - September 23, 2025
Led the development of an innovative platform connecting people through real-world adventures. Managed a team, selected technologies for mobile and web platforms, and created an app that fosters deep connections. Developed leadership, communication, and startup management skills, including handling legal and business aspects.
iOS Developer at Paperclip, Remote
September 30, 2021 - September 23, 2025
Contributed to an award-winning marketplace app, boosting item swapping among universities by 10%. Embraced reactive programming approaches and MVVM, and adopted new UI frameworks to enhance performance and streamline development.
iOS Developer at Paperclip
September 1, 2021 - September 23, 2025
Contributed to an award-winning marketplace app; helped increase item swapping by 10% across universities. Adopted reactive programming and MVVM; used Stevia and new UI frameworks to optimize performance.
iOS Developer at Garwan Consul Kng, Bratislava
September 1, 2021 - September 23, 2025
Contributed to rewriting Tickaroo's Kicker app from Objective-C to SwiftUI, achieving a 15% increase in users through optimization and adopting new technologies. Gained experience with Objective-C while diving into Swift Concurrency and debugging.
iOS Developer at Garwan Consul Kng, Bratislava
September 1, 2021 - September 23, 2025
Rewrote Tickaroo’s Kicker app from Objective‑C to SwiftUI, leveraging modern concurrency to improve performance and user engagement by about 15%. Gained hands-on experience with Objective‑C while diving into Swift Concurrency and advanced debugging.
iOS Developer at Paperclip
September 1, 2021 - September 23, 2025
Contributed to an award-winning marketplace app, helping users buy, sell, and swap items. Played a role in increasing item swapping by 10% and adopting reactive programming (Bond, ReactiveKit, Moya), MVVM, and UI frameworks like Stevia to optimize performance and development flow.
iOS Developer at Garwan Consul Kng
September 1, 2021 - September 23, 2025
Contributed to rewriting Tickaroo's Kicker app from Objective-C to SwiftUI, achieving a 15% increase in users through optimization and leveraging new technologies. Gained hands-on experience with Objective-C while diving into Swift Concurrency and debugging.
iOS Developer at Touch4IT
May 31, 2020 - September 23, 2025
Freelance project developing an educational social platform (white-label app); worked with VIPER architecture, modular development, SDK creation, Core Data, and SwiftData to deliver scalable and reusable iOS solutions.
iOS Developer at Touch4IT
May 1, 2020 - September 23, 2025
Freelance project developing an educational social platform with VIPER architecture, modular development, SDK creation, Core Data and SwiftData.
iOS Developer at Touch4IT
May 1, 2020 - September 23, 2025
Freelance project for an educational social platform. Worked with VIPER architecture, modular development, SDK creation, Core Data, and SwiftData to build scalable and reusable iOS solutions.
iOS Developer at Payout, Žilina
February 29, 2020 - September 23, 2025
Worked on multiple iOS projects including safety and financial apps; used VIPER, MVVM and SwiftUI (from its 1.0 version). Improved UI testing, unit testing, dependency management and memory management.
iOS Developer at Payout
February 1, 2020 - September 23, 2025
Worked on multiple iOS projects including safety and financial apps using VIPER, MVVM and SwiftUI (1.0). Improved UI testing, unit testing, dependency management and memory management.
iOS Developer at Payout
February 1, 2020 - September 23, 2025
Worked on multiple iOS projects, including safety and financial apps, using VIPER, MVVM, and SwiftUI. Improved UI testing, unit testing, dependency management, and iOS memory management.

Education

Bachelor's degree at University of Žilina
September 1, 2016 - September 1, 2021
Trainee at Azet Academy
July 1, 2017 - September 30, 2017
High School Diploma at Gymnázium Hlinská
January 1, 2011 - December 31, 2015
Bachelor's degree at University of Žilina
September 1, 2016 - September 1, 2021
Trainee at Azet Academy
July 1, 2017 - September 1, 2017
Graduated in general field at Gymnázium Hlinská
January 1, 2011 - December 1, 2015
Bachelor's degree at University of Žilina
September 1, 2016 - September 1, 2021
General secondary education at Gymnázium Hlinská
January 1, 2011 - December 1, 2015
Trainee at Azet Academy
July 1, 2017 - September 1, 2017

Qualifications

Trainee
July 1, 2017 - September 1, 2017

Industry Experience

Software & Internet, Retail, Education, Professional Services, Media & Entertainment, Telecommunications