Marcin Szeptun
@marcinszeptun
Senior Android developer focused on performant, secure, user-centered mobile apps.
What I'm looking for
I am a Senior Android developer with extensive experience building and owning features for high‑scale consumer and fintech mobile applications. I have led Android projects, introduced Jetpack Compose, and driven architecture improvements while mentoring teammates to raise code quality.
At companies from startups to large teams I delivered secure wallet and payment solutions, video upload features using AWS, onboarding optimizations, and migrated apps from Java/MVP to Kotlin and modern architectures. I prioritize testing, performance, and maintainable architecture including MVVM/MVI, Clean Architecture, and DI with Dagger/Hilt/Koin.
I bring strong cross‑functional collaboration with backend, iOS, design and product teams, a growth mindset, and a focus on measurable user outcomes such as conversion, stability, and efficiency.
Experience
Work history, roles, and key accomplishments
Senior Android Developer
Housecall Pro
Sep 2024 - Present (1 year 1 month)
Develop and own finance-related features in the Housecall Pro Android app, manage releases and user feedback, and implemented a partial large video upload using an AWS solution to improve media handling.
Senior Android Developer
Vero
Aug 2022 - Jul 2024 (1 year 11 months)
Owned multiple Android features for a social app used by millions, introduced Jetpack Compose and best practices, and mentored developers to improve code quality and performance of image loading.
Android Developer
BlockFi
May 2021 - Aug 2022 (1 year 3 months)
Worked on the BlockFi Wallet onboarding feature to increase registration conversion, refactored the Android codebase toward Clean Architecture, and created a Compose-based design system.
Android Developer, Project Leader
PayEye
Jun 2020 - May 2021 (11 months)
Led Android development for PayEye Wallet, designed secure app architecture, implemented secure storage and anti-tamper measures, and built custom views and notification integration with POS terminals.
Android Developer
Ryanair
Jul 2018 - Jul 2020 (2 years)
Migrated Ryanair Discovery Android app from Java/MVP to Kotlin and MVVM/MVI, implemented unit and UI tests, enabled Instant App support, and worked on analytics and A/B testing to optimize user experience.
Education
Degrees, certifications, and relevant coursework
Wroclaw University of Science and Technology
Master Degree, Computer Science (Software Engineering)
2019 - 2020
Completed a Master Degree in Computer Science with a specialty in Software Engineering between February 2019 and July 2020.
Wroclaw University of Science and Technology
Bachelor Degree, Computer Science
2015 - 2019
Completed a Bachelor Degree in Computer Science from October 2015 to January 2019.
Availability
Location
Authorized to work in
Job categories
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