Oskar Ryszard Kosciuk

OSKAR RYSZARD KOSCIUK Senior Mobile Developer - - https://www.linkedin.com/in/kosciuk-oskar-rostik-1a-/ https://oskar-zeta.vercel.app Warsaw, Poland Summary Sr, Mobile Developer A Mobile Developer with 8 years of dedicated experience, professional well- versed in crafting robust and user-centric mobile applications for both iOS and Android platforms. Experienced Flutter Developer with proven record of developing and maintaining cross-platform mobile applications that increased app performance by 25% for over many clients. Expert in implementing state management solutions and optimizing app performance, resulting in 40% reduction in load times. Skilled in collaborating with UI/UX designers to deliver responsive and user-friendly mobile interfaces, enhancing user engagement by 30%. Adept at leveraging both hard and soft skills to achieve significant project outcomes and improve client satisfaction Skills Flutter Android Java BPM Firebase Ios Swift Javascript Typescript JIRA Kotlin Mongodb Mysql Next.js Node Node.js React Native Redux Restful Restful Apis Agile Agile Methodologies Statistics Team Leadership Trello Material UI Figma SASS UI/UX Experience Ecovita Sr. Mobile Developer, Ecovita Warsaw, Poland 10/2020 • Developed and maintained React Native applications for iOS and Android, achieving a 20% increase in user retention • Architected a comprehensive article management solution, seamlessly integrating four critical third-party APIs and significantly improving backend performance metrics, with server response times reduced to an average of under 200ms per request • Led a team of four developers, implementing Agile methodologies that facilitated the delivery of five major project releases, resulting in a 30% improvement in project completion rates • Structured reusable UI components according to custom design specifications to optimize coding efficiency and uphold high-quality standards throughout the project lifecycle, which contributed to a 20% reduction in bug count • Thoroughly tested and debugged all React Native components prior to deployment, ensuring projects met all functional requirements within stipulated timelines, and achieving an average customer satisfaction rating of 85% for projects completed during tenure Riddep Mobile Engineer Warsaw 09/2018 - 09/2020 • Devised and developed Riddep, a fully-featured social media platform, authoring over 150,000 lines of code for web, Android, and iOS applications • Engineered a scalable system that encompassed all major functionalities of existing social media platforms, built entirely from scratch • Championed the development team as Team Leader, ensuring project milestones were consistently met while maintaining high code quality standards • Monitored user statistics for steps and distances traveled daily, weekly, and monthly • Served as the main developer responsible for implementing most features of the application based on Figma designs • Managed synchronization of data steps to the backend through both manual and scheduled sync methods • Conceptualized a group chat feature to enable members to communicate and share memories effectively • Scrutinized and resolved bugs post-release • Collaborated with the Business Process Manager (BPM) to estimate tasks and troubleshoot issues • Functioned as the Sole Android Developer for both applications • Developed new application features in line with UI design specifications Veloxity Software Engineer York, pennsylvania, United States 10/2016 - 08/2018 • Engineered the Veloxity SDK for Android, React Native, and Unity platforms, now functioning on over 5 million monthly active devices • Maintained and enhanced Blinnk, an online platform utilizing React to assist clients in targeting consumers based on their behavior, offering real-time advertisements • Provided comprehensive support for clients during analysis, implementation, and testing phases • Refactored and developed Android tools utilized by over 1 million devices, achieving a remarkable crash-free rate of 99.98% over the past 100 implementations Education AGH University of Science and Technology Cracow Bachelor of Science, Information Technology 02/2011 - 07/2016 • During my Bachelor of Computer Engineering program, I gained a solid foundation in computer science principles and engineering practices. Through coursework and hands-on projects, I developed proficiency in programming languages, software development, hardware design, and system analysis. This program equipped me with a deep understanding of the interplay between software and hardware components, enabling me to approach technical challenges with a holistic perspective. Languages English Advanced Polish Native