Marek is available for hire
Hire MarekMarek Lisik
Verified Expert in Engineering
Native Mobile Developer
Location
Luxembourg City, Luxembourg
Toptal Member Since
July 12, 2021
Marek is a React Native developer with a background in native mobile development and project management. After years of programming roles and leading projects, he took a deep dive into React Native and hasn't looked back, helping clients kick off and maintain their mobile products. He has taken on large legacy codebase rewrites, built reusable libraries for core features, and created an end-to-end testing suite using React and Detox and a catalog app complete with checkout and 3D product models.
Portfolio
Forbes Media - Q.ai
JavaScript, React Native, TypeScript, Redux, Redux Toolkit, Detox, E2E Testing...
Ujet
JavaScript, TypeScript, React Native, Java, Android, Swift, Objective-C...
Netguru
JavaScript, TypeScript, React Native
Experience
Availability
Part-time
Preferred Environment
MacOS, Visual Studio Code (VS Code), TypeScript, React Native, Xcode, Git, Swift
The most amazing...
...project I've delivered was a set of proof-of-concept apps and tools for a new electric moped prototype at Ujet, a multidisciplinary, cross-platform challenge.
Work Experience
Senior React Native Developer and Front-end Team Lead
2021 - 2022
Forbes Media - Q.ai
- Led a front-end team of 3-5 developers, often working as a liaison between Product and Engineering and coordinating requirements with other technical teams.
- Prepared a strategy to improve a legacy, low-quality codebase by following modern best practices.
- Improved our unit and integration test coverage, elevating the team's ability to deliver tested and testable code.
- Rolled out one major and one minor global redesign of the mobile app, delivering a universal design system package in the process.
- Took ownership of an API gateway project in NestJS to deliver a single point of access for data required by the mobile app.
Technologies: JavaScript, React Native, TypeScript, Redux, Redux Toolkit, Detox, E2E Testing, Unit Testing, Integration Testing, NestJS, Firebase
Senior Mobile Applications Developer
2019 - 2021
Ujet
- Maintained a legacy app for the company's flagship electric two-wheeler with an ongoing effort towards better performance and modernizing the code base to use TypeScript and best practices.
- Built a SwiftUI virtual BLE peripheral (MacOS and iOS) for testing and debugging our Bluetooth services and update protocols.
- Prepared reusable in-house libraries for over-the-air and device firmware updates using BLE.
- Managed and automated continuous integration and continuous deployment using Bitbucket and Visual Studio App Center.
- Built an end-to-end testing suite using Detox, complete with a mock server to control the behavior of mocked external services during test runtime.
Technologies: JavaScript, TypeScript, React Native, Java, Android, Swift, Objective-C, Bluetooth LE, iOS, SwiftUI, MacOS
Senior React Native Developer
2018 - 2019
Netguru
- Built a large product for the hospitality industry and a white label multifunctional chat app for a car dealership that also offers maintenance services.
- Coordinated the creation of a best-practices repository to consolidate processes and infrastructure across development teams.
- Mentored new hires, prepared technology talks, and researched Flutter development.
- Participated in specification reviews, estimates, expert calls, and scoping sessions with new and potential clients.
Technologies: JavaScript, TypeScript, React Native
React Native Developer
2017 - 2018
B-MIND
- Built a small furniture catalog mobile app complete with checkout process and 3D product models.
- Rewrote a legacy app for a short-time e-moped and bike rental platform, working against a tight deadline and fixed requirements, then continued to the maintenance and expanding the feature set after launch.
- Contributed to the planning and development of new features and prepared design comps and user flows for credit card management and document uploads.
- Managed and automated the process of testing and release build distribution.
Technologies: JavaScript, React Native, Redux, Maps
IT Project Manager
2012 - 2017
Holdapp
- Consulted with clients and the development team to build up project specifications.
- Prepared detailed user stories and planned out our development efforts in Jira.
- Coordinated our project work, evaluated, and adapted on an ongoing basis.
- Organized and led daily stand-up meetings, planning sessions, retrospectives, and product demos.
- Managed resources provided for development by clients and wrote scripts to automate conversions and organization where applicable.
- Learned the basics of iOS development (Objective-C, then Swift), and became an ad hoc contributor to our codebases.
Technologies: Scrum, Agile, Continuous Deployment, Continuous Integration (CI), IT Project Management, iOS, Objective-C, Swift, UX Direction
Experience
Q.ai: AI-Powered Investing
https://tryq.aiA React Native app for managing financial investments. I was onboarded as a senior React Native developer, took ownership of the front-end source, and led the team to maintain a large legacy codebase and build new features. I'm proud of improving our TypeScript typing coverage and accuracy and bringing in utilities to help developer experience around it, elevating our unit and integration test coverage, building out a comprehensive design system based on our designers' documentation, multiple bug bashes that helped identify core issues across the front and back end as well as gaps in our understanding of the product.
Ujet Connect
http://www.ujet.comA React Native companion app for a connected, electric two-wheeler. The app allows tracking the vehicle position, sharing access with friends, unlocking and monitoring errors, access to support, and locating maintenance stations. My focus was on maintenance, clearing a large backlog of bugs, inconsistencies, and improvements, and on an ongoing rewrite to use modern React practices. I made the codebase more modular and testable, introduced TypeScript and unit and integration tests, and developed brand-new features.
Blinkee.city Moped Sharing App
https://blinkee.city/enA React Native app for short-time moped and bicycle rentals. I came in to rewrite the previous version of the app from scratch in time for the new season. As the only mobile developer, I collaborated closely with the client and the back-end team on building up requirements and guiding the project forward. We used maps to help users find their vehicles, integrated payment processing (Straal), document uploads for KYC, and robust rental state management.
Skills
Languages
TypeScript, JavaScript, Swift, Java, Objective-C
Frameworks
React Native, Redux, SwiftUI, Detox, NestJS, UIKit, Tailwind CSS
Other
English, Mobile App Development, IT Project Management, Maps, Research & Critical Thinking, UX Direction, Integration Testing, Libraries
Libraries/APIs
React, Redux-Saga, D3.js
Tools
Xcode, Git, Redux Toolkit, Plaid
Paradigms
Scrum, Agile, Continuous Deployment, Continuous Integration (CI), Test-driven Development (TDD), REST, E2E Testing, Unit Testing, Testing
Platforms
Visual Studio Code (VS Code), Bluetooth LE, iOS, MacOS, Android, Firebase
Education
2006 - 2012
Master's Degree in English
University of Wrocław - Wrocław, Poland
Collaboration That Works
How to Work with Toptal
Toptal matches you directly with global industry experts from our network in hours—not weeks or months.
1
Share your needs
Discuss your requirements and refine your scope in a call with a Toptal domain expert.
2
Choose your talent
Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.
3
Start your risk-free talent trial
Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.
Top talent is in high demand.
Start hiring