Mikołaj Wilczek

Principal Mobile Developer | Expert in Native & Hybrid (React Native, Capacitor/Ionic)


Summary

Principal Mobile Engineer with 10+ years delivering high-impact native & hybrid apps (Swift, Kotlin, React Native, Capacitor/Ionic) across HR, logistics, IoT, fintech and retail domains. I architect unified mobile platforms, accelerate performance (e.g. 50% cold start improvement), and scale usage (e.g. 3x active user growth) while reducing technical debt and dependency risk via custom native bridges. Comfortable reviving legacy codebases and shaping greenfield strategy. Hands-on across mobile CI/CD, offline architectures, BLE/IoT integrations, and developer enablement. Build side projects in Node.js & Python on AWS/GCP and prototype hardware / 3D printed solutions to explore product feasibility.


Experience

Principal mobile developer

Tellent | - Present

HR application

Lead conversion of existing React web application into a performant, unified native mobile experience.

Impact:Design and implement mobile architecture; coordinate cross-team collaboration & workflow optimization; lead development of critical platform capabilities; convert existing web applications to native with minimal code changes/resources; architect unified mobile platform integrating multiple web apps into a cohesive experience.

Tech stack:React, Capacitor, Node.js, Elixir

Senior mobile developer

Tellent (formerly Recruitee) | -

Companion App for Applicant Tracking System

Mobile app focused on quick, frequent operations on the go. Team: 5 (sub-team) within 40+ engineering org

Impact:Owned mobile & PWA lifecycle (development, deployment, monitoring, infrastructure); tripled user base and increased product awareness/independence; improved cold startup performance by 50%; developed custom native plugins reducing external dependency risk; removed technical debt enabling faster delivery; researched user needs and organized backlog flow.

Tech stack:Angular, Ionic, Capacitor, Android (Kotlin), iOS (Swift), Elixir

React Native and React developer

Monterail (Software house) | -

Luxury Fashion Browsing App

Fashion browser tailored for luxury fashion retail companies. Team: 4

Impact:Developed and deployed apps; produced rapid prototypes & PoCs validating UX/features; advised stakeholders on technical limitations and performance trade-offs; leveraged latest stack to accelerate iteration speed.

Tech stack:Redux, Expo, React Native, React, Airtable, Firebase technologies, Android (Java), iOS (Objective-C)

Fintech + HR Application

Hybrid application for customer experimental wage-related processes

Impact:Implemented & deployed hybrid app (iOS & Android); shipped supporting website improvements; navigated tight deadlines while maintaining quality; improved customer communication loops; balanced scope with team capacity to meet milestones.

Tech stack:Expo, Ruby on Rails, Postgres, Android (Java), iOS (Objective-C)

Multiplatform Business Communication App

Business communication across smartphones & PCs. Team: 6, Scrum

Impact:Implemented multi-platform communication client (mobile & web) using early-stage libraries; engineered shared components minimizing platform divergence; deployed and maintained apps across targets; overcame tooling immaturity

Tech stack:React Native for Web, NodeJS, Postgres, GraphQL, Android (Java), iOS (Objective-C)

Parking App for Shopping Malls

Seamless, ticketless parking experience for shopping mall visitors. Team: 4, Kanban

Impact:Developed web & mobile ticketless parking solution; reconstructed missing documentation; collaborated with cross-continental stakeholders on roadmap; delivered core feature set within very limited budget while maintaining usability.

Tech stack: Redux, React Native, React, NodeJS, MongoDB, GitHub, Git, Android (Java), iOS (Objective-C)

Mobile Game - Charity Encouragement

Simple game promoting charitable contributions. Team: 3, Waterfall

Impact:Consulted & mentored team on React Native and store compliance; mitigated framework constraints to reach acceptable performance; pushed React Native to its limits for game interactions.

Tech stack:React Native, Android (Java), iOS (Objective-C)

IoT and Android developer (R&D Specialist on Grant Project)

Wrocław University of Science and Technology | -

Heat Detection in Cows

Project aimed at improving cow health and milk production by gathering and analyzing data from cow collars. Team: 6 (incl. 4 lecturers)

Impact:Conducted hardware testing & Android development for BLE livestock collars; deployed and programmed devices; built auxiliary data-gathering software; mediated between research requirements and hardware constraints; resolved connectivity issues in metal barns; implemented algorithms and produced comprehensive research documentation.

Tech stack:Android (Java), Bluetooth 4.2/5, R, Python, C++, BLE scanning libraries, nRF51/52 dev kit, Redmine

Mobile developer (Android & iOS)

Human Device (Software house) | -

Multi-domain mobile solutions

Delivered Android & iOS applications across logistics (fleet & cargo), on-demand food delivery, renewable energy device management, and offline retail inventory. Transitioned from Android focus into full bi-platform ownership, including CI/CD and mentoring.

Impact:Owned end-to-end mobile delivery (architecture, features, releases); integrated peripherals (barcode scanners, printers); maintained CI/CD; mentored and onboarded developers; implemented accessibility improvements; built custom ORM & caching layer for offline search & faster iteration; coordinated cross-platform feature parity; delivered renewable energy management suite; established reliable peripheral & offline communication workflows.

Tech stack:Android (Java/Kotlin), iOS (Swift), Google Maps API, Retrofit, Alamofire, BLE / peripheral comms, Java EE, Spring, PHP, Git/Subversion, CI/CD tooling


Education

Master's degree (2018)

Wrocław University of Science and Technology, faculty of Computer Science and Management - information system design

Bachelor's degree (2017)

Wrocław University of Science and Technology, faculty of Electronics - software engineering

Notable skills

Polish (Native) English (C1) German (A1) Oracle Certified Java Programmer IoT DevOps Cloud Python Engineering and organizational skills