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Aleksandar S.
Senior Software Engineer
Aleksandar is a Senior Software and Mobile Engineer with over 14 years of experience, specializing in developing native and cross-platform mobile applications using Android, iOS, and Flutter. He combines deep technical expertise with leadership and mentoring skills to help teams deliver stable, scalable, and user-focused mobile products.
He has collaborated with global brands such as Coca-Cola, Nike, Deloitte, and Johnson & Johnson through both independent projects and consulting engagements. At Circle Medical, he led Android and iOS teams, implemented CI/CD automation, and boosted mobile performance by 300%.
Aleksandar is recognized for creating efficient development processes, maintaining high-quality codebases, and empowering teams to achieve and exceed their goals, consistently delivering impactful and reliable mobile solutions.
Main expertise
- Flutter 5 years

- Dart 5 years

- Android 15 years

Other skills
- Google Maps 9 years

- Mocha.js 2 years

- Zustand 2 years
Selected experience
Employment
Mobile Tech Lead
Circle Medical Technologies - 3 years 4 months
Circle Medical is a Y Combinator–backed telemedicine company providing primary care and mental health services via mobile and web platforms.
- Led Android and iOS teams, driving product delivery and maintaining alignment between engineering, design, and business goals.
- Implemented technical roadmaps, coding standards, and architecture guidelines, improving code quality and reducing technical debt.
- Managed the hiring and onboarding of over 15 engineers, growing the mobile team by 300% and introducing scalable agile processes.
- Designed test automation frameworks and continuous integration pipelines, increasing release frequency while maintaining HIPAA compliance.
- Partnered with executives and stakeholders to align engineering KPIs with OKRs, balancing product speed and long-term maintainability.
Technologies:
- Technologies:
Android
Swift
Kotlin
Firebase
MVVM
Agile
REST API
- Team Leading
Android Jetpack
Senior Android Engineer
Konstrukt - 10 months
A healthcare software startup focused on building mobile tools to help doctors accurately calculate pediatric medication doses.
-
Developed both Android and iOS native applications, ensuring accuracy, reliability, and medical safety.
-
Designed and implemented a precise dosage calculation system, minimizing input errors.
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Collaborated with medical consultants and product teams to align design and data validation.
-
Participated in developer hiring and conducted technical interviews.
Technologies:
- Technologies:
Android
iOS
Swift
Kotlin
REST API
SwiftUI
Android Jetpack
Android NDK
-
Co-Founder & Platform Lead
Meeliana - 1 year 5 months
Meeliana is an IoT startup developing a property automation platform for residential and commercial buildings, integrating smart sensors for monitoring and control. The project was part of the Raising Starts Accelerator and showcased at Expo Dubai 2020.
- Co-founded the company, defining the product vision, roadmap, and long-term strategy.
- Led the architecture design and development of the IoT platform, integrating cloud-based automation and analytics.
- Built a scalable API infrastructure and communication layer between IoT devices, mobile apps, and backend services.
- Defined project milestones, led a cross-functional engineering team, and ensured the timely delivery of new features.
- Represented Meeliana at industry events, investor meetings, and accelerator programs, securing early-stage funding.
Technologies:
- Technologies:
AWS
Android
Kotlin
REST API
- MQTT
- Internet of Things (IoT)
BLE
Senior Mobile Engineer
MindTrust Labs - 7 years
MindTrust Labs is a US-based digital consultancy delivering AI-driven, web, and mobile solutions to startups and global enterprises. The company helps clients transform ideas into scalable digital products through innovative design and modern engineering practices.
- Led the end-to-end development of seven mobile applications across fitness, healthcare, and finance sectors, focusing on performance, usability, and maintainability.
- Designed and implemented Flutter applications using BLoC for state management, integrating REST APIs, Firebase, and WebRTC for real-time communication and multimedia processing.
- Developed and maintained CI/CD pipelines using GitHub Actions, enabling automated builds, testing, and deployments, and reducing release time by 35%.
- Conducted performance profiling and optimization on both Android and iOS, improving app startup times and reducing memory usage.
Technologies:
- Technologies:
AWS
Flutter
Android
iOS
Swift
Firebase
Dart
REST API
WebRTC
Bloc
SwiftUI
GitHub Actions
Community Leadership & Public Speaking
Niš Tech Community - 1 year 9 months
-
Organized meetups, workshops, and conferences for regional developer communities.
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Delivered public talks on mobile development, freelancing, and remote collaboration.
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Helped grow the local engineering network tenfold through mentorship and advocacy.
-
Lead Mobile Engineer (Consultant)
INGSOFTWARE - 10 months
A technology company developing connected fitness applications integrating BLE sensors and wearables.
-
Led iOS application architecture redesign using MVVM and RxSwift to improve code maintainability.
-
Improved Bluetooth communication reliability from 70% to nearly 100% through optimized multithreading.
-
Built abstract communication layers for BLE devices, supporting multiple sensor types and vendors.
-
Created a local iOS server with Swifter to mock APIs, enabling offline development.
-
Delivered a proof-of-concept Android version using Kotlin for cross-platform testing.
Technologies:
- Technologies:
Swift
Kotlin
MVVM
Realm
Alamofire
BLE
-
Lead Android Engineer
Johnson & Johnson Health and Wellness Solutions - 1 year 3 months
J&J’s Health and Wellness division develops digital solutions supporting healthy lifestyles, preventive care, and chronic disease management.
-
Led development of multiple HIPAA-compliant mobile applications used by thousands of patients.
-
Designed modular Android architecture to support dynamic content updates and multi-device sync.
-
Integrated apps with Salesforce backends using complex synchronization algorithms.
-
Mentored 5+ developers, conducted weekly code reviews, and optimized CI/CD pipelines for consistency.
-
Ensured code quality, performance, and scalability through strict review and test standards.
Technologies:
- Technologies:
Java
Jenkins
Kotlin
Retrofit
MVVM
Jira
- Dagger
Salesforce
-
Android Team Lead (Consultant)
Infinite Leap - 11 months
Infinite Leap provides location and asset management solutions for healthcare and logistics enterprises.
-
Managed Android team delivery cycles and introduced structured sprint planning and retrospectives.
-
Defined and enforced coding standards, improving overall codebase consistency and quality.
-
Implemented code review and testing workflows, reducing bugs pre-release.
-
Collaborated with PMs and designers to align mobile roadmap with client requirements.
Technologies:
- Technologies:
Java
Retrofit
Jira
Git
- Dagger
-
Lead Android Engineer
Circle Medical - 5 years
Core member of the mobile team responsible for building Circle Medical’s Android platform from the ground up and scaling it to tens of thousands of active users.
-
Developed HIPAA-compliant Android applications using Java and Kotlin, transitioning the app architecture from MVP to MVVM.
-
Implemented mission-critical features such as video consultations, chat messaging, payment processing, insurance scanning, and PDF viewing.
-
Integrated SDKs like ZoomUS, Stripe, Acuant, and PubNub for communication, payments, and real-time data streaming.
-
Designed modular architecture, enabling parallel feature development across teams and improved scalability.
-
Set up automated test suites using Espresso, JUnit, and Mockito, increasing stability and reducing crash rates by 40%.
-
Collaborated with backend teams to ensure data synchronization and compliance with healthcare standards.
Technologies:
- Technologies:
Java
Android
Kotlin
Firebase
Retrofit
Mockito
Espresso
MVVM
JUnit
Agile
- Dagger
- Team Leading
Gradle
Stripe
Android Jetpack
Bitrise
-
Senior Mobile Engineer
Toptal - 10 years 10 months
Client Engagements:
-
Led dozen mobile projects for clients ranging from startups to global enterprises, including Nike, Coca-Cola, and Johnson & Johnson
-
Served as Lead Mobile Engineer for a Y Combinator–funded startup, delivering a highly optimized mobile application
-
Achieved 99.5% app stability, reduced crash rates by 40%, and supported a 20% increase in user base within 6 months
Leadership & Mentoring:
-
Led 3 major delivery projects, including projects within Johnson & Johnson, ensuring 100% on-time delivery through improved processes and clear technical direction
-
Mentored 5+ junior developers through weekly code reviews and pair programming, contributing to 30% reduction in development time as well as improved code quality and increased team productivity and client satisfaction.
Technologies:
- Technologies:
Java
Android
iOS
Swift
Kotlin
Retrofit
- Dagger
Realm
RxSwift
-
CEO & Android Team Lead
Singularity Software - 1 year 3 months
Founded a software agency specializing in Android development, delivering products for startups and enterprise clients worldwide.
-
Managed a 13-member development team delivering 15+ Android applications.
-
Architected an enterprise-grade app for the oil industry with dynamic UI generation from REST APIs.
-
Rebuilt and modernized “My Diet Coach,” integrating Material Design and CI/CD — scaling the app to over 10M users.
-
Promoted clean architecture, automation testing, and open-source adoption across the team.
Technologies:
- Technologies:
AWS
Java
Retrofit
Travis CI
Bluetooth
- NFC
-
Senior Android Engineer
Scopic Software - 7 months
Scopic Software builds custom software solutions for global clients in healthcare, education, and entertainment.
-
Developed six Android apps integrating Google APIs and third-party REST services.
-
Implemented a Java-based heart rate detection algorithm using fingertip image analysis.
-
Established internal code standards and reusable libraries to improve efficiency.
Technologies:
- Technologies:
Java
Android
Retrofit
Espresso
-
Mobile Engineer
Various Clients - 14 years 9 months
Aleksandar developed mobile and fullstack solutions for clients in finance, FMCG, eCommerce, and logistics.
- Built Android and Flutter applications for startups with rapid MVP cycles.
- Delivered multi-language, offline-capable mobile apps using Room, Retrofit, and WorkManager.
- Integrated Firebase services for analytics, remote configuration, and crash reporting.
- Refactored legacy Java apps to Kotlin, reducing code size and improving maintainability.
- Built multiple Android and web projects for small businesses and non-profits.
- Integrated APIs such as JustGiving, Twitter, Google Maps, and PayPal using OAuth.
- Delivered dynamic websites with JavaScript and jQuery for interactive frontends.
Technologies:
- Technologies:
PHP
HTML
CSS
jQuery
Flutter
Java
Android
Swift
Kotlin
Firebase
Retrofit
MVVM
OAuth2
- Dagger
Realm
Material-UI
REST API
Android & Web Developer (Freelance)
Various Clients - 2 years
-
Built multiple Android and web projects for small businesses and non-profits.
-
Integrated APIs such as JustGiving, Twitter, Google Maps, and PayPal using OAuth.
-
Delivered dynamic websites with JavaScript and jQuery for interactive frontends.
Technologies:
- Technologies:
PHP
JavaScript
HTML
CSS
jQuery
Java
OAuth2
REST API
-
Software Developer
Microsoft Development Center Serbia (MDCS) - 2 years
Microsoft Development Center Serbia is one of Microsoft’s global R&D hubs, focusing on software innovation and distributed systems.
-
Developed internal tools and test automation systems for Windows and Office teams.
-
Contributed to UI automation frameworks for validation of Windows mobile components.
-
Assisted in backend service design for telemetry data ingestion.
-
Participated in agile sprints, bug triaging, and code quality reviews.
-
Collaborated with cross-functional global teams to align software integration processes.
Technologies:
- Technologies:
MSSQL
C#
.NET
DevOps
WPF
Agile
-
Education
MSc.Computer Science and Software Engineering
University of Nis, Serbia · 2011 - 2014
BSc.Computer Engineering
University of Nis, Serbia · 2007 - 2011
Portfolio
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