Denis Andros, Developer in Kraków, Poland
Denis is available for hire
Hire Denis

Denis Andros

Verified Expert  in Engineering

Mobile Developer

Kraków, Poland

Toptal member since November 8, 2021

Bio

Denis is a software developer with 12+ years of experience in Android and iOS mobile native development and architecture. He is an expert in Kotlin, Java, Swift, Objective-C, .NET, and C++. With solid technical and communication skills, Denis easily solves technical leadership challenges and provides guidance to development teams.

Portfolio

TrustArc Inc
Kotlin, Java, Swift, iOS, Android, Android SDK, SDKs, Flutter, Dart, Plugins
ShiftKey, LLC
Android, Kotlin, Android SDK, Android Jetpack, Android Studio, Coroutines...
Rider
Android, Android Studio, Kotlin, KOIN, Firebase, iOS, Xcode, CocoaPods...

Experience

  • Android - 10 years
  • Mobile Development - 8 years
  • iOS - 8 years
  • Objective-C - 8 years
  • Kotlin - 8 years
  • Java - 8 years
  • Swift - 6 years
  • Salesforce - 4 years

Availability

Part-time

Preferred Environment

Android, iOS, Salesforce, Mobile Development

The most amazing...

...things I've delivered and maintained as a team member are mobile and enterprise app products with over one million users.

Work Experience

Android and iOS Developer

2023 - 2024
TrustArc Inc
  • Integrated the IAB’s Transparency and Consent Framework (TCF) v2.2 into mobile consent management SDK for Android and iOS.
  • Integrated the Google consent mode into mobile consent management SDK for Android and iOS.
  • Implemented a Flutter plugin (supports iOS and Android) for consent management SDK.
Technologies: Kotlin, Java, Swift, iOS, Android, Android SDK, SDKs, Flutter, Dart, Plugins

Senior Android Engineer

2021 - 2023
ShiftKey, LLC
  • Advanced a healthcare scheduling app, creating an easy-to-maintain and scalable tool for healthcare workers.
  • Delivered the major features of the application with Kotlin and Jetpack Compose.
  • Developed custom Jetpack Compose user interface components.
  • Implemented a pixel-perfect UI using Figma, Android Jetpack Compose, and other native Jetpack components.
Technologies: Android, Kotlin, Android SDK, Android Jetpack, Android Studio, Coroutines, Jetpack Compose

Senior Android iOS Developer

2019 - 2022
Rider
  • Built an Android application that unifies a network of stores of goods for extreme sports such as snowboarding, skiing, cross-country skiing, etc. The app is available here: play.google.com/store/apps/details?id=com.rider.promo.
  • Developed the iOS version of the same application for the App Store (https://apps.apple.com/by/app/%D1%80%D0%B0%D0%B9%D0%B4%D0%B5%D1%80/id1321797151).
  • Architected eCommerce applications that manage discounts, promos, and news.
Technologies: Android, Android Studio, Kotlin, KOIN, Firebase, iOS, Xcode, CocoaPods, Firebase Cloud Messaging (FCM), Firebase Cloud Functions, Firebase Authentication, Firebase Analytics, Firebase Realtime Database

Android Tech Lead | Developer

2021 - 2021
NDA
  • Developed the patient services mobile app for a pharmaceutical company, including medication tracking and reminders, disease activity trends, charts and reports, patient adherence tracking, and education content media library.
  • Built the system architecture, created solution designs, performed team technical leadership, and developed the application.
  • Supported offline content management, integrated with the Salesforce SDKs—SmartSync and SmartStore.
Technologies: Android, Kotlin, KOIN, Salesforce

iOS Tech Lead | Developer

2019 - 2021
Imperial Tobacco
  • Developed the enterprise app suite for iPad to help sales representatives with the in-field sales solutions integrated with Salesforce: product orders, route planning, warehouse and stock management, and customer and outlet management or assessment.
  • Led a technical team and developed the application, system architecture, and solution designs.
  • Integrated with the Salesforce SDKs, specifically with SmartSync and SmartStore, and maintained offline content management.
Technologies: iOS, Swift, Objective-C, Salesforce, Core Data, AVKit

iOS and Android Technical Lead | Architect

2018 - 2019
NDA
  • Developed an enterprise passwordless authentication solution for iOS and Android that allows individuals to authenticate into workstations—macOS, Win, Linux—and other sensing assets simply by being close to it.
  • Created the secured Bluetooth communication, emulated PIV card, and optimized the device battery usage.
  • Created the system architecture and solution designs, managed a team of technical experts, and oversaw the application development.
Technologies: Android, iOS, Kotlin, Swift, Bluetooth Low Energy (LE)

iOS and Android Technical Lead | Developer

2015 - 2018
Anytime Fitness
  • Developed the Anytime Fitness and personal trainer applications for Android and iOS.
  • Migrated the codebase from Objective-C and Java to Swift and Kotlin.
  • Implemented various features such as training workouts, chat, and calendars.
  • Developed the solution designs, acted as the technical team leader, and managed the application development.
Technologies: iOS, Android, Swift, Kotlin, Objective-C, Java, .NET, Firebase

Mobile Developer

2012 - 2015
Coherent Solutions
  • Developed healthcare plans and Benefits of WEX for Android/iOS applications.
  • Proposed, designed, and developed applications architecture.
  • Developed major application features such as biometric login/barcode scanner.
  • Developed and instrumented CI with integration tests.
  • Worked on various tasks, as needed, including caching, fixing bugs, making improvements (UI, memory, code), sending tracking data, and writing tests.
Technologies: Android, Java, iOS, Objective-C

C/C++ .NET Developer

2009 - 2012
Coherent Solutions
  • Developed a .NET-based framework developed to substitute legacy DCOM-based transport used in the data engine. Xenon Computing Platform (TMxe) provides a TCP message transport between applications and servers.
  • Created server and client-side proxy components and allowed the client application to operate with the data in the relational database as a set of COM objects within the given object model. Data Engine is a COM-based data management platform.
  • Performed Oracle and MS SQL Server support for Data Engine via OLE DB.
  • Designed and implemented thread pool-based message processing under system heavy load.
  • Improved platform performance and stability, like memory consumption and deadlocks.
Technologies: C++, C#, C#.NET, .NET, Transmission Control Protocol (TCP), TCP/IP, Networking, Oracle, Microsoft SQL Server, OLE DB

C/C++/.NET Developer

2006 - 2012
Coherent Solutions
  • Worked on employee time management systems that reduce labor costs through automated scheduling, recording, reporting, and controlling work schedules.
  • Designed and developed GUI and ActiveX components.
  • Performed Oracle/MS SQL support for data engine via OLE DB.
  • Created the universal COM object accessor as interop for JavaScript engine.
  • Developed the ESR platform, a web-based HR enterprise system.
Technologies: C++, Microsoft Foundation Class (MFC) Library, Microsoft Foundation Classes (MFC), ATL, COM, Win32 API, ActiveX, .NET, C#, C#.NET, ASP.NET MVC, JavaScript, HTML, CSS, OLE DB

C/C++ Developer

2004 - 2006
Coherent Solutions
  • Worked for John Deere: Field Doc, an American manufacturer of agricultural, construction, and forestry machinery.
  • Developed applications executed under the VxWorks operating system. The applications help to manage the controllers installed on agricultural vehicles.
  • Designed and implemented the GPS decode module component.
  • Implemented the flag module component. Identified and fixed existing system bugs.
Technologies: C, C++, VxWorks, Microsoft Foundation Class (MFC) Library, Microsoft Foundation Classes (MFC), Win32 API, CAN Bus, RS-232, GPS, A-GPS

ShiftKey Android / iOS Applications

https://www.shiftkey.com/
ShiftKey platform helps nursing, therapy, and dental professionals to find & work shifts. I was involved in mobile app architecture & major features development.

https://play.google.com/store/apps/dev?id=8426692984949227741&hl=en_US&gl=US
https://apps.apple.com/us/app/shiftkey-prn-healthcare-jobs/id1532097671

• Advanced a healthcare scheduling app, creating an easy-to-maintain and scalable tool for healthcare workers.
• Delivered the major features of the application with Kotlin and Jetpack Compose.
• Developed custom Jetpack Compose user interface components.
Implemented a pixel-perfect UI using Figma, Android Jetpack Compose, and other native Jetpack components.
• Integrated Lottie animations
• Implemented Geofecing / Digital Invoicing app features

Anytime Fitness, Anytime Workouts (Android / iOS Applications)

https://www.anytimefitness.com/
https://play.google.com/store/apps/details?id=com.anytimefitness.app&hl=en_US
https://apps.apple.com/us/app/anytime-fitness/id914150199
https://apps.apple.com/us/app/anytime-workouts/id1112706781

Developed the Anytime Fitness and Personal Trainer applications for Android and iOS.
• Successfully migrated the existing codebase from Objective-C and Java to Swift and Kotlin, enhancing overall performance and maintainability.
• Pioneered the implementation of a multitude of features, including training workout functionality, real-time chat functionality, and integrated calendar capabilities.
• Drove the solution design process, assuming the role of technical team leader and effectively coordinating the application development efforts.

Features implemented:
• Access to over 1,000 workouts.
• Communication with a coach or personal trainer; tracking progress.
• Finding gym locations and contact information.
• Club offers and promotions.
• Scheduling, viewing, confirming, and canceling appointments.

Mobile Software Development

Created apps to maintain employee benefits. The client platform provides a variety of reimbursement and savings account offerings to help easily support employees' health and wellness while helping them save money.
1997 - 2002

Bachelor's Degree in Artificial Intelligence

Belarusian State University of Informatics and Radioelectronics - Minsk, Belarus

Libraries/APIs

REST APIs, Microsoft Foundation Class (MFC) Library, Win32 API, ATL, AVKit, Microsoft Foundation Classes (MFC), CocoaPods

Tools

Android Studio, Xcode, AppCode, Git, Android Jetpack, DJI SDK, Firebase Cloud Messaging (FCM), Firebase Authentication, Firebase Analytics

Languages

Kotlin, Swift, Java, Objective-C, JavaScript, C++, C, C#, C#.NET, HTML, CSS, GraphQL, Dart

Frameworks

Android SDK, .NET, Core Data, KOIN, ActiveX, ASP.NET MVC, Flutter

Paradigms

Mobile Development

Platforms

Android, iOS, Salesforce, Bluetooth Low Energy (LE), Firebase, VxWorks, Oracle

Storage

Microsoft SQL Server, Firebase Realtime Database

Other

Coroutines, Jetpack Compose, Mobile Apps, SDKs, Mapbox SDK, Software Development, Systems Engineering, Lottie, Geofencing, CAN Bus, RS-232, COM, OLE DB, Transmission Control Protocol (TCP), TCP/IP, Networking, GPS, A-GPS, Firebase Cloud Functions, Plugins

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