Aleksandar Ilic, Developer in Belgrade, Serbia
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Aleksandar Ilic

Verified Expert  in Engineering

Android Developer

Belgrade, Serbia
Toptal Member Since
November 9, 2014

Aleksandar has worked on various software and product development projects for Toptal clients as an Android developer, for clients through his own agency as a developer, project manager, and business owner, and also on his own startup projects as a founder and technical co-founder. He understands software products and their lifecycle from various perspectives and roles. He is an open-minded individual with excellent strategic, analytical, and empathic skills.



Preferred Environment

Git, Android Studio, OS X

The most amazing...

...product I've built is an Android tablet software for creating standardized documentation for conservators and restaurateurs.

Work Experience

Founder and Senior Android Developer

2017 - PRESENT
Appollo Fortyone LLC
  • Worked closely with leads on closing the sales and defining the project requirements and specifications for the designers and developers.
  • Recruited designers and developers for incoming projects.
  • Led Android development and mentored junior and mid-level Android developers on several projects for startups and enterprises.
  • Worked on the development of a new product for the telco enterprise client.
  • Consulted and coached startup founders to understand what would be the MVP for their idea and how to implement it efficiently.
Technologies: Kotlin, Android

Senior Android Developer

2022 - 2023
  • Worked on the Android development of an offline first ticketing application that operates with a large amount of structured and binary data for the client from the construction industry using the latest technologies and best practices.
  • Built the analytics library for saving page impressions on screen closes.
  • Implemented a PDF reader using Android components and worked with map tiles.
Technologies: Android, Offline-first Development

Senior Android Developer

2020 - 2021
Vertt AG (via Appollo Fortyone)
  • Recruited and assembled a team of three highly skilled senior developers.
  • Led the software audit of the entire client's software architecture—Android, iOS, and Node.js back end. The audit result was a 25-pages document reviewing the entire architecture, comparing it against best practices and recommendations.
  • Led the refactor of software architecture for rider and driver Android apps.
  • Worked and mentored an in-house Android developer.
Technologies: Android, Model View ViewModel (MVVM), Kotlin

Senior Android Developer

2020 - 2020
  • Refactored the Android app for collecting patient-reported outcomes.
  • Designed and implemented a custom survey form definition language (FDL) to be used by the back end team to dynamically control the survey questions and the UI of the questions.
  • Implemented the possibility to write business logic in FDL on the back end in JavaScript, which gets executed on the Android app.
Technologies: Android, Kotlin, JSON-RPC, SQLite

Senior Android Developer

2019 - 2019
Blu World, Pte., Ltd.
  • Took over the app development from the previous vendor and assessed its current state.
  • Refactored the existing code to meet the latest development guidelines.
  • Implemented missing features to meet the client's goals and expectations.
  • Maintained the app and supported the client in its post-release phase.
  • Handed over the project to the in-house developer.
Technologies: Stripe, Kotlin, Java, Android

Senior Android Developer

2016 - 2017
Mulberrys Garment Care
  • Developed an Android app for requesting dry cleaning services.
  • Developed an accompanying Android app for drivers to receive pickup and delivery requests.
  • Maintained both Android apps and developed new features.
Technologies: Google Maps SDK, Android

Android App Developer

2015 - 2016
Divvy Ride, Inc. (via Toptal)
  • Developed an Android app for requesting immediate and scheduled rides.
  • Developed an accompanying Android app for drivers to receive ride requests from customers.
  • Built both rider and driver apps as a sole developer from start to finish.
Technologies: Google Maps SDK, Facebook API, MongoDB, Node.js, Android

Android Developer

2015 - 2015
Yaacomm (via Toptal)
  • Created a utility Android application for people working in CAO Hospitals which could be used to do some CAO related calculations, find helpful information, and explore the service agreement presented as a book with chapters and navigation.
Technologies: HTML, JSON, Android


2015 - 2015
Centaurtek (via Toptal)
  • Created SafeDrive, an Android app for recognizing car drives and driving events during a drive (such as acceleration, break, turns, etc.) from multiple data sources such as Google's Activity Recognition API, GPS locations, accelerometer, and gravity sensors. Parse was used to store the data and app supported full offline mode.
Technologies: Parse, Accelerometers, GPS, Android

Android Engineer Consultant

2012 - 2014
Sony Mobile (via PSTech)
  • Created a system framework for storing information about sent and received files over a call.
  • Brought in AOSP's source code for a contact editor into the existing phonebook application.
  • Improved a smart search algorithm to better match who to call next.
  • Improved existing Phonebook source code to be compatible with the latest Android API level.
  • Refactored a phonebook application to use AOSP's BiDi framework instead of the deprecated OEM's BiDi framework.
Technologies: Bash, SQLite, Android, Java

Android Engineer

2012 - 2014
  • Worked as an off-site and on-site consultant for Sony Mobile on Phonbook project. Engagement details are provided as a separate employment.
  • Created a modular architecture for a mobile device management Android software.
  • Introduced Gitflow workflow in a five-person team.
Technologies: SQLite, Android, Java

Android Software Developer Intern

2011 - 2012
Vip Mobile
  • Created an application for checking account balance by mobile subscription, buying tariff add-ons, and finding all related information regarding the Vip mobile operator.
  • Implemented a function to find the nearest Vip store from the app.
  • Collaborated with a UI designer to create the user experience design and app flow.
Technologies: Android, Java

Mobile Software Developer

2010 - 2011
Wireless Media
  • Created an Android tablet application for taking customized surveys from retail sellers directly on the field according to the schedule. The application required authentication and used a REST back-end to fetch data about the retail stores' schedules and survey templates. The application had to support an offline mode and restrictive data uploads such us uploding photos only over wifi.
  • Created an Android app store for a Serbian TelCo operator which offered recommendations for Android apps and opportunities to download exclusive apps.
Technologies: Bada, C++, Android, Java

Finlab Finances
Finlab is an Android app for recording financial expenses. I implemented the back end in Ktor (Kotlin) with a PostgreSQL database which had to connect to multiple APIs to acquire all the necessary data for the receipts. I also implemented the Android app with custom QR Code scanner implementation using native ZBar and OpenCV libraries.

Viber GPT Chatbot

A Viber chatbot using the OpenAI GPT-3.0 and GPT-3.5 API to respond to chat messages. The back end was written in Ktor with PostgreSQL as the database. It was connected with the OpenAI API to generate message completions that were then replied to by users. The back-end architecture was built to support multiple chat vendors (such as WhatsApp, Slack, etc.).


I led the refactoring of the entire software architecture for both passenger and driver Android apps. I fixed major production bugs and designed better solutions for existing features. I also mentored the Android developers on best practices and libraries as part of my role in this project.

Universal Telecom Mina Sidor
An Android app for Universal (Swedish telco operator) customers. Users can log in through BankID, keep track of used mobile data, and buy more if needed. The app provides a good overview of services, extra services, usage, invoices, time of the agreement, and more, as well as customer service and live chat, available every day of the week. Notifications are sent during operational disturbances, and an inbox organizes all communication regarding services with Universal in one place.

Eurovelo 6: The Danube Route
An Android app for all cyclists that plan to spend a few days on the wheel riding long distances along the Danube. Based on the data European Cyclist Federation collected during EuroVelo 6 route assessment, this app provides dozens of useful pieces of information.

Hazelnut Game
An Android app for challenging your friends with crazy challenges.

Mulberrys Cleaners
An Android app for requesting dry cleaning services.

Mulberrys Driver

An Android app for drivers to receive pickup and delivery requests from the dry cleaning services company.

DivvyRide Rider for Android
An Android app for requesting immediate rides and scheduling advanced rides in the future.

DivvyRide Driver for Android

An Android app for DivvyRide drivers to receive ride requests from customers.

Software for creating standardized conservation and restoration documentation build for the Institute for Protection of Cultural Monuments of Serbia. It helps conservators and restaurateurs to highlight damage and previous restorations on a photo of mosaics or frescos while on the field. Every damage or restoration is created as a separated layer which can be overlapped with other layers when creating reports for further analysis. I worked with the domain experts on product development and afterwards implemented the Android application from start to finish.


An Android application to calculate how much in taxes and excises are you paying on every purchase. It was built for a non-governmental organization as part of a project for raising awareness about government spending. Registration was required using Facebook or Twitter.

Osmatrac Apps
Osmatrac is a collection of public MJPEG cameras with streaming capability in one application. Most of the available cameras are publicly available traffic cameras which led to the huge popularity of Osmatrac amongst drivers in Belgrade, Serbia. Originally built for Android and afterwards for Samsung Smart TV. I have developed apps for both platforms, including the back end, which was implemented in Google App Engine.


A sport portal for which I have developed an Android application that connects to a REST back end. Beside news, there are also live football scores with match details.


An Android application developed for a client with specific tracking requests. There was no UI and it was controlled by sending SMSes to a device where it was installed. The app supported several tracking modes which included features such as detecting device movements by using available sensors on the device, collecting the device's location from available sources, audio recording surroundings, and real-time uploading of all collected data to a server.

Developer’s Choice Award at Vip Android Challenge 2.0

I won a Developer's Choice award at a local Android challenge for a TV Guide application. Users could track TV program schedules in Serbia, create a list of favorites, search content by name and genre, and set reminders for their favorite shows and movies. The app wound up being preinstalled in all Android devices sold by Vip TelCo operator.

Awards "Best Bada Applications" and "The Best Student Application" at Vip Challenge 3

I have won two awards from local mobile development challenges for TV Guide applications for the Samsung Bada platform (now discontinued). The application was a ported light version of my TV Guide for Android. It was developed in C++ and Bada IDE and supported only the basic functionality of the original Android version.

Bring Up Process Talk at Mobile Monday

Together with my colleague, we described the process for Android OS development and explained in detail the phases of the Bring Up process by providing examples from the development of Phonebook and E-mail Sony Mobile applications at a Mobile Monday event.

Lecture on Android Development

I gave a lecture designed for engineers interested in Android development. The contents of the lecture included Android’s basic components and best practices with emphasis on the communication between those components.
2008 - 2012

Bachelor's Degree in Computer Science

School of Computing (RAF), Union University - Belgrade, Serbia


Startup Launch Academy



NLP Practicioner

International Association of NLP Institutes (IN)


Wingwave Coach



Android Support Library, Google Maps, Firebase Android SDK, REST APIs, Accelerometers, Node.js, Google Maps SDK, Stripe, Facebook API, JSON-RPC, Socket.IO, OpenCV, Viber API


Git, Android Studio, Firebase Analytics, Android Jetpack, Gerrit, Jenkins, ZBar


Android SDK, Rx, Ktor


Android, Firebase, OS X, Parse, Google App Engine, Linux


Kotlin, Java, SQL, HTML, Bash, Swift, C++, C, JavaScript, Python 3, Python


REST, Agile Software Development, Object-oriented Design (OOD), Design Patterns, Scrum, Clean Code, Continuous Integration (CI), Test-driven Development (TDD), Unit Testing, Model View ViewModel (MVVM), Design Thinking, Offline-first Development


JSON, MongoDB, SQLite, PostgreSQL, DB


Google Material Design, User Interface (UI), AOSP, Lean Development, Product Development, Startup Consulting, Bada, GPS, Custom Views, Lean Startups, New Product Development, Minimum Viable Product (MVP), Entrepreneurship, Ideation, Critical Thinking, Coaching, Coroutines, Algorithms, QR Codes, OpenAI GPT-3 API, Viber Bots

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