Nikola Vasović, Developer in Belgrade, Serbia
Nikola is available for hire
Hire Nikola

Nikola Vasović

Verified Expert  in Engineering

Full-stack Developer

Location
Belgrade, Serbia
Toptal Member Since
October 4, 2019

As a software engineering master's graduate and the holder of a prestigious national scholarship, Nikola kickstarted his full-stack developer career at Toptal. Leveraging expertise in Flutter for cross-platform mobile development, he specialized in streamlining MVP product launches for startups. Nikola co-founded and acted as the CTO of Varius Development and extended his DevOps and PM expertise while collaborating with prominent global enterprises, transforming into a versatile IT professional.

Portfolio

Varius Development
Bootstrap, CSS, HTML, JavaScript, MySQL, CodeIgniter, PHP, Docker, Laravel...
LibraHealth Inc.
Flutter, Firebase, Cloud Firestore, ChatGPT, Dart

Experience

Availability

Part-time

Preferred Environment

Flutter, Firebase, Cloud Firestore, Dart

The most amazing...

...project I implemented was the Cardiac Health Canada Flutter app. It secured a multi-million dollar investment after the MVP launch, reshaping digital health.

Work Experience

Chief Technology Officer

2020 - PRESENT
Varius Development
  • Led a team of 25 software engineers that provided remote outsourcing services as a startup for Samsung Electronics, Authority Builders Co., Ahold Delhaize, Pfizer, Fresh Step, Avangard Innovative, Tourist Mobile, etc.
  • Played a significant role in performing technical interviews and assembling a team of the most talented software engineers from the University of Belgrade, capable of collaborating in the office and delivering high-quality code for such a big client.
  • Developed core system features, prepared code structures, and designed employee architectural patterns. Introduced each employee to the project and found best-fit positions and teams to maximize utilization.
  • Supervised implementation processes that employees took part in by reviewing their code, reports, and issues for tasks I previously assigned them with Jira and Trello. Managed sprints and made full planning of the development process.
  • Oversaw and collaborated on integrating, developing, and securing different 3rd-party software services for payment processing, authentication, and marketing, directly affecting the clients' incomes.
  • Managed a team as a technical project manager and lead developer that delivered multiple web development software solutions for Samsung Adriatic, Samsung UK, and Samsung IE by creating them from scratch and enhancing the existing ones.
  • Implemented web application features for massive sale campaigns and promotions (e.g., Black Friday) with the team, which successfully helped the clients gain thousands of customers.
  • Involved in deploying the client's web platform programming code by using automatically configured Git hooks to multiple environments. Set up automatic deployment using Docker and GitLab software.
  • Provided front-end, back-end, and full-stack development, mainly in Flutter (Android and iOS applications), PHP, and Laravel, on core features on most of the projects we outsourced.
Technologies: Bootstrap, CSS, HTML, JavaScript, MySQL, CodeIgniter, PHP, Docker, Laravel, Java, Node.js, React, MongoDB, Angular, Azure, Kubernetes, React Native, Flutter, Dart, Firebase, Cloud Firestore, PostgreSQL, Linux, Google Cloud, Amazon Web Services (AWS), Spring Boot

Flutter Developer

2023 - 2023
LibraHealth Inc.
  • Engineered multiple mobile applications catering to medical needs, predominantly serving the Canadian region. These apps have led to advancements in medical services and digital solutions.
  • Partnered with a medical doctor who doubles as a back-end developer, leading us to discover an innovative pathway for bringing a medical solution to market.
  • Fused mobile development with OpenAI to create UnfoldMD (OpenMD) iOS and Android medical assistant applications. Merged medical knowledge with AI to support professionals and patients.
  • Developed a specialized mobile app for monitoring patients' metabolic health, tailored exclusively for QuatuorMD, a prominent Canadian clinic.
  • Contributed to strategic planning for new feature development and actively conducted system security testing throughout the testing phase.
  • Deployed production versions of App Store and Play Store applications, now actively utilized by real patients and medical professionals for practical healthcare needs.
  • Crafted an advanced algorithm leveraging Firestore's offline capabilities to optimize cloud integration, resulting in substantial cost reduction and improved operational efficiency.
  • Explored OpenAI's GPT models, like GPT-3.5, renowned for their language prowess, and integrated them with vectorial databases to elevate real-time bot chat interactions with dynamic and contextually tailored responses.
  • Explored the advanced functionalities of Flutter's GoRouter plugin to enable secure web routing, dynamic links integration, and easier handling of native and FCM push notifications.
Technologies: Flutter, Firebase, Cloud Firestore, ChatGPT, Dart

Flutter Developer

2022 - 2023
Innov8 LLC (via Toptal)
  • Developed iScreen app for iOS using Flutter, enabling parents to identify early signs of autism in children with an intuitive interface and reliable assessment tools.
  • Coded smooth UI/UX based on Figma screen designs and implemented front-end logic for communication with Kinvey services on the back end, which were maintained by Innov8 CTO.
  • Supervised the testing phase involving enrolled patients and medical professionals, addressing bugs and refining the application based on their valuable feedback.
  • Integrated a video upload and sharing feature, enabling direct peer-to-peer communication between medical professionals and assigned patients.
  • Played a pivotal role in research, task definition, and establishing overarching goals, contributing significantly to the project's stability and overall success.
  • Efficiently achieved the MVP milestone, incorporating supplementary features that enhance flexibility in interactions among diverse roles within the system, advancing the project's progress.
Technologies: Flutter, Dart

Flutter Developer

2021 - 2022
Cardiac Health Canada
  • Developed a cardiac health mobile iOS application intended to help people with heart disease in US and Canada, using Flutter as a cross-platform development tool.
  • Helped the team get a multi-million dollar investment for post-MVP stage development.
  • Used Get as a state management plugin for the app, which is back endless, having only Cloud Firestore as a NoSQL database with exclusive content. Firebase is also used for authentication purposes.
  • Built everything from scratch based on predefined design and features available in the Figma prototype. The actual app I've built looks and behaves the same as a prototype, which was the main goal for MVP.
  • Integrated Apple Health App data, which can be synchronized through a smartwatch or iPhone. This application takes and renders data from it in real time, which is very important for users to track their health.
  • Configured "Apple Store – in-app purchase" for purchasing auto-renewable yearly subscriptions to access the app. Created offer codes for promotions that the partners and testers use.
  • Integrated RevenueCat as a back-end system for making and validating purchases. RevenueCat was integrated with their native Flutter plugin since it doesn't have its 1st-party back end.
  • Rendered historical data, current progress, and community score distribution using different forms of charts (bars, lines, and more).
Technologies: Flutter, Firebase, In-app Purchases, Dart, Cross-platform App Development, iOS, Front-end Development, Cloud Firestore

Full-stack Developer

2020 - 2021
WBAM Digital (via Toptal)
  • Developed custom features for the existing SuiteCRM system (built in PHP), adapted to the requirements of Payment 1 loan company (Payment1.com). I was responsible for front- and back-end development and DevOps.
  • Created and designed MySQL database architecture, capable of supporting many records without affecting overall system performance.
  • Set up automatic daily synchronization of the CRM system to users, payments, and loan records from the data warehouse of the loan company through an SFTP connection.
  • Implemented a lot of raw database queries, supported by various indexes, to extract complete statistics of business processes in an arbitrary timeframe.
  • Introduced a tracking cookie to correctly identify unique users and referral data and make it available to the CRM. Tracking includes referrer websites, visited pages, average time spent, and more.
  • Worked on the implementation of a conversion identification system. Hence, the system connected users and their data with customers signing up in the Payment 1 loan company system.
  • Scheduled automatic email campaigns processed by Payment 1's custom email server, which were used for customer notifications, promotions, and more.
  • Migrated the whole CRM system (code and database) from Ubuntu VPS to Windows server, adapted automatic scripts and cron jobs to work in Windows environment through virtual machines.
  • Maintained web, database, and email server. Was responsible for deployment and monitoring server activities.
Technologies: PHP, SuiteCRM, JavaScript, MySQL, HTML, CSS, Ubuntu, Apache

Flutter Developer

2020 - 2020
Eunotics, Inc. (via Toptal)
  • Developed a Flutter social app called Munch, which uses a gesture-driven user interface that allows groups to decide where to eat.
  • Used Firebase to support social authentication (Google, Facebook, Apple) and user management.
  • Implemented screens' design and functionalities to look and behave exactly as in the pre-defined Invision prototype provided by the designer.
  • Introduced a location feature to the app, which allows groups to have a unique experience based on the selected location and radius distance on an interactive map with in-built Google Places API search options.
  • Implemented a lot of animations on different screens, which makes the gesture-driven interface more powerful and user-friendly, causing the product to look more professional.
  • Architected and developed a native deep-linking feature for Android and iOS, allowing new users to join the eating decision process easily. Also, a smart push notification system keeps the app's synchronization in real time.
  • Deployed the app's beta version on Android and iOS to Google Play Store and App Store.
Technologies: Front-end, Cross-platform App Development, iOS, Android, Xcode, Firebase, Dart, Flutter

Full-stack Developer (Flutter and Laravel)

2020 - 2020
Praktice LLC (via Toptal)
  • Developed an app for online personal training, where subscribed clients can see video workouts and exercises of their favorite trainers. Responsible for Flutter application, Laravel API, and Laravel MVC Admin Panel.
  • Refactored the code structure on both sides (Flutter and Laravel API) to be reusable and adjusted with all recommended design patterns (Flutter BLOC, REST API).
  • Fixed all design issues in Flutter, created new screens and functionalities based on design provided in Adobe XD file. The design of all pages is adjusted to different screen sizes and device pixel ratios.
  • Reimplemented API logic in Laravel, including the social login, subscriptions, search, feed, favorites, and profile.
  • Added new functionalities to the existing admin panel, including image and video upload and standard forms using Laravel MVC pattern. The front end was implemented using HTML, CSS, Bootstrap, JavaScript, and jQuery.
  • Localized all parts of the system (Arabic and English). Flutter app localized with language JSON sheets, Laravel API returned localized database columns based on HTTP Accept-Language header.
  • Deployed Android and iOS Applications to Google Play Store and App Store (Test Flight).
Technologies: Ajax, Xcode, Android, Dart, REST API Architecture, Back-end, Full-stack, Trello, CSS, HTML, jQuery, Bootstrap, JavaScript, MySQL, PHP, Laravel, Flutter

Full-stack Developer

2019 - 2020
Kintek Group (via Toptal)
  • Developed the "COVID Access" mobile app using the Flutter framework and Spring Boot and PostgreSQL. It provides COVID-19 Stats for the US, locations of test centers, test results, business events, and other stuff to help fight this disease.
  • Deployed Android and iOS "COVID Access" applications to Google Play Store and App Store (Test Flight).
  • Developed multiple web portals from scratch, used by 100+ airline companies (American Airlines, Delta Airlines, and Air Canada). These portals provide bulk import of data, generation of different reports (PDF, Excel), and extensive data management.
  • Worked on code and functionality enhancements of existing web portals used by the biggest airline companies, where they can track employees, tasks, projects, aircraft, and engines. The tech stack included PHP, MySQL, HTML, CSS, and JavaScript.
  • Integrated the Okta multi-factor authentication system into all existing and newly created web portals as a mandatory security feature for all users.
  • Remediated code and database structure of all existing web portals to overcome all security holes reported by automatic testing tools (code scanning reports, web application security tests, and more).
Technologies: Ajax, Firebase, Xcode, Android, Hibernate, Web Development, jQuery, Java, Back-end, Full-stack, Bootstrap, JavaScript, CSS, HTML, PostgreSQL, MySQL, Spring Boot, Dart, Flutter, PHP

Web and Mobile Developer

2017 - 2020
Freelance
  • Developed a cross-platform (iOS, Android) social network app in Flutter, Spring Boot REST API, and Laravel admin panel. This was used by the Makeover Academy and its students.
  • Implemented a generic CMS for eCommerce websites, which is now successfully used by several companies in Serbia.
  • Created and tested a secure REST API for webshop sales statistics and reports, invoices, authentication, and more.
  • Built multiple webshops using MVC architecture, with the integration of the aforementioned generic CMS and REST API.
  • Developed the complete front and back end of a website that hosts recorded classes for many courses at the University of Belgrade, School of Electrical Engineering, which is extremely helpful to students preparing for and passing exams.
  • Built the back end of a web application that connects teachers with students and supports the booking process for private lessons, authentication, and payment.
Technologies: Ajax, Firebase, Xcode, Android, Flutter, Web Development, REST API Architecture, Bootstrap, Back-end, Full-stack, jQuery, JavaScript, CSS, HTML, PostgreSQL, MySQL, Hibernate, Spring Boot, Dart, Java, PHP, Laravel

iScreen (iOS and Android)

https://innov8.care
I significantly contributed to developing Innov8's iScreen app, a medical tool for early autism detection built with Flutter. My role focused on ensuring a seamless user experience, robust back-end connectivity, and enabling direct interaction between medical experts and parents. Notably, the app rapidly generated digitally signed diagnostic PDFs, streamlining the diagnostic process and reflecting Innov8's commitment to transforming autism care.

I translated design ideas into an intuitive interface and collaborated closely with Innov8's CTO to establish reliable front-end-back-end communication.

KEY FEATURES
• Streamlined user registration for providers and patients
• Secure credential verification for providers' licenses and diplomas
• Simplified child registration for parents with accessible documents and media uploads
• Efficient provider-patient matching for optimal healthcare connections.
• Enabled digital diagnosis creation with signed PDFs, advice, and prescriptions
• Integrated push notifications for timely updates on diagnosis completion

The app was successfully released to App Store as MVP and was tested and refined based on feedback from medical experts and patients.

QuatuorMD (iOS, Android and Web)

https://quatuormd.ca/en/
QuatuorMD is an application available across the web, iOS, and Android platforms, exclusively designed for clients of the QuatuorMD clinics in Canada. The app empowers patients to monitor their metabolic health and provides convenient access to content and information about the Quatuor clinics. With user access managed through the clinic's CRM, the app ensures a secure and personalized experience, eliminating the need for 3rd-party authentication services.

As a Flutter developer, I focused on turning Figma's design ideas into mobile and web apps. I also handled the behind-the-scenes work, connecting the app to Firebase Auth, Firestore, Dynamic links, and custom AWS back end. To make things run smoothly, I made Firestore work better by using offline cache and custom ways to store data, which led to significant cost reduction of cloud services.

Also, I integrated advanced features like Firebase Phone validation and MFA for admin users, enhancing security while retaining convenience. I expanded accessibility through a responsive web platform using Flutter's capabilities, serving clients and professionals. Real-time charts and score updates via listeners, sockets, and streams elevated user engagement.

UnfoldMD (iOS and Android)

UnfoldMD is an innovative AI-driven (OpenAI's GPT-4) medical chatbot designed to provide healthcare professionals with accurate and validated responses to medical inquiries and as a team member, I was crucial in developing UnfoldMD's mobile interface and front-end business logic using the Flutter framework. At the same time, my teammate ensured that the information delivered was precise and relevant using vectorial databases.

Additionally, I collaborated with the teammate to implement a feature that lists credible sources for every answer, enriching the user experience and enabling further exploration of the subject matter. Also, I created UnfoldMD's Inbox feature, which helped shape the intelligent algorithm that tailors personalized articles based on users' search queries. This feature aims to keep healthcare professionals well-informed and up-to-date within their field.

I use my Flutter proficiency to efficiently minimize cloud expenses by employing offline caching for accessing Firestore Cloud. I've established a well-structured architecture, secure rules, and integrated real-time chat listeners with standard indicators and advanced bot features.

Cardiac Health Canada (iOS)

An iOS application developed using the Flutter framework, which is designed to be used by patients who have heart diseases to help them adapt their lifestyle to feel better. The app doesn't have an associated 1st-party back end; it uses Firebase and its Cloud Firestore to store content in a NoSQL way. I worked as a solo front-end developer, defining app architecture from scratch and focusing on its robustness. Hence, its front end has a "mini back end" in separate Flutter modules.

The look and feel of the app rely on the Figma prototype. The app's core is the Get design pattern and state management system (Pub.dev, packages, and get), and it's very suitable for creating reusable and generic portions of the code, which can be implemented easily in some other application environments. The app is accessible only to subscribers registered into the RevenueCat back end using the Apple Store in-app purchase mechanism.

After subscribing, users can access health tests, daily and weekly tasks, and health data (integrated Apple Health Kit). Based on their daily activity, the app calculates scores using complex calculations to present the actual state of users' bodies.

Samsung Boost

https://samsung.com/uk/boost
Boost website is one of the samsung.com services, which is available in the United Kingdom and Ireland as two separate web applications using the common back-end. The project was designed to detect users' mobile devices - https://samsung.com/uk/boost and https://samsung.com/ie/boost pages, to serve them partner offers and promotions by generating voucher codes. Official partners generate voucher codes - Deezer, Calm, YouTube Premium, Readly, Google Play Pass, Google Play Points, Adobe Lightroom, Disney+, Fiit, and Antstream.

The app's front-end was developed using React framework, and the back-end was implemented in Node.js, while MongoDB is used on the database side. I led a team of two developers and a QA engineer as a technical project manager with some support in development and deployment.

Some of the features are:
• Samsung Account Social Sign In
• ReCaptcha Enterprise
• Device detection (eligible devices - S21 Series, Flip, Fold, Tab S7, Desktop)
• Country detection (used third-party API - https://ipdata.co/pricing.html)
• Integration of new partners (Disney+) and their voucher codes

Back-end deployment requires Kubernetes and Helm usage; Front depends on Adobe Experience Manager.

Munch (iOS and Android)

https://www.silive.com/galleries/FEVI5H4CMRF4ZP52ZGKJOEC7MU/
A social app developed by Flutter, allows groups to decide where they want to eat and it utilizes a gesture-based user interface to find nearby US restaurants and bars. The idea behind the app is to remove the back-and-forth discussions between groups by automating the decision-making process with a unique preference system.

I was responsible for implementing a complete Flutter app based on the Invision prototype that the designer provided. I collaborated with a back-end developer who prepared an API for which I integrated endpoint calls and data flow on the front end.

The app uses a location feature to select an area of interest for a group, a smart push notification system that keeps the app synchronized in real time, and deep links that allow new users to quickly join the eating decision process.

I implemented a lot of animations on different screens, which makes the gesture-driven interface more powerful. I also deployed the beta version of Android and iOS apps in the Play Store and App Store.

ECD – Crypto Exchange

https://ecd.rs/en/
A customer website and admin panel feature updates for the biggest cryptocurrency exchange in Serbia. I was responsible for the back-end development of APIs (in Laravel) used by the customer website, which was developed in parallel by another team member. Also, I had full-stack tasks on the admin panel, which has MVC architecture—the back end built in FuelPHP framework and the front in HTML, CSS, and JavaScript.

The tasks which I worked on were related to two big features:
1. Automatic handling of weekly transaction limits and user risk levels
2. Creation of secure Crypto and Fiat wallets integrated with 3rd-party systems

These features had related tasks that needed to be implemented on the admin panel and customer websites. When the 1st feature was implemented, it reduced the manual work operators previously performed. It supported uploading various personal documents used and processed by finance institutions of the countries where the site was deployed (Serbia, North Macedonia, and Australia).

Wallet development upgraded company, which only had Crypto-Fiat centralized exchange feature to the trading ecosystem with personal wallets, where customers can hold Crypto/Fiat. Implemented MFA/reCAPTCHA.

MAXI Augmented Reality (iOS and Android)

https://marvelapp.com/prototype/28ih64cg/screen/78270657
A Flutter application developed for the biggest food retail company in Serbia (MAXI—Maxi.rs), which is part of the vast global retail group—Ahold Delhaize (Aholddelhaize.com). The app aimed to perform online giveaways through puzzle games and augmented reality features. I was responsible for front-end development while another team implemented API endpoints in parallel.

The application consists of an integrated puzzle game built using the Unity framework. Besides that, there is an interactive map filled with markers on the territory of Serbia, generated by a specific algorithm that considers the user's location and the location of all retail stores in the country. Map markers represent gift boxes that can be collected using the augmented reality feature. Gift boxes are used to get giveaway products from stores and get additional lives for the game.

From the additional features, the app used Firebase Dynamic Links and push notifications. I provided weekly builds to be tested by the end company using Firebase Distribution and Test Flight.

Authority Builders

https://authority.builders
A web platform that sells guest posts on high authority websites with solid metrics and traffic stats. These websites cover various niches, including finance, education, gambling, travel, health, etc. Unlike some other link-building providers, Authority Builders provides links from trusted, real-ranking websites.

I am the head of the tech team, responsible for leading a group of six software engineers. My team works together in the office and provides remote outsourcing for Authority Builders Co. Besides managing the team, I work on core system stuff and collaborate with project managers, sales, finance teams, and founders.

The project consists of four web portals organized as separate web applications—customer, administrator, blogger, and content writer portals. Web applications based on MVC and API architecture use the CodeIgniter framework. My team is developing new features, improving existing functionalities, code optimization, front-end upgrades, and more. The most important part of the back-end stack is developing and integrating payment systems (PayPal, Stripe APIs), directly affecting Authority Builders Co's income.

CAVOK

https://cavok.oliverwyman.com/
As a full-stack developer, I took charge of vital admin platforms for top global airlines. My role involved adding new features, ensuring security based on frequent tests, and managing daily tasks.

I focused on improving the platforms by creating efficient features for tracking aircraft conditions and parts. Much of my work was maintaining tight security through regular penetration testing and implementing Okta Multi-factor Authentication (MFA) for added protection.

My routine included handling PDFs, CSVs, and generating reports essential for airline operations. I also managed internal tasks, promoting smooth communication across teams.

I utilized custom PHP and VanillaJS to build responsive web apps tailored to the airlines' unique needs. This approach helped in creating user-friendly and efficient solutions.

Praktice (iOS and Android)

https://xd.adobe.com/view/f481004a-2409-45bb-6184-a7c5c528b621-82b0/
A cross-platform app was developed using the Flutter framework for the Dart programming language. The app aimed to connect subscribed clients with their favorite personal trainers via online video workouts and exercises during the lockdown caused by the COVID-19 virus.

I was responsible for all parts of this project, including the Flutter app, Laravel API (MySQL database), and Laravel MVC admin panel. I worked as a developer who needed to fix all design and functionality issues made by developers who worked on this project from the start. I also redesigned and reimplemented all parts of this project, including refactoring code structure and creating reusable design patterns. Implemented social login, subscriptions, search, feed, favorites, and profile functionalities.

I localized both sides of the app (front-end and back-end localization) to Arabic and English. I also deployed test versions of Android and iOS apps to the Google Play Store (production) and App Store (test flights).

Samsung Competitors Platform

This web application offers users with a non-Samsung device to buy its Samsung alternative in the same class (main targets are Apple and Huawei). It was developed for the Adriatic region. Its core feature is the device brand and model recognition algorithm based on user-agent and third-party libraries. This system has an admin panel with content management features, where the admin can define products, offer contents, partners, and target groups for detection. Based on the detected target group, the relevant competitor's website is rendered, and the user can be redirected through it to the partners' shops. Partners are lead technical retailers in Serbia.

I led a team of two software engineers who delivered the product, and I was responsible for communication with the client and partners. Competitors' platform offers its API for redeeming voucher codes and tracking sales on partner's websites. Partners can sign in to their admin panel and track their vouchers.

Project is implemented in Laravel (MVC + API) with front-end stack - HTML, CSS, JavaScript, Bootstrap. MySQL is used as a database server. I set up CI/CD with Docker and self-hosted Gitlab.

COVID Access (iOS and Android)

This application, which has Flutter-based mobile application as well, communicates with 3rd-party APIs that provide COVID-19 stats for the US, locations of test centers, test results, business events, QR code ticket scanning, geolocation features, and other stuff to help fight this disease.

As a full-stack developer, I implemented it from scratch. I was also responsible for the Flutter app, which communicates with the REST API, which I implemented using Spring Boot in Java and PostgreSQL database, and 3rd-party APIs for tracking virus statistics. I was also responsible for deploying the app to Google Play Store and App Store (test flight).

Payment 1 CRM

https://payment1.com
A fork of the SuiteCRM system with many new features implemented to satisfy requirements for managing and presenting data from the warehouse of Payment 1 loan company (Payment1.com). All extensions to the existing CRM system were developed using pure PHP programming language and MySQL database (back end), and data representation was implemented using standard front-end tech stack —JavaScript, HTML, and CSS.

I was responsible for full-stack development and DevOps on the CRM side. I communicated intensively with the tech team, which maintained Payment 1 data warehouse storage and their presentation site.

ACHIEVEMENTS
• Created automatic Bash script for daily importing of users, payments, and loans from the data warehouse to the newly created CRM system (Bash script with periodical SFTP connection).
• Wrote high-quality MySQL raw queries to extract all necessary stats from the CRM to present them to the employees using it.
• Tracked user behavior with a specific algorithm, monitored their activity and average time spent and recorded sign-up conversions from various referrers.
• Set up an email server to support campaigns.

Social Network for the Makeover Academy (iOS and Android)

• Developed a cross-platform (iOS, Android) app using the Flutter framework and the Dart programming language.
• Built a back-end REST API implemented using Spring Boot in Java. The data layer is accessed via PostgreSQL.
• Implemented a Firebase API (for authentication) and Google Cloud Services (Firestore and Google Cloud Storage).
• Developed an admin platform in PHP using the Laravel framework, which connects to the same PostgreSQL database.

I was responsible for all parts of the project (excluding app design and deployment). The mobile app includes a subset of standard social network features (like a simple version of Instagram), including posts, likes, comments, followings, chats, and notifications. I also implemented additional functionalities like makeover courses and lessons (that content is uploaded through the admin panel). I used Google Cloud Storage to store social network media content (videos, images, and lessons). The chat and notification subsystem was implemented using Google Firestore with Firebase-based user authentication.

Decentralized File Sharing System

I implemented a decentralized web platform for secure file sharing between users.

It's based on Ethereum smart contracts and the InterPlanetary File System (IPFS). I built the front end using the JavaScript API for the Ethereum blockchain and IPFS. I executed the back-end code only within the smart contracts implemented using Solidity. A central server doesn't exist in the application at all. That system has a futuristic concept for file sharing without the presence of a third-party server.

I connected with Ethereum network using the Metamask extension for the Google Chrome browser. The main innovation, which the implementation of this system provides, is the protection of file content located on the IPFS network. The files are protected using symmetric-key cryptography, and related keys for protection are encrypted with public/private key pair.

I developed that system as an individual project, meaning I was responsible for the front and back end of this decentralized web application.

Generic CMS for eCommerce Websites

I implemented an admin sales management platform for sophisticated and semi-complex web stores.

It allows the manipulation of products, categories, brands, coupons, vouchers, invoices, suppliers, orders, etc. In addition to selling, there is also an option to add new text articles to the company blog. Various statistical parameters are also available (based on sales trends), stock balances can be tracked, as well as the distribution of products in any single shop can be tracked.

It can be integrated into any client's website because it is entirely independent of the particular sales company. There are also multiple user groups in the system with different degrees of privileges. We built it for the Serbian market, and several online sales companies currently use it. As the platform facilitates a large volume of sales, so much of the paperwork is automated, which saves a significant amount of time for shop administrators.

The platform was implemented using the Laravel framework and MySQL database. The front end was built using the Bootstrap library and standard technologies like HTML, CSS, JavaScript, and jQuery.

Audio Device Store

https://4audio.rs
Above all, the project is intended to be a website and webshop of a company that has been a leading seller, importer, and distributor of audio equipment in Belgrade for 20 years. The company represents only world-renowned audio brands and is the exclusive importer for the Republic of Serbia. It also specializes in all facilities where music is an indispensable element of everyday events.

It is an advanced eCommerce website implemented in the Laravel framework using a MySQL database as data storage. The site has an MVC architecture, and I built the front end using the Bootstrap library and standard technologies like HTML, CSS, JavaScript, and jQuery. The developed website includes several different user groups, as well as an admin platform through which it is possible to manage the web store's content.

I was responsible for the implementation of the entire website.

University Audio Courses

I developed the entire front and back end of a website that hosts recorded classes for many courses at the University of Belgrade, School of Electrical Engineering.

The site is beneficial to students in their exam preparation. The audio recordings are divided by university levels, sections, and exam titles, and they are playable through a website-embedded audio player. All audio files were stored with compression on a central server, and we used a database to index them.

Along with implementing the MVC architecture in the app, I built the back end using the Laravel framework and the front end using JavaScript, jQuery, Ajax, HTML, CSS, and Bootstrap.
2018 - 2019

Master's Degree in Software Engineering

University of Belgrade, School of Electrical Engineering - Belgrade, Serbia

2014 - 2018

Bachelor's Degree (Honors) in Software Engineering

University of Belgrade, School of Electrical Engineering - Belgrade, Serbia

Libraries/APIs

jQuery, JDBC, JMS, PayPal API, Stripe API, Node.js, React

Tools

Git, Xcode, Android Studio, PhpStorm, Visual Studio, IntelliJ IDEA, Trello, Jira, GCC, Apache, Asana, NGINX, GitLab, Adobe Experience Manager (AEM), Adobe Target, Helm, Borland C, ChatGPT

Frameworks

Flutter, Laravel, Bootstrap, Spring Boot, Hibernate, JPA, CodeIgniter, JSF, PHPUnit, FuelPHP, Angular, React Native

Languages

Dart, Java, C, PHP, C++, JavaScript, HTML, CSS, Assembly, Solidity, Python

Paradigms

REST API Architecture, Object-oriented Programming (OOP), Model View Controller (MVC), Concurrent Programming, Socket Programming, Mobile Development, Design Patterns

Storage

MySQL, PostgreSQL, Microsoft SQL Server, SQLite, Cloud Firestore, MongoDB, Amazon S3 (AWS S3), Google Cloud

Platforms

Firebase, Android, iOS, Linux, Windows, Ubuntu, SuiteCRM, Docker, CentOS, Kubernetes, Amazon Web Services (AWS), Amazon EC2, JavaFX, Kernel, WordPress, Azure, Amazon, FlutterFlow

Other

Back-end, Full-stack, Ajax, Web Development, UML Diagrams, Cloud, Front-end, Cross-platform App Development, Public-key Cryptography, Machine Learning, Payment APIs, In-app Purchases, Front-end Development, Data Warehousing, Compilers, Operating Systems, Network Engineering, Neural Networks, Architecture, Artificial Intelligence (AI), Childcare, Education, Marketplaces

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