Dejan Milosevic, Developer in Lisbon, Portugal
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Dejan Milosevic

Verified Expert  in Engineering

Software Developer

Lisbon, Portugal
Toptal Member Since
November 29, 2015

Dejan is an experienced professional with expertise in top Java and JavaScript frameworks, including Spring/JEE. He is skilled in HTML, CSS, and various JavaScript libraries, alongside proficiency in SQL and NoSQL databases. Dejan excels in designing and managing microservice architectures and has extensive hands-on experience. As an experienced engineering manager, he effectively leads teams of engineers.


LineUp Fuerteventura
Python, JavaScript, Airtable, Shopify, Shopify API, SQL, REST APIs...
Online Freelance Agency
Java, Amazon Web Services (AWS), Microservices, API Integration, Python, SQL...
Finanex, Cyprus
Lightstreamer, Apache Wicket, WebSockets, PostgreSQL, JBoss, EclipseLink...




Preferred Environment

Git, IntelliJ IDEA

The most amazing...

...project I've worked on was a new financial instrument, a derivative of binary options, with integrated payment gateways and real-time money payments.

Work Experience

Senior Software Architect

2022 - PRESENT
LineUp Fuerteventura
  • Analyzed and optimized the whole IT system, integrating sales, rentals, and schools in one single back end.
  • Replaced and upgraded integrations between various platforms using automation and API calls.
  • Gathered info about existing business processes and developed new IT solutions to optimize them.
Technologies: Python, JavaScript, Airtable, Shopify, Shopify API, SQL, REST APIs, Data Analysis, Shopify Customizations, Shopify Plus, Custom Shopify Apps, Back-end, Full-stack Development, APIs, CSS, HTML, HTTP REST, eCommerce, Full-stack

Engineering Lead

2016 - 2022
Online Freelance Agency
  • Led a team of eight engineers. Monitored performance and coached team members.
  • Designed the microservices architecture of new projects.
  • Negotiated and evaluated different options for project implementation with various departments, including legal, accounting, marketing, and compliance departments, and coordinated with the project manager to set goals and timelines.
Technologies: Java, Amazon Web Services (AWS), Microservices, API Integration, Python, SQL, Architecture, REST APIs, Back-end, MongoDB, APIs, Data Pipelines, HTML, HTTP REST, Full-stack


2013 - 2015
Finanex, Cyprus
  • Developed a stand-alone Java application that pushed data to different clients (HTML, Flash, iOS, Android).
  • Developed a web application in Wicket and integrated it with a front-end output.
  • Integrated payment gateways and executed real-time money payments.
  • Connected to various 3rd-party APIs, including Mailchimp, GetResponse, Facebook, and Lightstreamer.
  • Connected to market data providers with real-time streaming quotes such as IQFeed and Morningstar.
  • Investigated possible technologies for a project and made a selection based on a cost vs. functionality trade-off criteria.
  • Interviewed new candidates to join the team for Java back-end and HTML and CSS front-end positions.
  • Prioritized and made strategic decisions based on available resources and business requirements.
  • Met with investors and affiliates, presenting technical details of a project.
  • Administered deployments on Amazon AWS (EC2, RDS) from the initial account creation to the working state of the servers.
Technologies: Lightstreamer, Apache Wicket, WebSockets, PostgreSQL, JBoss, EclipseLink, Spring, JAX-RS, Java, API Integration, SQL, REST APIs, Back-end, Full-stack Development, APIs, CSS, HTML, MyBatis, HTTP REST, Full-stack

Java Back-end and Web Developer

2010 - 2013
  • Developed various web applications.
  • Modeled and administered MySQL and PostgreSQL databases.
  • Developed a rich web UI using Sencha Ext JS.
  • Created REST services and clients.
Technologies: PostgreSQL, MySQL, JBoss, Apache Tomcat, Hibernate, EJB3, Spring, Apache Struts, Ext JS, JAX-RS, Java, API Integration, SQL, REST APIs, Back-end, Full-stack Development, APIs, CSS, HTML, MyBatis, HTTP REST, Full-stack

Java Web Developer

2007 - 2010
European Dynamics - Athens
  • Developed business web applications for government e-procurement systems.
  • Worked on database modeling (MySQL).
  • Administered several deployments on client machines (Linux & Windows).
  • Analyzed client requirements.
  • Wrote precise use cases based on client requests.
  • Led a team of developers.
Technologies: Orbeon Forms, EJB 3, MySQL, JBoss, Apache Tomcat, Spring, JavaScript, jQuery, Jakarta Server Pages (JSP), Java, SQL, Back-end, Full-stack Development, APIs, CSS, HTML, MyBatis, Full-stack

Java Web Developer

2006 - 2007
Komercijalna Banka AD, Belgrade
  • Developed enterprise web applications and web services.
  • Administered IBM WebSphere application server through the administrative console and additional scripting.
  • Developed stand-alone Java applications that run on legacy IBM mainframes.
  • Accessed and incorporated legacy CICS transactions from Java.
  • Administered IBM DB2 and Microsoft SQL Server databases.
Technologies: JUnit, WebSphere MQ, ActiveMQ, WebSphere, Hibernate, Spring, Apache Struts, Servlet, Jakarta Server Pages (JSP), Java, API Integration, SQL, Back-end, Full-stack Development, APIs, CSS, HTML

Back- and Front-end Developer

2005 - 2006
BIS Beograd, Belgrade
  • Developed applications for financial bookkeeping and accounting.
  • Worked on database modeling.
  • Administered client installations on Windows and Linux machines.
  • Remotely assisted clients with technical issues.
Technologies: User Interface (UI)

Belgian Public Procurement E-platform

System for electronic public procurement for Belgian public institutions. Contains all steps in a procurement process including listing the projects, searching and narrowing down suppliers, and organizing the reverse e-auctions.

New Trading Platform

A platform that offers a different approach to online trading. Individual traders face each other directly, instead of facing professional counterparts such as dealers and institutional investors whose capital, skills, information, and tools far exceed those of the individual investors.
2000 - 2006

Bachelor of Science Degree in Electrical Engineering

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


MyBatis, jQuery, REST APIs, DBUnit, RESTEasy, JAX-RS, jQuery UI, Shopify API


Servlet, Git, IntelliJ IDEA, Eclipse IDE, Apache Ant, Apache Tomcat, Subversion (SVN), Apache Maven, ActiveMQ, Apache, Shopify Plus


JPA, JUnit, iBATIS, Hibernate, Spring Security, Spring MVC, Spring, Apache Struts, Apache Struts 2, Jakarta Server Pages (JSP), Jersey, Ext JS, Apache Wicket


Java, HTML, SQL, Hibernate Query Language (HQL), JavaScript, HTML5, Python, CSS3, CSS, C++


REST, Microservices


JEE, Amazon Web Services (AWS), Shopify, Eclipse, WebSphere MQ, JBoss, Windows, Linux, WebSphere


MongoDB, JBoss AS, MySQL, PostgreSQL, Data Pipelines, Microsoft SQL Server, IBM Db2, Databases


EclipseLink, EJB 3, API Integration, Architecture, Back-end, Full-stack Development, APIs, HTTP REST, Full-stack, CDI, Data Analysis, Shopify Customizations, eCommerce, EJB3, WebSockets, Lightstreamer, Orbeon Forms, User Interface (UI), Software Development, Software, Airtable, Custom Shopify Apps

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